This study evaluated 27 sunflower inbred lines as maintainers or restorers of fertility for 7 PET-1 and 1 IMS cytoplasmic male sterile (CMS) sunflower lines. Crosses were made between the CMS lines and inbreds and progeny were evaluated for pollen fertility. 22 inbreds maintained sterility of PET-1 CMS lines while 28 restored fertility, indicating different genetic control. All inbreds maintained sterility of the IMS line. Only one inbred partially restored the IMS line. Cytological pollen analysis provided a more accurate assessment of fertility restoration than visual observation alone. The identification of restorers for the diverse CMS sources could enable the development of new hybrids with increased genetic
Haploid induction of allelic diversity populations in maizeNaveen Jakhar
This document summarizes a power point presentation on haploid induction of allelic diversity in maize populations. It discusses two hypotheses for how haploid embryos are formed, outlines the objectives and methods used, and summarizes the results. The methodology involved selecting maize races from different elevations and examining their haploid induction rates when crossed with a maternal haploid inducer. Races from low elevations had significantly higher haploid induction rates than mid or high elevation races. Certain races like TuxpeñoNorteño also had significantly higher rates than others like Conico. The document provides background on haploid induction and doubling techniques in maize breeding.
Utilizing genomic resources for understanding the stay-green QTLs interaction...ICRISAT
Sorghum [Sorghum bicolor (L.) Moench] is a fifth most important cereal crop in the world providing food, fodder/forage and bio-fuel. The postrainy sorghum crop in India is grown on residual moisture and inadvertently faces terminal drought. Stay-green (delayed senescence) is a post-flowering drought tolerance response, which help plants to maintain photosynthetically active leaf area and continue to fill their grains normally under stress. Sorghum crop is referred to express functional type of stay-green and the trait has been mapped to six major QTLs viz., Stg1, Stg2, Stg3A, Stg3B, StgC and Stg4. However, the gap in understanding the key mechanism has not been deciphered clearly. In this scenario to understand the actual mechanism of the stay-green pathway the information from different crops on candidate genes responsible for stay-green phenotype were considered viz., STAY-GREEN (SGR) along with one or two homologous (SGR1or NYE1/SGRL); Pheophytin Pheophorbide Hydrolase (PPH); Pheophorbide a Oxygenase (PA); Red Chlorophyll Catabolite Reductase (RCCR); Non-Yellow Coloring (NYC) and it’s homologous NYC1-Like (NOL); 7-Hydroxymethyl Chlorophyll a Reductase (HCAR) from Zea mays, Arabidopsis thaliana and Orzya sativa. Apart from these, senescence associated genes SAG2, SAG102 and SAG39 were also considered from Arabidopsis thaliana and Orzya sativa respectively. The sequence and functional/annotation information for these genes retrieved for sequence similarity search and it has revealed 45 to 88 % of similarity in sorghum. The mapping of these candidate gene sequences within the defined QTL regions contributing for Stay-green has given an insight to utilize the re-sequencing data for improved drought tolerance in sorghum. Utilizing genomic resources for understanding the stay-green QTLs interactions in Sorghum.
Development of high yielding medium duration groundnut tolerant to early leaf...Tropical Legumes III
Early Leaf Spots (ELS) is one of the major fungal foliar diseases in Mali negatively affecting agronomic performance of groundnut where yield reduction can exceed 30%. It is important to develop new varieties that combine yield potential and tolerance to ELS, scientist under the umbrella of TL III aimed to develop highly yielding medium duration groundnut tolerant to ELS which is discussed in the poster presentation.
Generation Mean Analysis of Some Agronomic Traits in HB42xSabini Barley CrossPremier Publishers
This study investigated gene effects and interactions controlling agronomic traits in a barley cross between HB42 and Sabini cultivars. Six generations (P1, P2, F1, F2, BC1, BC2) were evaluated for days to heading, days to maturity, spike length, number of kernels per spike, thousand kernel weight, and grain yield per plant. Generation mean analysis showed significant differences among generations for all traits except grain yield. Heterosis estimates revealed the F1 had higher spike length and thousand kernel weight than both parents, but lower number of kernels per spike and grain yield, indicating negative heterosis. Scaling tests and genetic variance component analysis suggested non-additive gene effects like ep
Synthetic hexaploid wheat is an artificial hybrid of tetraploid wheat and Aegilops tauschii that contains 42 chromosomes. It was first created in 1946 and numerous synthetic hexaploid wheats have since been produced globally. Compared to natural hexaploid wheat, synthetic hexaploid wheat is estimated to have lost fewer genes following polyploidization and shows subgenome dominance of the D genome over the A and B genomes. Allopolyploidization leads to genomic changes in synthetic hexaploid wheat including DNA elimination, gene silencing, and duplication. Molecular characterization shows that synthetic hexaploid wheat retains parental expression level dominance and has nonadditively activated gene expression contributing to its hybrid vigor.
Genome-wide survey and characterization of AP2/ERF and HSP 90 gene family in ...ICRISAT
APETALA2/Ethylene Response Factor (AP2/ERF) and Heat Shock Protein 90 (HSP90) are important classes of transcription factor and chaperone proteins known to play a significant role under stress. Productivity and yield of legume crops are severely affected by environmental and pathogen stresses.
24 June 2015
Bottlenecks -- some ramblings and a bit of data from maize PAGXXIIjrossibarra
1) The document discusses how population bottlenecks during domestication can reduce genetic diversity and influence patterns of variation across the genome.
2) Bottlenecks are shown to increase the number of rare variants, affect site frequency spectra, and influence the effects of purifying selection. They can also mimic signals of positive selection.
3) Studies of maize domestication estimate a weaker bottleneck than previously thought, with rapid recent population growth increasing diversity from resequencing data. However, selection still reduces diversity more in genic regions relative to intergenic regions.
Reproductive Parameters of Diastocera trifasciata (Fabricius, 1775) (Coleopte...AkesseNarcice
This work is the first which describes the details of the stages of the development, reproductive parameters. It provides the durations of the different stages of development of this species
Diastocera trifasciata, formerly known as Analeptes trifasciata, which causes crop losses in many West African cashew nut producing countries
Haploid induction of allelic diversity populations in maizeNaveen Jakhar
This document summarizes a power point presentation on haploid induction of allelic diversity in maize populations. It discusses two hypotheses for how haploid embryos are formed, outlines the objectives and methods used, and summarizes the results. The methodology involved selecting maize races from different elevations and examining their haploid induction rates when crossed with a maternal haploid inducer. Races from low elevations had significantly higher haploid induction rates than mid or high elevation races. Certain races like TuxpeñoNorteño also had significantly higher rates than others like Conico. The document provides background on haploid induction and doubling techniques in maize breeding.
Utilizing genomic resources for understanding the stay-green QTLs interaction...ICRISAT
Sorghum [Sorghum bicolor (L.) Moench] is a fifth most important cereal crop in the world providing food, fodder/forage and bio-fuel. The postrainy sorghum crop in India is grown on residual moisture and inadvertently faces terminal drought. Stay-green (delayed senescence) is a post-flowering drought tolerance response, which help plants to maintain photosynthetically active leaf area and continue to fill their grains normally under stress. Sorghum crop is referred to express functional type of stay-green and the trait has been mapped to six major QTLs viz., Stg1, Stg2, Stg3A, Stg3B, StgC and Stg4. However, the gap in understanding the key mechanism has not been deciphered clearly. In this scenario to understand the actual mechanism of the stay-green pathway the information from different crops on candidate genes responsible for stay-green phenotype were considered viz., STAY-GREEN (SGR) along with one or two homologous (SGR1or NYE1/SGRL); Pheophytin Pheophorbide Hydrolase (PPH); Pheophorbide a Oxygenase (PA); Red Chlorophyll Catabolite Reductase (RCCR); Non-Yellow Coloring (NYC) and it’s homologous NYC1-Like (NOL); 7-Hydroxymethyl Chlorophyll a Reductase (HCAR) from Zea mays, Arabidopsis thaliana and Orzya sativa. Apart from these, senescence associated genes SAG2, SAG102 and SAG39 were also considered from Arabidopsis thaliana and Orzya sativa respectively. The sequence and functional/annotation information for these genes retrieved for sequence similarity search and it has revealed 45 to 88 % of similarity in sorghum. The mapping of these candidate gene sequences within the defined QTL regions contributing for Stay-green has given an insight to utilize the re-sequencing data for improved drought tolerance in sorghum. Utilizing genomic resources for understanding the stay-green QTLs interactions in Sorghum.
Development of high yielding medium duration groundnut tolerant to early leaf...Tropical Legumes III
Early Leaf Spots (ELS) is one of the major fungal foliar diseases in Mali negatively affecting agronomic performance of groundnut where yield reduction can exceed 30%. It is important to develop new varieties that combine yield potential and tolerance to ELS, scientist under the umbrella of TL III aimed to develop highly yielding medium duration groundnut tolerant to ELS which is discussed in the poster presentation.
Generation Mean Analysis of Some Agronomic Traits in HB42xSabini Barley CrossPremier Publishers
This study investigated gene effects and interactions controlling agronomic traits in a barley cross between HB42 and Sabini cultivars. Six generations (P1, P2, F1, F2, BC1, BC2) were evaluated for days to heading, days to maturity, spike length, number of kernels per spike, thousand kernel weight, and grain yield per plant. Generation mean analysis showed significant differences among generations for all traits except grain yield. Heterosis estimates revealed the F1 had higher spike length and thousand kernel weight than both parents, but lower number of kernels per spike and grain yield, indicating negative heterosis. Scaling tests and genetic variance component analysis suggested non-additive gene effects like ep
Synthetic hexaploid wheat is an artificial hybrid of tetraploid wheat and Aegilops tauschii that contains 42 chromosomes. It was first created in 1946 and numerous synthetic hexaploid wheats have since been produced globally. Compared to natural hexaploid wheat, synthetic hexaploid wheat is estimated to have lost fewer genes following polyploidization and shows subgenome dominance of the D genome over the A and B genomes. Allopolyploidization leads to genomic changes in synthetic hexaploid wheat including DNA elimination, gene silencing, and duplication. Molecular characterization shows that synthetic hexaploid wheat retains parental expression level dominance and has nonadditively activated gene expression contributing to its hybrid vigor.
Genome-wide survey and characterization of AP2/ERF and HSP 90 gene family in ...ICRISAT
APETALA2/Ethylene Response Factor (AP2/ERF) and Heat Shock Protein 90 (HSP90) are important classes of transcription factor and chaperone proteins known to play a significant role under stress. Productivity and yield of legume crops are severely affected by environmental and pathogen stresses.
24 June 2015
Bottlenecks -- some ramblings and a bit of data from maize PAGXXIIjrossibarra
1) The document discusses how population bottlenecks during domestication can reduce genetic diversity and influence patterns of variation across the genome.
2) Bottlenecks are shown to increase the number of rare variants, affect site frequency spectra, and influence the effects of purifying selection. They can also mimic signals of positive selection.
3) Studies of maize domestication estimate a weaker bottleneck than previously thought, with rapid recent population growth increasing diversity from resequencing data. However, selection still reduces diversity more in genic regions relative to intergenic regions.
Reproductive Parameters of Diastocera trifasciata (Fabricius, 1775) (Coleopte...AkesseNarcice
This work is the first which describes the details of the stages of the development, reproductive parameters. It provides the durations of the different stages of development of this species
Diastocera trifasciata, formerly known as Analeptes trifasciata, which causes crop losses in many West African cashew nut producing countries
Genetic variability, heritability, genetic advance, genetic advance as percen...Premier Publishers
This document summarizes a study on the genetic variability, heritability, genetic advance, and character associations of 49 Ethiopian mustard landraces. The study found significant genetic variability among the accessions for all traits measured. Traits like seed yield, oil yield, and plant height showed high genotypic and phenotypic variation, indicating potential for selection. Heritability was highest for thousand seed weight, days to flowering, stand percent, and oil quality traits. Positive correlations were found between seed yield and traits like oil content, oil yield, plant height and seed yield per plant. Primary branches and oil yield showed direct positive effects on seed yield per plot. Seed yield, oil content, oil yield and primary branches were determined to be
When breeding diploid potatoes, tetraploid progeny can result from the union of 2n eggs and 2n pollen in 2x-2x crosses. Thirty-three crosses were made to examine tetraploid progeny frequency in 2x-2x crosses. All crosses were between S. tuberosum dihaploids and diploid self-compatible donors, M6 and DRH S6-10-4P17. Using chloroplast counting for ploidy determination, the frequency of tetraploid progeny was as high as 45% in one of the 33 crosses. Based upon single nucleotide polymorphism (SNP) genotyping, the tetraploid progeny were attributed to bilateral sexual polyploidization (BSP), which is caused by the union of 2n egg and 2n pollen. Dihaploids were identified that produce lower frequencies of 2n eggs. The results of this study suggest that S. tuberosum dihaploids with a high frequency of 2n eggs should be avoided in 2x - 2x crosses for diploid breeding programs.
Chasing a Unicorn for Model Host-Microbiome-Systems Jonathan Eisen
This document summarizes a presentation given by Jonathan Eisen on his research into the rice microbiome. Some key points:
- Eisen studies how the rice plant and its genotype influence the microbial communities that colonize its roots (rhizosphere, rhizoplane, endosphere).
- In greenhouse experiments, rice genotype explained a significant amount of variation in root microbial communities. Certain microbes were enriched or depleted across root compartments.
- Field experiments also found the rice cultivation site and farming practices influenced root microbiome composition.
- Dynamics studies showed microbes rapidly colonize roots within 24 hours of transplantation, with shifts in community composition over time.
- Network analysis revealed microbial modules involved in methane cycling that varied across
Deleterious Alleles in maize, talk from PAGXXIIjrossibarra
This document discusses deleterious alleles in maize and their implications. It finds that:
1) Maize accumulates around 90 new mutations per meiosis, most of which are deleterious. Studies have found many new mutations of large effect in maize.
2) Genes show signatures of purifying selection, with deleterious variants found at lower frequencies compared to non-genic regions. These deleterious variants likely contribute to inbreeding depression.
3) Analysis of a panel of 282 maize inbreds found that genes containing deleterious alleles were enriched in genome-wide association studies hits for traits related to heterosis.
4) The patterns observed are consistent with a model of complementation playing
The document summarizes research on the selection and demography of maize evolution. It discusses how maize was domesticated from its wild ancestor, teosinte, through selection on specific genes like tga1 and tb1 that contributed to changes in plant architecture. It also describes the spread of maize from its center of domestication in Mexico to other regions, noting evidence of selection during this spread. Genomic analyses reveal thousands of genes underwent changes between teosinte and modern maize varieties through both hard sweeps on individual genes and polygenic adaptation.
Evolutionary Genetics of Complex Genomejrossibarra
This document discusses the genetic adaptations that occurred during the domestication of maize from its wild ancestor, teosinte. It provides examples of genes that showed changes in regulatory sequences or expression levels during domestication, allowing traits like ear size and plant architecture to evolve. Genomic studies have found that a large portion of selective sweeps during maize domestication occurred in intergenic regulatory regions, suggesting selection acted upon standing genetic variation to change gene expression. Maize was domesticated independently in Mexico and South America, with genetic differences accumulating between the two gene pools over time.
1) The document describes research on adaptation to high altitudes in maize (Zea mays).
2) It finds evidence of high altitude adaptation in wild teosinte populations in Mexico, as well as parallel adaptation in domesticated highland maize varieties through genetic changes including inversions.
3) The research identifies candidate genes and loci underlying high altitude adaptation through genome-wide association studies and comparisons to teosinte, finding evidence of past adaptive introgression from teosinte into highland maize populations.
The document reports on a study that identified quantitative trait loci (QTLs) associated with stigma exertion rate and spikelet number per panicle in rice. Eight QTLs for single stigma exertion, double stigma exertion, and total stigma exertion were detected on chromosomes 6, 10, 11 and three QTLs for spikelet number per panicle were identified on chromosomes 1 and 3. One QTL for spikelet number was detected in two different environments. The study provides information to aid in fine mapping, gene cloning and marker-assisted selection for improving hybrid rice seed production.
This document discusses the diallel selective mating approach (DSM) for genetic improvement of autogamous crops. DSM involves three steps: 1) a parental diallel series of crosses between multiple parents, 2) F1 diallel series of crosses between F1 plants, and 3) selective mating series where selected F2 plants are intercrossed and selfed in successive generations. The goal is to accumulate desirable genes and increase recombination through restoring heterozygosity via intermating selected plants over multiple cycles. While it broadens the genetic base, DSM is more complex than pedigree methods and success depends on identifying desirable plants in segregating generations.
This document summarizes research on the selection and demography of maize evolution. It discusses how maize was domesticated from its wild ancestor, teosinte, through selection for traits like ear size. The document presents several genetic studies that analyzed differences between maize and teosinte genomes and identified genes underlying key domestication traits. It also describes the spread of maize from its origin center in Mexico to other regions in Mexico and South America and genetic differences between lowland and highland maize varieties.
The document discusses how breeding has impacted genetic diversity in maize genomes over time. It examines changes in ancestry across the maize genome and how the genome has responded to selection for increasing hybrid yield. Specifically, it finds that changing ancestry, not selection sweeps, has driven diversity loss across heterotic groups. The diversity of ancestral lines making up modern inbreds has decreased as germplasm pools have become smaller and more homogeneous. Within a single breeding program, genetic drift in small breeding populations also reduced diversity despite selection for yield.
Genetic Variability, Heritability and Genetic Advance Analysis in Upland Rice...Premier Publishers
The experiment was conducted to assess genetic variability, heritability and genetic advance for yield and yield related traits in some upland rice genotypes. A total of 23 rice genotypes were evaluated in a randomized complete block design with three replications in 2017 at Pawe and Assosa. Analysis of variance revealed significant difference among the genotypes for most of the traits at individual and across locations, and error variances of the two locations were homogenous for most of the traits including grain yield. Moreover, the genotypes showed wider variability for grain yield in the range between 3707-6241kg/ha, 4853-7282kg/ha and 4280-6761kg/ha at Pawe, Assosa and over locations, respectively. A relatively high (>20%) phenotypic and genotypic coefficient of variations were estimated merely for number of unfilled grains per panicle. High heritability estimates (> 60%) were obtained for all of the traits, except plant height and Protein content. A relatively high genetic advance was obtained for traits like unfilled grains per panicle and fertile tiller per plant. Thus, this study revealed that there was higher genetic variability among the tested genotypes, which could be potentially exploited in future breeding programs.
Genetic variability, correlation and path coefficient analysisMoniruzzaman Shohag
This document reports on a study of genetic variability, correlation, and path coefficient analysis of chickpea (Cicer arietinum L.) genotypes. It found significant genetic variability for traits like number of secondary branches, plant height, number of pods per plant, 100 seed weight, and seed yield per plant. Correlation analysis revealed strong positive associations between seed yield and number of pods per plant and 100 seed weight. Path coefficient analysis showed that number of pods per plant and 100 seed weight had high direct effects on seed yield and should be important selection criteria for improving chickpea varieties.
Fast forward genetic mapping provides candidate genes for resistance to fusar...ICRISAT
This document summarizes a study that used a combination of whole genome sequencing and bulk segregant analysis to identify candidate genes for fusarium wilt and sterility mosaic disease resistance in pigeonpea. Researchers developed resistant and susceptible bulks from a mapping population and sequenced these along with a resistant parent. They identified over 35,000 SNPs between the bulks and found four candidate genes on two chromosomes associated with initiating defense mechanisms against fungal and viral diseases. This approach combined fast genetic mapping with genome sequencing to efficiently identify targeted genomic regions controlling important traits.
Heritability and genes governing number of seeds per pod in west african okra...Alexander Decker
1) The study evaluated the genetic inheritance of number of seeds per pod in four crosses of West African okra accessions.
2) Generation mean analysis showed additive genetic effects significantly accounted for variability in number of seeds per pod in all crosses.
3) Narrow sense heritability estimates were moderately high in all crosses, suggesting selection could provide genetic improvement for seed yield.
This document summarizes research on adaptation in maize during and after domestication. It discusses how maize adapted through standing genetic variation, regulatory changes, and polygenic adaptation using multiple mutations and alleles from teosinte. It describes the origins and spread of maize from its ancestor teosinte in Mexico around 9,000 years ago to other regions of Mexico, South America, and beyond. The differences between lowland and highland maize populations are also summarized.
Historical Genomics of US Maize: Domestication and Modern Breedingjrossibarra
This document summarizes research on the historical genomics of maize evolution in North America. The study applied population genetic analysis to genome sequencing data from maize and teosinte lines to analyze patterns of evolution during domestication and modern breeding. They found distinct impacts of selection during these two epochs and identified candidate genes targeted during each. A separate analysis of a panel of 400 North American corn belt lines genotyped over time found decreasing genetic diversity and ancestral contributions, indicating selection shaped the genetic structure of modern maize.
This document discusses recurrent selection, a plant breeding method involving repeated cycles of selection and intermating within a population. It defines recurrent selection and describes its main features and types, including simple recurrent selection, recurrent selection for general combining ability, recurrent selection for specific combining ability, and reciprocal recurrent selection. The document outlines the procedures, merits, and demerits of these recurrent selection methods. In conclusion, it states that recurrent selection is a cyclic selection method used to improve the frequency of desirable alleles in a breeding population.
23. validation of molecular markers linked to sterility and fertility restore...Vishwanath Koti
This document describes a study that validated molecular markers linked to sterility and fertility restorer genes in Brassica juncea. The study used a cytoplasmic male sterile (CMS) B. juncea line carrying altered mitochondrial DNA from Moricandia arvensis, a maintainer line, and a restorer line. PCR with SCAR and orf108 primers found the markers were only present in the fertile restorer line and F1 hybrid, validating their linkage to the fertility restorer gene. This marker can accelerate breeding of restorer lines and assess hybrid seed purity without lengthy grow-out tests.
Tobacco is a plant native to America that is processed and used in various products like cigarettes, cigars, and pipe tobacco. There are over 70 types of tobacco. It is cultivated in many countries around the world. When smoked or chewed, tobacco exposes the user to nicotine, which is highly addictive similarly to heroin or cocaine, making cessation difficult and causing withdrawal symptoms like depression, anxiety, and cravings. Tobacco use also significantly increases the risk of various illnesses and diseases like cancer, heart disease, and respiratory problems.
Genetic variability, heritability, genetic advance, genetic advance as percen...Premier Publishers
This document summarizes a study on the genetic variability, heritability, genetic advance, and character associations of 49 Ethiopian mustard landraces. The study found significant genetic variability among the accessions for all traits measured. Traits like seed yield, oil yield, and plant height showed high genotypic and phenotypic variation, indicating potential for selection. Heritability was highest for thousand seed weight, days to flowering, stand percent, and oil quality traits. Positive correlations were found between seed yield and traits like oil content, oil yield, plant height and seed yield per plant. Primary branches and oil yield showed direct positive effects on seed yield per plot. Seed yield, oil content, oil yield and primary branches were determined to be
When breeding diploid potatoes, tetraploid progeny can result from the union of 2n eggs and 2n pollen in 2x-2x crosses. Thirty-three crosses were made to examine tetraploid progeny frequency in 2x-2x crosses. All crosses were between S. tuberosum dihaploids and diploid self-compatible donors, M6 and DRH S6-10-4P17. Using chloroplast counting for ploidy determination, the frequency of tetraploid progeny was as high as 45% in one of the 33 crosses. Based upon single nucleotide polymorphism (SNP) genotyping, the tetraploid progeny were attributed to bilateral sexual polyploidization (BSP), which is caused by the union of 2n egg and 2n pollen. Dihaploids were identified that produce lower frequencies of 2n eggs. The results of this study suggest that S. tuberosum dihaploids with a high frequency of 2n eggs should be avoided in 2x - 2x crosses for diploid breeding programs.
Chasing a Unicorn for Model Host-Microbiome-Systems Jonathan Eisen
This document summarizes a presentation given by Jonathan Eisen on his research into the rice microbiome. Some key points:
- Eisen studies how the rice plant and its genotype influence the microbial communities that colonize its roots (rhizosphere, rhizoplane, endosphere).
- In greenhouse experiments, rice genotype explained a significant amount of variation in root microbial communities. Certain microbes were enriched or depleted across root compartments.
- Field experiments also found the rice cultivation site and farming practices influenced root microbiome composition.
- Dynamics studies showed microbes rapidly colonize roots within 24 hours of transplantation, with shifts in community composition over time.
- Network analysis revealed microbial modules involved in methane cycling that varied across
Deleterious Alleles in maize, talk from PAGXXIIjrossibarra
This document discusses deleterious alleles in maize and their implications. It finds that:
1) Maize accumulates around 90 new mutations per meiosis, most of which are deleterious. Studies have found many new mutations of large effect in maize.
2) Genes show signatures of purifying selection, with deleterious variants found at lower frequencies compared to non-genic regions. These deleterious variants likely contribute to inbreeding depression.
3) Analysis of a panel of 282 maize inbreds found that genes containing deleterious alleles were enriched in genome-wide association studies hits for traits related to heterosis.
4) The patterns observed are consistent with a model of complementation playing
The document summarizes research on the selection and demography of maize evolution. It discusses how maize was domesticated from its wild ancestor, teosinte, through selection on specific genes like tga1 and tb1 that contributed to changes in plant architecture. It also describes the spread of maize from its center of domestication in Mexico to other regions, noting evidence of selection during this spread. Genomic analyses reveal thousands of genes underwent changes between teosinte and modern maize varieties through both hard sweeps on individual genes and polygenic adaptation.
Evolutionary Genetics of Complex Genomejrossibarra
This document discusses the genetic adaptations that occurred during the domestication of maize from its wild ancestor, teosinte. It provides examples of genes that showed changes in regulatory sequences or expression levels during domestication, allowing traits like ear size and plant architecture to evolve. Genomic studies have found that a large portion of selective sweeps during maize domestication occurred in intergenic regulatory regions, suggesting selection acted upon standing genetic variation to change gene expression. Maize was domesticated independently in Mexico and South America, with genetic differences accumulating between the two gene pools over time.
1) The document describes research on adaptation to high altitudes in maize (Zea mays).
2) It finds evidence of high altitude adaptation in wild teosinte populations in Mexico, as well as parallel adaptation in domesticated highland maize varieties through genetic changes including inversions.
3) The research identifies candidate genes and loci underlying high altitude adaptation through genome-wide association studies and comparisons to teosinte, finding evidence of past adaptive introgression from teosinte into highland maize populations.
The document reports on a study that identified quantitative trait loci (QTLs) associated with stigma exertion rate and spikelet number per panicle in rice. Eight QTLs for single stigma exertion, double stigma exertion, and total stigma exertion were detected on chromosomes 6, 10, 11 and three QTLs for spikelet number per panicle were identified on chromosomes 1 and 3. One QTL for spikelet number was detected in two different environments. The study provides information to aid in fine mapping, gene cloning and marker-assisted selection for improving hybrid rice seed production.
This document discusses the diallel selective mating approach (DSM) for genetic improvement of autogamous crops. DSM involves three steps: 1) a parental diallel series of crosses between multiple parents, 2) F1 diallel series of crosses between F1 plants, and 3) selective mating series where selected F2 plants are intercrossed and selfed in successive generations. The goal is to accumulate desirable genes and increase recombination through restoring heterozygosity via intermating selected plants over multiple cycles. While it broadens the genetic base, DSM is more complex than pedigree methods and success depends on identifying desirable plants in segregating generations.
This document summarizes research on the selection and demography of maize evolution. It discusses how maize was domesticated from its wild ancestor, teosinte, through selection for traits like ear size. The document presents several genetic studies that analyzed differences between maize and teosinte genomes and identified genes underlying key domestication traits. It also describes the spread of maize from its origin center in Mexico to other regions in Mexico and South America and genetic differences between lowland and highland maize varieties.
The document discusses how breeding has impacted genetic diversity in maize genomes over time. It examines changes in ancestry across the maize genome and how the genome has responded to selection for increasing hybrid yield. Specifically, it finds that changing ancestry, not selection sweeps, has driven diversity loss across heterotic groups. The diversity of ancestral lines making up modern inbreds has decreased as germplasm pools have become smaller and more homogeneous. Within a single breeding program, genetic drift in small breeding populations also reduced diversity despite selection for yield.
Genetic Variability, Heritability and Genetic Advance Analysis in Upland Rice...Premier Publishers
The experiment was conducted to assess genetic variability, heritability and genetic advance for yield and yield related traits in some upland rice genotypes. A total of 23 rice genotypes were evaluated in a randomized complete block design with three replications in 2017 at Pawe and Assosa. Analysis of variance revealed significant difference among the genotypes for most of the traits at individual and across locations, and error variances of the two locations were homogenous for most of the traits including grain yield. Moreover, the genotypes showed wider variability for grain yield in the range between 3707-6241kg/ha, 4853-7282kg/ha and 4280-6761kg/ha at Pawe, Assosa and over locations, respectively. A relatively high (>20%) phenotypic and genotypic coefficient of variations were estimated merely for number of unfilled grains per panicle. High heritability estimates (> 60%) were obtained for all of the traits, except plant height and Protein content. A relatively high genetic advance was obtained for traits like unfilled grains per panicle and fertile tiller per plant. Thus, this study revealed that there was higher genetic variability among the tested genotypes, which could be potentially exploited in future breeding programs.
Genetic variability, correlation and path coefficient analysisMoniruzzaman Shohag
This document reports on a study of genetic variability, correlation, and path coefficient analysis of chickpea (Cicer arietinum L.) genotypes. It found significant genetic variability for traits like number of secondary branches, plant height, number of pods per plant, 100 seed weight, and seed yield per plant. Correlation analysis revealed strong positive associations between seed yield and number of pods per plant and 100 seed weight. Path coefficient analysis showed that number of pods per plant and 100 seed weight had high direct effects on seed yield and should be important selection criteria for improving chickpea varieties.
Fast forward genetic mapping provides candidate genes for resistance to fusar...ICRISAT
This document summarizes a study that used a combination of whole genome sequencing and bulk segregant analysis to identify candidate genes for fusarium wilt and sterility mosaic disease resistance in pigeonpea. Researchers developed resistant and susceptible bulks from a mapping population and sequenced these along with a resistant parent. They identified over 35,000 SNPs between the bulks and found four candidate genes on two chromosomes associated with initiating defense mechanisms against fungal and viral diseases. This approach combined fast genetic mapping with genome sequencing to efficiently identify targeted genomic regions controlling important traits.
Heritability and genes governing number of seeds per pod in west african okra...Alexander Decker
1) The study evaluated the genetic inheritance of number of seeds per pod in four crosses of West African okra accessions.
2) Generation mean analysis showed additive genetic effects significantly accounted for variability in number of seeds per pod in all crosses.
3) Narrow sense heritability estimates were moderately high in all crosses, suggesting selection could provide genetic improvement for seed yield.
This document summarizes research on adaptation in maize during and after domestication. It discusses how maize adapted through standing genetic variation, regulatory changes, and polygenic adaptation using multiple mutations and alleles from teosinte. It describes the origins and spread of maize from its ancestor teosinte in Mexico around 9,000 years ago to other regions of Mexico, South America, and beyond. The differences between lowland and highland maize populations are also summarized.
Historical Genomics of US Maize: Domestication and Modern Breedingjrossibarra
This document summarizes research on the historical genomics of maize evolution in North America. The study applied population genetic analysis to genome sequencing data from maize and teosinte lines to analyze patterns of evolution during domestication and modern breeding. They found distinct impacts of selection during these two epochs and identified candidate genes targeted during each. A separate analysis of a panel of 400 North American corn belt lines genotyped over time found decreasing genetic diversity and ancestral contributions, indicating selection shaped the genetic structure of modern maize.
This document discusses recurrent selection, a plant breeding method involving repeated cycles of selection and intermating within a population. It defines recurrent selection and describes its main features and types, including simple recurrent selection, recurrent selection for general combining ability, recurrent selection for specific combining ability, and reciprocal recurrent selection. The document outlines the procedures, merits, and demerits of these recurrent selection methods. In conclusion, it states that recurrent selection is a cyclic selection method used to improve the frequency of desirable alleles in a breeding population.
23. validation of molecular markers linked to sterility and fertility restore...Vishwanath Koti
This document describes a study that validated molecular markers linked to sterility and fertility restorer genes in Brassica juncea. The study used a cytoplasmic male sterile (CMS) B. juncea line carrying altered mitochondrial DNA from Moricandia arvensis, a maintainer line, and a restorer line. PCR with SCAR and orf108 primers found the markers were only present in the fertile restorer line and F1 hybrid, validating their linkage to the fertility restorer gene. This marker can accelerate breeding of restorer lines and assess hybrid seed purity without lengthy grow-out tests.
Tobacco is a plant native to America that is processed and used in various products like cigarettes, cigars, and pipe tobacco. There are over 70 types of tobacco. It is cultivated in many countries around the world. When smoked or chewed, tobacco exposes the user to nicotine, which is highly addictive similarly to heroin or cocaine, making cessation difficult and causing withdrawal symptoms like depression, anxiety, and cravings. Tobacco use also significantly increases the risk of various illnesses and diseases like cancer, heart disease, and respiratory problems.
Gene pyramiding in tomato involves combining desirable genes from multiple parents into a single genotype to improve specific traits. It can enhance disease resistance, drought tolerance, yield, and fruit quality. One study found that pyramiding two virus resistance genes (Ty-2 and Ty-3) in tomato improved resistance to three viruses and had higher yields than lines with single genes. Another study found that pyramiding introgressions from wild tomato species S. pennellii improved drought tolerance, yield, soluble solids content, and the ratio of soluble solids to fruit weight. A third study showed that pyramiding quality trait genes increased antioxidant levels, soluble solids, and yield compared to lines with single introgressions. Gene
This document discusses tobacco (Nicotiana tobaccum). It provides details on the scientific name, family, chromosome number, and origin in America. It notes that tobacco is one of five large genera in the solanaceae family, and that India is the 4th largest producer and 8th largest exporter. It describes the origin and evolution of tobacco from hybridization and chromosome doubling of other Nicotiana species. It outlines the floral biology, selfing and crossing techniques used in tobacco production and breeding. Important tobacco varieties grown in India are also listed.
Rice (Oryza sativa L. 2n = 2x = 24) is a staple food for over half of the world's populationproviding 43% of calorie. Rice yield has experienced many fold jumps since the 1950s. This happened primarily as the result of genetic improvement and increasing harvest index by reducing plant height using the semi-dwarf genes and utilization of heterosis by producing hybrids. Heterosis is the improved or increased function of any biological quality in a hybrid offspring. An offspring exhibits heterosis if its traits are enhanced as a result of mixing the genetic contributions of its parents. Genetic basis of heterosis included overdominance, dominance, and additive effects.
This document discusses a line of male characters that were suppressed and fertile but small and tall. The advantages included yield and resistance while the disadvantages included a reduction of yield during the F2 generation and high cost.
The document provides guidelines for growing hybrid rice, including selecting high-quality seed varieties, soil testing, land preparation, seedbed preparation, transplanting seedlings, fertilizer application, irrigation, weed control, pest management, disease prevention, and harvesting. The presentation aims to help farmers maximize yield through proper cultivation techniques for hybrid rice.
This document provides a history of tobacco use and its health effects. It describes how tobacco was originally used by indigenous peoples in North and South America for thousands of years for medicinal, spiritual, and social purposes. When Europeans discovered tobacco in the 15th century, it was introduced around the world and cultivated as a cash crop. While tobacco had some traditional medical uses, it is now a major public health issue as smoking and smokeless tobacco can cause various cancers, lung and heart diseases, and premature death. The document outlines the spread of tobacco use in India under British colonial rule and the growth of industries like beedi production.
This document discusses advances in crop improvement of root and bulb crops such as carrot, radish, turnip, and onion. For carrot, it describes several new varieties developed in India including Pusa Vristi, Pusa Vasuda, Pusa Asita, and Pusa Meghali. For radish, new varieties discussed include Pusa Jamuni, Pusa Gulabi, and Pusa Mridula. For turnip, varieties mentioned are Pusa Chandrima, Pusa Swarnima, and Purple Top White Globe. Finally, for onion, varieties and hybrids from various public institutions across India are summarized, including Pusa Riddhi, Pusa Soumya, Arka Ujjwal
This document summarizes a seminar on breeding concepts and crop improvement in chickpea. It discusses the floral biology of chickpea, including emasculation and pollination techniques. Breeding objectives for chickpea include increasing yield, biotic and abiotic stress resistance, and quality traits. Key breeding techniques used are mass selection, pure line selection, and hybridization methods like bulk hybridization and pedigree breeding. Varieties developed through these techniques with important traits are mentioned. The document provides information on the present uses of chickpea and production constraints.
Breeding techniques in self pollinated crops presentationDev Hingra
1. Plant breeding techniques for self-pollinated crops include plant introduction, pure line selection, mass selection, pedigree method, bulk method, backcross method, and mutation breeding.
2. Pure line selection involves selecting individual plants, evaluating their progeny, and conducting yield trials to develop uniform varieties. Mass selection composites seed from selected plants for future planting.
3. Plant introduction is an oldest method that can introduce entirely new crop species or superior varieties from other regions. It provides germplasm for breeding programs.
This document summarizes the current status of hybrid rice research and development at IRRI. It discusses trends in hybrid rice adoption globally, with hybrid rice area growing by 2 million hectares from 2007 to 2011 outside of China. It identifies major challenges for hybrid rice in tropical regions like low yield advantages and heterosis. It outlines IRRI's hybrid rice research priorities and efforts to address challenges through developing new parental lines, disease resistance, and seed production technology. The document also summarizes recommendations from a hybrid rice symposium to increase yields, improve seed production, and strengthen public-private partnerships.
This document discusses marker-assisted backcrossing (MAB) for introgressing traits from a donor parent into a recipient line. MAB uses DNA markers linked to target genes/QTLs to aid in selection. Markers can be used for foreground selection of target genes, background selection to recover the recipient genome, and recombinant selection to minimize linkage drag. A case study is described where MAB was used over multiple generations to introgress 5 drought resistance QTLs from a donor rice variety into a recipient variety. Through foreground, background, and recombinant selection using DNA markers, lines were developed with the target QTLs and most of the recipient genetic background.
Plant breeding, its objective and historical development- pre and post mendel...Avinash Kumar
ppt for 1st chapter of plant breeding. it includes defination & objectives of plant breeding, role & challanges of plant breeeders and historical development
Molecular mechanism of male sterility in plant systemShilpa Malaghan
This document summarizes a seminar on molecular approaches for genetic engineering of male sterility. It begins by defining male sterility as the inability of flowering plants to produce functional pollen. It then describes different types of male sterility including genic, cytoplasmic, and chemically-induced sterility. The document discusses the molecular basis of male sterility and anther development, using the T cytoplasm in maize as a model system. It also outlines several genetic engineering approaches that have been used to induce male sterility in crops like tobacco, including the use of ribonuclease genes, a deacetylase system, a two-component barnase system, and engineering chloroplast-induced sterility.
Grain Quality of Doubled Haploid Lines in Rice (Oryza sativa L.) Produced by ...Galal Anis, PhD
Genetic devlopment to imrove genotypes with high quality is the most important approach of rice. Thus, anther culture technique is one of straight forward approaches for improvement of rice cultivars with good grain quality. Therefore, this investigation aimed to develop some doubled haploid lines (DH) through anther culture technique and evaluate them along with their five parents including two check varieties for some nutritional characteristics. The results indicated that the three mineral element contents (Zn, Mn and Fe) of rice grain were clearly different among genotypes (DH), which implied that genotypic variations might provide opportunities to select for higher mineral element content. Analysis of variance revealed that the differences among genotypes were significant for all studied traits. Highly significant positive correlations were recognized among the studied characteristics. Accordingly, Rice lines with the high nutritional values will use as donors for this trait in rice breeding programs for exploitation and in hybridization.
18. identification of ssr markers for hybridity and seed genetic purityVishwanath Koti
This document summarizes a study that identified SSR markers for distinguishing sunflower hybrids from their parental lines. Researchers screened 58 SSR primer pairs on 5 hybrids and their parental lines. They identified two SSR markers, ORS 309 and ORS 170, that can distinguish hybrid KBSH-44 based on complementary banding patterns between the hybrid and its parents. Another marker, ORS 811, was found to specifically identify hybrid KBSH-53. The identified SSR markers provide a tool for assessing genetic purity of these hybrids by detecting the presence of both parental alleles.
The document summarizes a study on the incidence and population build-up of the bean bug Chauliops fallax on different legume crops in Himachal Pradesh, India. The key points are:
1) Surveys found C. fallax infesting soybean, cowpea, black gram and green gram crops across 5 locations, with incidence ranging from 0.2 to 28.8 bugs per 10 plants.
2) Population monitoring on soybean, cowpea and black gram at Palampur showed C. fallax present from crop germination through maturity. Peak populations occurred in early August, with up to 188 bugs on soybean per 10 plants.
3) Rainfall
The development of more efficient and sustainable technologies in the production of materials in ‘in vitro’ cassava (Manihot esculenta Crantz), favor the improvement of seed quality and sanitation of the plant material. The purpose of the research is to evaluate the effectiveness of Pectimorf® (mixed oligo-galacturonide), it’s safe and natural availability in Cuba. It is used as a possible complement or substitute for growth regulators traditionally used in the culture medium for the propagation of this crop in vitro. In this study, the results obtained indicate that, at least, under the experimental conditions, the Pectimorf®, altered patterns of development and distribution of stomata in the leaves of cassava plants, where the effect was most evident when the product is added to the culture medium. The new results contribute to the elucidation of the mechanisms of action of this substance.
This document discusses seed production techniques in cole crops like cauliflower and cabbage. It provides context on India and Himachal Pradesh's production of these crops. It then summarizes the floral biology and self-incompatibility system in cole crops, which is important for hybrid seed production. Techniques for developing hybrids like hybridization and male sterility are also covered. The document emphasizes how hybrids provide benefits like higher yields, adaptability, and market acceptability.
Heterosis, Combining ability and Phenotypic Correlation for Some Economic Tra...Galal Anis, PhD
This investigation was carried out to study heterosis , combining ability and phenotypic correlation in a diallel mating design among 6 Egyptian rice genotypes (excluding reciprocals),including 3 varieties ( Sakha 101, Sakha 104 and Sakha 105),and 3 promising lines (Gz6903, Gz7576 and Gz8479). An experiment was conducted at the research Farm of Rice Research and Training Center (RRTC), Sakha, Kafr EL-sheikh, Egypt during 2013 growing season and designed in a randomize complete block with three replications. Data were recorded on nine traits; days to maturity, chlorophyll content, flag leaf area, plant height, number of panicles / plant, panicle fertility (%), Panicle weight ,1000-grain weight and grain. The results revealed that, the genotypes were highly significant different in all studied characters. The cross (Sakha 101 × GZ6903) showed positive and significant heterosis for mid and better parents for most studied traits. The parent (Sakha 101) was good general combiner for most studied traits. The cross (Sakha 101 × GZ6903) showed positive and highly significant for specific combining ability effects for grain yield and its components.Grain yield was significantly and positively correlated with days to maturity, chlorophyll content, plant height, number of panicles/plant and panicle weight .On the contrary, plant height had significant negative association with days to maturity.
The document discusses a study on the efficacy of aqueous plant extracts in maintaining seed quality of pea (Pisum sativum L.) during storage. The study evaluated the effect of treating pea seeds with aqueous extracts of various plants (Artemisia roxburghii, A. annua, Melia azedarach, Mentha longifolia, M. spicata, Tagetes erecta) at different concentrations (1%, 2%, 4%, 6%) on germination, vigor, and bruchid infestation over a six month storage period. The results showed that seed treatment with aqueous extracts of M. spicata and M. longifolia maintained significantly higher ger
Male sterility systems allow for the efficient production of F1 hybrid seeds in crops. In pigeonpea, three main systems have been developed: genetic male sterility (GMS), cytoplasmic genetic male sterility (CGMS), and temperature sensitive male sterility (TGMS). The first commercial pigeonpea hybrid ICPH-8 was developed using a GMS system, but CGMS is now more widely used due to advantages for large-scale seed production. The first stable CGMS system in pigeonpea utilized cytoplasm from the wild species Cajanus scarabaeoides. Numerous hybrids with significant yield advantages over varieties have been released using CGMS systems. TGMS also shows
Thermo-sensitive Wild aborted Cytoplasmic Genic Male Sterility in Rice (Oryza...Premier Publishers
This paper reported a new male sterility system in rice, thermo-sensitive wild aborted cytoplasmic genic male sterility (TCMS-WA) having majority panicles completely exserted. True breeding TCMS-WA lines were developed from the self-progeny of three heterozygous CMS-WA lines (IR 58025A, IR 62829A, and PMS 3A). The plausible explanation for conserving heterozygosity within the genome of CMS-WA parents and its release was put forward. Presence of two different thermo-sensitive nuclear genes, one for inducing TCMS and the other for reverse TCMS character in CMS-WA parents appeared non-allelic and epistatic to the nuclear recessive ‘fr’ gene. Thermo-sensitive genes were found operative in two mutually exclusive environment-influenced genetic thresholds. TCMS-WA lines were superior to CMS-WA parents for homozygosity, panicle exsertion, and fertility-sterility alteration behavior. Genes controlling panicle exsertion were nuclear genes and independent of the cytoplasmic factor. Presence of three different alleles conferring panicle exsertion was postulated and their allelic relationship might be explained as the allele present in R-line was dominant to that in A-line and the allele present in A-line was dominant to that in B-line. Penetrance and expressivity of genes conferring panicle exsertion were elucidated. The major advantages of using TCMS-WA over TGMS for two-line hybrid development was discussed.
Validation of reference genes in leaf-cutting ant Atta sexdens rubropilosa in...IJEAB
Atta sexdens rubropilosa is an important leaf-cutting ant species considered as a pest in agricultural crop or reforestation areas. Quantitative real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) is a technique that can help us to understand the regulation and the function of a gene. However, its reliability depend on the data normalization. Different normalization strategies can be adopted for qPCR, reference genes has been cited as one of the most effective methods. It has not been identified a universal reference for all organism and experiment. In this way, the validation of reference gene is crucial step. This is the first study to evaluate reference genes for leaf-cutting ants. To this, we analyzed the expression levels of candidate reference genes (act, ef1-alpha, ef1-beta, GAPDH and rpl18) in different developmental stages (larva, pupa and worker) and tissues (head, mesosoma and worker without gaster) of A. sexdens rubropilosa. Four different algorithms (BestKeeper, geNorm, NormFinder and comparative ΔCt method) were used in statistical analysis of the stability of the genes and RefFinder was used to propose a consensus list for ranking the reference genes. Our results showed that the most suitable combinations of reference gene candidates were rpl18 and ef1-alpha for the different developmental stages and rpl18 and ef1-beta for the different tissues. In this work, we also report the obtaining from a putative acetylcholinesterase from A.sexdens rubropilosa (GenBank KY464935), which was used as a target gene to confirm the reliability of reference genes suggested.
Wheat-pea intercropping for aphid control: from laboratory tritrophic approac...InternationalNetwork
Intercropping is an interesting practice to promote the sustainable control of insect pests such as aphids. In particular, volatile organic compounds emitted by aphid-infested intercropped plants may deter other aphid species from their host plants, while attracting natural enemies. In this study, olfactometer and net-cage behavioural assays were first conducted to determine the effect of wheat-pea mixtures combined with aphid infestations on odour preferences of the wheat aphid Sitobion avenae and two associated predator species, the ladybird Harmonia axyridis and the hoverfly Episyrphus balteatus. Healthy wheat plants were preferred by S. avenae, while wheat-pea mixtures combined with aphid infestations were significantly less attractive. H. axyridis preferred odours from healthy wheat plants mixed with aphid-infested pea plants. As for E. balteatus, their searching and oviposition behaviours were stimulated by the different wheat/pea combinations associated with aphid infestations. A field trial was also carried to compare the effect of mix and strip cropping wheat with pea on aphids and their natural enemies with both monocultures. Wheat and pea aphid populations were significantly reduced by both types of intercropping when compared to monocultures. Moreover, higher abundances of hoverflies, lacewings and ladybirds were found in wheat mixed with pea field, followed by strip cropping and monocultures. These findings show that wheat-pea intercropping can be efficient to reduce aphid populations, namely by promoting their biological control.
1) Turnera subulata is a subshrub with distylic flowers common in northeast Brazil. The study examined the pollination biology of a population, focusing on effective pollinators and differences between short- and long-styled flower morphs.
2) Twenty-eight insect species visited the flowers, predominantly bees. Several bee species were effective pollinators, including highly social, polylectic, and one oligolectic species - Protomeliturga turnerae.
3) While P. turnerae shows reproductive dependence on T. subulata, the plant does not depend on this specialized bee as other polylectic visitors also ensure reproductive success.
This document discusses a study on the biological attributes and feeding efficiency of the green lacewing (Chrysoperla carnea) against the sugarcane mealybug (Saccharicoccus sacchari). The objectives were to identify the biological attributes of C. carnea reared on S. sacchari, evaluate population density of S. sacchari on sugarcane varieties, and evaluate the feeding efficacy of C. carnea against S. sacchari. The methodology involved rearing C. carnea and S. sacchari under laboratory conditions and evaluating various biological parameters. Results showed developmental periods for different life stages of C. carnea and number of S. sacchari consumed at each lar
This document provides information about a study investigating heterosis and combining ability in castor (Ricinus communis L.). The study uses a line x tester mating design involving 4 female lines and 20 male testers. The objectives are to estimate heterosis, general and specific combining ability effects, and the nature of gene action for seed yield and its components. Materials and methods describe the experimental design, locations, traits to be measured, and statistical analyses to be conducted, including analysis of variance, estimation of heterosis over better parent and standard check, and combining ability analysis.
Reported some species of plant parasitic nematodes from rhizosphere of peanut...Open Access Research Paper
In order to identify of peanut fields plants parasitic nematodes, 130 samples of soil around the roots of peanut plants were collected in province of Guilan, during the summer and fall of 2011. After extraction, killing, fixation and transferring to anhydrous glycerol, the nematodes were mounted on permanent microscopic slides and nematodes species identified by using light microscope, equipped with digital camera, based on morphological and morphometric characters using valid keys. In this study 20 species belonging 17 genera were identified, that are as followes: 1- Aphelenchoides sacchari 2-Aphelenchus avenae 3- Basiria graminophila 4-Coslenchus costatus 5-Ditylenchus myceliophagus 6-Filenchus vulgaris 7-Helicotylenchus digonichus 8-Heterodera cruciferae 9-Meloidogyne incognita 10-Meloidogyne hapla 11-Merlinius bavaricus 12- Mesocriconemarusticum13- Mesocriconema curvatum 14-Paratylenchus nanus 15-Pratylenchus neglectus 16- Psilenchus hilarulus 17-Quinsulcius capitatus 18-Tylenchorhynchus annulatus 19- Tylenchorhynchus mashhoodi 20- Tylenchus davainei. In thisstudy, 20 species belonging 17 genera were identified that before just 6 Species2-5-7-11-15-16were reported from rhizosphere of Peanut in Iran. Other species (14 Species) are going to report from rhizosphere of Peanut in Iran as a first.
Natural pesticides derived from plants are one of the best alternative approaches for the management of nematodes, as excessive use of chemicals eradicate beneficial organisms in the soil and disturb ecological equilibrium and ultimately cause environmental degradation. Six different weed plants viz., Achyranthes aspera L., Solanum xanthocarpum Schard. & JC wendl. Amaranthus spinosus L., Ranunculus pensylvanicus L.f., Cassia tora L., Oxalis stricta L. were collected from in and around the campus of the Aligarh Muslim University, Aligarh. The nematode eggs and juveniles were exposed at 24, 48 and 72 h in different concentrations (S, S /2, S /10, S /100, S is the standard concentration and S/2, S/10, S/100 is the dilution of Standard solution) of weeds extracts. The plant extract of weeds S. xanthocarpum and A. aspera exhibited highly promising mortality (86-100%) after 72 h exposure period respectively, while the plant extract of O. stricta and C. tora exhibited minimum promising mortality (48-52%) after 24 h of exposure period respectively. There was a gradual decrease in egg hatching with an increase in the concentration of aqueous extracts of weeds. A. aspera, S. xanthocarpum and A. spinosus were found to be most effective in reducing egghatching and increase in mortality of second stage juveniles of M. incognita. Efficacy of treatments improved with increase in their concentration and exposure period. Hatching of larvae and juvenile mortality were strongly influenced by concentration of plants extract.
Population density and spatial distribution of bean bug chauliops fallax swee...kiran Bala
The bean bug Chauliops fallax feeds exclusively on all leguminous crops in most regions of the world. The population density and spatial distribution of bean bug has been investigated on three different host plant i.e. soybean, cowpea and black gram (mash) under mid hill conditions of Himachal Pradesh during 2016. The fields of 600m2 and 300m2 area were selected as a sampling unit for sampling in soybean, cowpea and black gram. Him Palam Hara Soya -1, C-475 and Pant U19 genotypes of soybean, cowpea and mash were selected for the estimation of density and distribution of the bean bug. Different methods viz., Morisita’s index, Index of dispersion and Lewis index were used to calculate the density and distribution of the population of the pest. The mean population of bugs per plant was recorded on soybean (7.25) followed by cowpea (3.01) and black gram (1.21). Studies on knowing the distribution pattern of bean bug population under field conditions revealed that in soybean the distribution of bug was contagious (2.99) while in cowpea (2.44) and black gram (1.87) regular and contagious distribution pattern was found. The Z value of Morisita’s index in case of soybean was 9.98 followed by 5.87 and 3.50 in case of cowpea and black gram. Similar trend was found in case of Index of dispersion and Lewis index. Optimum sample sizes for estimates of the pest density in all the three host plants are presented.
This document summarizes a study that evaluated the relative resistance of 10 soybean cultivars against sucking insect pests in Pakistan. Researchers recorded populations of whiteflies, jassids, and thrips on the cultivars over the growing season. They found that thrips populations were highest overall, followed by jassids then whiteflies. The cultivars E-91-270 and AGS-109 were most susceptible, with the highest recorded populations of thrips and jassids, respectively. PR-142 and AGS-9 were most resistant. Climate factors like temperature and humidity correlated with whitefly and thrips populations but not jassids.
Heterosis in bottle gourd [lagenaria siceraria (mol.) standl.]Dr. Mahesh Ghuge
This study evaluated heterosis for yield and yield traits in bottle gourd hybrids. Twenty-eight F1 hybrids were evaluated along with eight parental lines. Heterosis over the mid-parent and standard check was estimated for 16 quantitative traits. Several hybrids showed significant positive heterosis for traits like fruit yield per vine, average fruit weight, and number of fruits per plant. The highest heterosis for fruit yield per vine was observed in the hybrid Aditi X PSPL, with 68.5% heterosis over the standard check. Positive heterosis was also observed for traits related to fruit quality and plant growth. The results identified hybrids with improved yield and suggest that heterosis breeding can help increase bottle g
Heterosis in bottle gourd [lagenaria siceraria (mol.) standl.]
1
1. Fertility restoration and maintenance of male sterility in different CMS sources of
sunflower (Helianthus annuus L.)
OR
Confirmation of fertility restoration through cytological (pollen) study in different CMS
sources of sunflower (Helianthus annuus L.)
H.P. Meena*and A. J. Prabakaran1
*Corresponding author: Scientist (Plant Breeding), Directorate of Oilseeds Research,
Rajendranagar, Hyderabad, India-30 (Email ID: hari9323@gmail.com)
1
Principal Scientist, Directorate of Oilseeds Research, Rajendranagar, Hyderabad, India-30
ABSTRACT
Seven cytoplasmic male sterile (CMS) lines of sunflower (Helianthus annuus L.) with
PET-1 (H. petiolaris) cytoplasm and one with IMS (H. lenticularis) cytoplasm sources were
crossed with twenty seven testers to assess their maintainer/restorer behavior. In this study we
compared two methods (visual observation vs pollen study) for classifying the
maintainer/restorer into different category. All the inbreds were categorized into maintainer and
restorer based on visual observation (pollen presence or absence) as well as through cytological
observation (pollen study). We observed that cytological study is better for testing fertility
restoration compare to visual observation. While 22 inbreds maintained sterility of CMS PET 1,
28 inbreds restored their fertility. The second CMS line and IMS 852A, was maintained by all
the inbreds indicating involvement of different gene(s). Only one inbred restored their fertility.
Most of the commercial sunflower hybrids are been produced using CMS PET 1. Now with the
identification of restorers for CMS IMS 852A, new more productive commercial hybrids can be
produced. Efforts should be made to locate restorers for CMS GIG 1 for its utilization in
production of sunflower hybrids.
INTRODUCTION
Hybrid breeding has developed successfully in sunflower over the last 40 years since the
identification of cytoplasmic male sterility among progenies of the interspecific cross Helianthus
2. petiolaris x Helianthus annuus by Leclercq (1969) and the subsequent discovery of pollen
fertility restoration genes (Kinman, 1970; Leclercq, 1971; Vranceanu and Stoenescu, 1971). This
source (PET-1 cytoplasm), of cytoplasmic male sterility has proved to be very stable and is used
almost exclusively in breeding programmes throughout the world since late 1970s, when it
replaced the NMS system for producing hybrid seeds that was being used in several European
countries till the early 1970s.
Nevertheless, frequent use of the same sterile cytoplasm increases the genetic
vulnerability of the present sunflower hybrids to diseases and pests. In order to minimize such a
risk, new sources of cytoplasmic male sterility and corresponding fertility restorers are essential
to increase the genetic diversity of the commercial hybrids. Inspite of the fact that new CMS
sources continue to be discovered (Serieys, 2002), there are hardly any reports of their utilization
for commercial hybrid production. The reluctance is presumably due to a lack of superior CMS-
restorer combinations, as well as the time consuming conversion programs of CMS and
restoration genes into inbred lines (Jan et al., 2006).
Success in heterosis breeding is largely dependent on the development of inbreds having
broader genetic base. In general, inbreds with high combining ability and per se performance are
either converted into CMS lines or fertility restorer lines for their future use in hybrid breeding
programmes. Keeping this in view superior inbreds were evaluated for their maintainer and
restorer behaviour, with the objective of identifying diverse sources of CMS maintainers and
restorers. We herein make use of the easy method proposed by Chaudhary et al. (1981), for
ascertaining the pollen fertility of crosses; leading to the identification of selected superior
inbreds as maintainers and restorers of two diverse CMS sources, for the practical use of these
inbreds in future sunflower breeding programme to augment the genetic diversity of sunflower
hybrids. The present study was under taken to find out the fertility restoration ability and
maintainer reaction of the twenty seven testers on the eight CMS lines.
3. MATERIALS AND METHODS
Plant material
The breeding material comprised of two diverse cytoplasmic male sterile sources of
sunflower viz., H. petiolaris and H. lenticularis. In this study we used seven CMS lines from
PET-1 background viz., CMS-852A, CMS-7-1A, CMS-234A, CMS-2A, COSF-1A, COSF-7A,
CMS-10A and one CMS from IMS background viz., IMS-852A maintained by DOR, Hyderabad,
and twenty seven advanced inbred lines (testers) i.e., seven inbreds viz., AKSF-51-6-21, AKSFI-
49-3, AKSFI-49-4, AKSFI-46-2, AKSFI-78, AKSFI-42-1 and AKSFI-52-2 from Akola,
(Maharashtra) center, other three advanced breeding lines i.e., HOHAL-17, HOHAL-25 and
HOHAL-37 from Ludhiana, (Punjab) centre; eight inbred lines i.e., CSFI-5134, CSFI-5055,
CSFI-5261, CSFI-5133, CSFI-5185, CSFI-5033 and CSFI-5075 from Coimbatore, (Tamil Nadu)
centre; other two inbreds i.e., RHAGKVK-1 and RHAGKVK-2 from Bangalore, (Karnataka)
center and five other advanced lines i.e., IB-50, IB-60, IB-61, IB-67 and IB-101 from DOR,
Hyderabad and Selection-I and NDLR-06 from Latur, (Maharashtra) and Nandyal,(Andhra
Pradesh) centres respectively.
Field experiment
Three rows each of the eight cytoplasmic male sterile lines from PET-1 and lenticularis
cytoplasmic backgrounds, and two rows each of the twenty seven testers (inbreds) were planted
during the rabi season of the year 2012-13, with a row to row and plant to plant spacing of 60 cm
x 30 cm. A row length of 4.5 m was maintained. Staggered sowings of male parents, twice at
weekly interval, was done to synchronize the flowering. Recommended agronomic practices
were followed. The heads of male sterile lines and the inbreds were covered with cloth bags at
the ray floret stage i.e., just before the commencement of flower opening. The eight CMS lines
from two different CMS sources were crossed to all the twenty seven inbreds in a line x tester
fashion. Crossing was done by collecting pollen from the inbreds in a petridish with the aid of a
small brush which was applied on five florets each of the corresponding CMS lines between 8 to
11 am and the procedure repeated till the opening of all disc florets. Precautions were taken to
avoid possible contamination. F1 seeds from each of the 216 crosses were collected separately at
4. maturity for assessing the fertility restoration of the 27 inbreds on the 8 CMS lines. The
identification of inbred behaviour, with respect to maintenance and restoration of the
cytoplasmic male sterile sources of sunflower involved in the present study, was conducted
during the kharif season of the year 2013-14 in the Narkhoda Research Farm, DOR, Hyderabad.
F1 seeds from the 216 crosses were planted in a randomized block design (RBD) in replicated
experiment with 2 replications. Two rows of 3 m for each F1 entry were planted maintaining a
row to row distance of 60 cm and a plant to plant distance of 30 cm.
Observation for pollen fertility and sterility
We classified hybrids as maintainer/restorer based on visual observation (pollen present
or absent) as well as through cytological study (pollen study). Based on visual observation, the
pollen parents leading to sterile crosses were classified as maintainers, while those that gave
fertile crosses were classified as restorers of the corresponding CMS lines. Pollen fertility
percentage was calculated by classifying pollen grains as sterile or fertile following
(Chaudharyet al., 1981). For pollen study anthers were collected from all the fertile F1 hybrids.
Pollen grains were treezed out of the anther on glass slide. The fertile and sterile pollen grains
were counted under a light microscope. The pollen fertility was calculated as the ratio between
the number of fertile (round and darkly stained) and sterile (yellow, sheveal, partial stained or
unstained) pollen grain in the microscopic field (Figure 1). Based on fertility, plants were
classified effective as restorers (> 90% pollen fertility), Partial restorers (20-80% pollen fertility),
partial maintainer (1-20% pollen fertility) and effective maintainers (< 1% pollen fertility or no
pollen).
RESULTS AND DISCUSSION
It can be shown from Table 1 that twenty two inbreds namely; RHA 348, 7-1 B, 234 B,
302 B, 378 B, 851 B, 852 B, HA 341, HA 380, GP 290, GP 2008, GP 2111, GP 761, GP 898, M
307-2, M 1008, M 1015, M 1026, DRM 34-2, DRM 70-1, NDOL 87 and LTRR 1 produced
sterile F1s on the CMS PET 1 and CMS ARG 1 sources. Further, all fifty inbreds produced
sterile F1s on CMS GIG 1 as well. Though a minute fraction of aborted pollens (sterile pollens)
was also observed, it can be seen from the Table 1 that twenty eight (RHA 271, RHA 273, RHA
5. 274, RHA 297, RHA 298, RHA 341, RHA 344, RHA 345, RHA 346, RHA 356R, RHA 587,
RHA 859, RHA 6D-1, HAM 161, HAM 174, HAM 175, HAM 180, SF 206, SF 207, SF 208, SF
211, SF 216, BLC P6, PARRUN 1329, RES 834-1, RCR 8297, R 83 R6 and NDLR-1) out of
fifty inbreds produced sufficient fertile F1s with CMS PET 1 and CMS ARG 1. The inbreds
which produced sterile F1s were classified as maintainers, while the ones that produced fertile
F1s were classed as restorers of the respective CMS sources (Table 2).
The present findings agree with the conclusion of Spirova (1990), regarding the
infrequency observed for fertility restoration. This is more obvious in case of CMS GIG 1;
whose fertility was not at all restored by any of the 50 inbreds evaluated in the present study.
Moreover it is known that the restorer of one CMS source may act as a maintainer of other CMS
types. Furthermore, the observation that while all 50 inbreds acted as maintainers of the
cytoplasmic male sterility of GIG 1, 28 common inbreds acted as restorers of both CMS lines
(PET 1 and ARG 1), suggests that while ARG 1 is similar to the French CMS source; PET 1, the
cytoplasm of GIG 1 is different. Petrov and Nenov (1992), drew similar conclusions regarding
the differences of three new CMS sources with the French CMS source PET 1. That the two
CMS sources PET 1 and ARG 1 had different reactions than that of GIG 1; the third CMS source
in the present study, to the inbreds, further indicates a distinct mechanism of cytoplasmic male
sterility operating in CMS GIG 1 (Jan, 2000).
The same pollen parent exhibited different type of fertility restoration behavior in
different CMS line combinations have been found in the material under study. Such type of
results obtained may be due to the minor gene(s) with additive gene action with the cytoplasmic
gene of different CMS line.
The results also revealed that RHA 274 is able to fully restore the fertility of CMS PET 1
and CMS ARG 1, whereas it failed to restore the fertility of CMS GIG 1. These results are in
agreement with those of Havekes et al. (1991). RHA 274, (H. petiolaris restorer line) restorer
with higher oil percentage, has also been found to completely restore the fertility of mutant CMS
HA 89 lines produced by treating maintainer line HA 89 with mitomycin C and streptomycin
(Jan and Rutger, 1988). Likewise RHA 274 has also been observed to restore the fertility of
CMS PI 432513 (Jan and Vick, 1997, 1998, 2007). The restoration of CMS PET 1 and ARG 1 by
6. RHA 274 observed in the present investigations, along with the above reports by various
workers, suggests that RHA 274 is a useful restorer and, this inbred which likely carries Rf1; the
dominant H. petiolaris restorer gene (Jan and Vick, 2007), should be used in hybrid sunflower
breeding programme, especially for higher oil content.
In the present investigations, sufficient restorers were observed for PET 1 and ARG 1.
Since no restorers for CMS GIG 1 could be identified, the cytoplasm of CMS GIG 1 is indicated
to be distinct from those of commercially used PET 1 cytoplasm as well as that of ARG 1. Hence
it is safe to conclude that, while PET 1 can continue to be utilized for the production of
commercial sunflower hybrids, promising hybrids with a different cytoplasm of ARG 1 can also
be obtained. Similarly chances do exist for the development of hybrids with CMS GIG 1
cytoplasmic background. This surmise is based on the fact that Havekes et al. (1991) have
already recovered 50, 81 and 100% male fertile F1 plants derived out of crosses between CMS
GIG 1 and the male fertility restorer lines namely; RGIG 1, RPET 2 and RHA 294, respectively.
7. Table 1: Frequency of F1 sterile pollens (SP) and fertile pollens (FP) from anthers of H. annuus
plants after crossing CMS PET 1 and IMS with 30 inbred testers
8. To be useful for hybrid seed production, a CMS line needs complete male sterility and
female fertility. That male sterility of CMS GIG 1 is stable and completely maintained by 50
different inbred testers, is confirmed in the present experiment. Thus further selection; at least for
fertility restoration of the CMS source GIG 1 is necessary before it can be used for commercial
hybrid production. However since this CMS source (GIG 1), is from H. giganteus, a species
different from the cultivated sunflower (H. annuus), it remains to be seen whether, it will
contribute towards reduction of the genetic vulnerability of worldwide sunflower hybrids, by
providing an alternative to the CMS PET 1 cytoplasm.
Nevertheless, efforts toward identification of different restorers for CMS GIG-1 are
desirable for greater genetic diversity to be used in the development of new restorer inbred lines
(Gimenez and Fick, 1975) and the hybrids. The different CMS lines and their concerned
maintainer and restorer inbreds of sunflower can be utilized directly in maintenance breeding and
hybrid development programme.
ACKNOWLEDGMENT
The authors are thankful to the All India Coordinated Research Project (Sunflower)
centres Bangalore, Akola and Coimbatore for providing the valuable inbred lines. I am extremely
thankful to Dr. A. J. Prabakaran for guiding me and providing cytological facility for pollen
study.
REFERENCES
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cytoplasmic genetic male sterile lines of rice. Oryza, 18: 140-142.
Christov, M., (1992). New sources of male sterility and opportunities for their utilization in
sunflower hybrid breeding. Helia, 15: 41-48.
Gimenez, D.J. and Fick, G. (1975). Fertility restoration of male sterile cytoplasm in wild
sunflower. Crop Sci., 15: 724-726.
9. Havekes, F.W., J.F. Miller and C.C. Jan, (1991). Diversity among sources of cytoplasmic male
sterility in sunflower. Euphytica, 55: 125-129.
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a Helianthus annuus landrace PI-432513. Proceedings of the Sunflower Research
Workshop, January 9-10, 1997, Fargo ND, USA, pp: 1-2.
Jan, C.C. and B.A. Vick, (1998). Cytoplasmic male sterility in sunflower landrace PI 432513 and
the inheritance of fertility restoration. Proceedings of the Sunflower Research Workshop,
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Jan, C.C. and Vick, B.A. (2007). Inheritance and allelic relationships of fertility restoration genes
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Jan, C.C. and Rutger, J.N. (1988). Mitomycin C- and streptomycin-induced male sterility in
cultivated sunflower. Crop Sci., 28: 792-795.
Jan, C.C., (2000). Cytoplasmic male sterility in two wild Helianthus annuus L. accessions and
their fertility restoration. Crop Sci., 40: 1535-1538.
Jan, C.C., J.F. Miller, B.A. Vick and G.J. Seiler, (2006). Performance of seven new cytoplasmic
male-sterile sunflower lines from induced mutation and a native American variety. Helia,
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Kinman, M.L., (1970). New developments in the USDA and state experiment station sunflower
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Leclercq, P., (1969). Une sterilite male cytoplasmique chez le tournesol. Ann. Amelior. Plant.,
19: 99-106.
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restoration de la fertilite. Ann. Amelior. Plant., 21: 45-54.
Petrov, A. and N. Nenov, (1992). Characteristics of some new CMS sources of the
genus helianthus. Helia, 15: 49-52.
Serieys, H., (2002). Identification, study and utilization in breeding programs of new CMS
sources, in FAO Subnetwork. Proceedings of Sunflower Subnetwork Progress Report FAO
Rome Italy 7-9 October.
Spirova, M., (1990). Genetic nature of male sterility in sunflower from a source of cultivated
sunflower. Comptes Rendus de I’ Academie Bulgare des Sci., 43: 113-116.
Vranceanu, A.V. and F.M. Stoenescu, (1971). Pollen fertility restorer gene from cultivated
sunflower (Helianthus annuus L.). Euphytica, 20: 536-541.
Whelan, E.D.P. and W. Dedio, (1980). Registration of sunflower germplasm composite crosses
CMG-1, CMG-2 and CMG-3. Crop Sci., 20: 832-832.
11. Table 2: Identification of inbred behavior for maintenance and restoration of diverse CMS
sources of sunflower
12. PET 1 (Helianthus petiolaris); R: Restorer; ARG (Helianthus argophyllus)., M: Maintainer; GIG
1 (Helianthus giganteus), Results are pooled observations of F1s (CMS x inbreds), from a
replicated experiment with three replications, for fertility reactions of inbreds
Modern sunflower breeding began with development of F1 hybrids after the discovery of
cytoplasmic male sterility (Leclercq, 1970) and fertility restorer genes (Kinmann, 1970). The
first reliable cytoplasmic male sterile source was isolated by Leclercq (1969) from the
interspecific cross Helianthus petiolaris Nutt. × Helianthus annuus and designated as PET-1
cytoplasm (Serieys, 1987).
Serieys, H.A., 1987. Genetic evaluation and use of Helianthus wild species and their use in
breeding programme. FAO Subnetwork Report, 1984-1986, pp. 1-23.
The pollen grains were uniformly plumpy and did not clump indicating the normal development
of pollen. The percentage of fertile pollen ranged from ……….in the F1 hybrids.
The percentage of stained pollen and or the percentage of typical aborted pollen should be used
as an essential index for determining plant fertility. Most research confirms that pollen fertility
could be a main criterion for assessing fertility. Percentage of fertile pollen was the most reliable
criterion for fertility (Hu, 1983).
Hu, Jinguo (1983). Exploratory research on the criterion used for studying the inheritance of
CMS in rice. J. Huazhong, Agric. Coll., 2(3):
Main factors affecting fertility restoration:
Genetic diversity: Genetic diversity includes differences in sterile cytoplasm and backgrounds of
maintainers and restorers. Isogenic male sterile (MS) lines with different sterile cytoplasms may
belongs to different sterile types and have different restorers.
13. The genetic background of maintainers influences the fertility of F1 hybrids having the same
sterile cytoplasm. For example, fertility restoration of WA type MS line Zhe-Shan-97A was
easier than of WA type Er-Jiu-Nan-1A (Li and Yiao, 1982).
The genetic background of restorers apparently influences fertility restoration. When restorer IR-
24, IR-26, IR-28 and Gu-154 were crossed with the same male sterile (MS) line, the fertility of
F1 hybrids revealed that the restorers differed in fertility restoring ability. Especially under
unfavorable climate, the seed setting rate of hybrids derived from IR-28 and Gu-154 was lower
than the hybrid derived from IR-24.
Environmental variation: Environmental factors, particularly temperature, greatly influence
fertility restoration. Seed setting rate may be drop when unfavorably high or low temperature
occurs during the pollen mother cell meiosis stage or heading stage. Chinese research showed
that temperature and moisture affect fertility restoration. Hybrids derived from different MS lines
and restorers differ in their reactions to environmental variations (Li and Yiao, 1982).
Li, Zebing and Yiao, Yihua (1982). Hybrid rice research and practice. Shanghai Technological
Press, China.
This variation among male-fertility-restored plants may be due to genetic background or
environmental factors such as high temperatures at critical times of flower development (Barham
and Munger, 1950; Meer and Bennekom, 1969).
Barham, W.S. and H.M. Munger. (1950). The stability of male sterility in onion. Proc. Amer.
Soc. Hort. Sci. 56 : 401–409.
Meer, Q.P. and J.L. Bennekom. (1969). Effect of temperature on the occurrence of male sterility
in onion (Allium cepa L.). Euphytica, 18 : 389–394.
Similar variation was found in the Tournefortii male sterility of rapeseed (Brassica
napus), in which some genotypes showed different degrees of male-fertility-restoration and were
explained as interactions with genetic background (Pahwa et al., 2004).
14. Pahwa, R.S., S.K. Banga, K.P.S. Gogna, and S.S. Banga. 2004.Tournefortii male sterility system
in Brassica napus. Identification, expression and genetic characterization of male fertility
restorers. Plant Breed. 123 : 444–448.
Environmental factors (such as nutritional and water deficiencies or high temperatures), pests
(insects or diseases), and/or other genetic factors could affect pollen production (Barham and
Munger, 1950; Delph et al., 2007; Monosmith, 1928). Barham and Munger (1950) studied
temperature effects on pollen production in S-cytoplasmic male-sterile lines and found that high
temperatures after emergence of scapes increased the amount of viable-appearing pollen;
however, no selfed seeds were produced on these S-cytoplasmic plants. In chive (Allium
schoenoprasum), a restorer locus has been reported that produces viable pollen at high
temperatures (Engelke et al., 2004).
Delph, L.F., P. Touzet, and M.F. Bailey. (2007). Merging theory andmechanism in studies of
gynodioecy. Trends Ecol. Evol. 22 : 17–24.
Monosmith, H.R. (1928). An investigation of the histological development and inheritance of
male sterility in a clone of Allium cepa L. PhD Diss., Univ. California, Berkeley.
Engelke, T., D. Gera, and T. Tatlioglu. (2004). Determination of the frequencies of restorer- and
maintainer-alleles involved in CMS1 and CMS2 in German chive varieties. Plant Breed.
123 : 51–59.
There is an improved understanding of the importance of a balance between genes for pollen
fertility restoration in male parent and fertility enhancing genes that affect the case of
restoration in the female. It may be possible to identify CMS female that exhibit partial
fertility in a favourable (Shallow sterile) environment. Such lines in hybrid combination
may interact with restorer genes to provide a highly fertile hybrid that is stable over a range
of climatic conditions.
Restoration is also influenced by environmental conditions, with cool conditions around
flowering favoring sterility and high temperatures favouring fertility (Downs and Marshall 1971;
Brooking 1976, 1979).
15. Brooking IR (1976) Male sterility in Sorghum bicolor (L.) Moench induced by low night
temperature. I. Timing of the stage of sensitivity. Aust. J. Plant Physiol., 3 : 589–596.
Brooking IR (1979) Male sterility in Sorghum bicolor (L.) Moench induced by low night
temperature. II. Genotypic differences in sensitivity. Aust. J. Plant Physiol., 6 : 143–147.
Downs RW, Marshall DR (1971) Low temperature induced male sterility in grain sorghum. Aust.
J. Agric. Res. Animal Husb., 11: 352–356.
Do you consider that different cytoplasm require entirely different sets of restoring genes (yes).
Restorers of one CMS line were found to be maintainers of other CMS lines and vice versa, it
can be concluded that specific restorer genes exist for a specific cyto-sterility system.
However, it is possible that certain restorer lines would restore the fertility of two different
cytosterile lines because they posses restorer genes for the two cytosterility systems.
Have you observed any environmental conditions (or plant growth regulators) that will restore
pollen fertility in CMS lines
Ans. For stable CMS lines, we have found none. For unstable A lines, there may be.
16. Figure 1. A). All stained pollen (Complete restorer). B). 50% unstained pollen (Partial restorer)
C&D). All unstained pollen (Maintainer), and E). 50% stained pollend (Partial restorer)
A. CMS-234A x RHAGKVK-2 B. CMS-10A x AKSFI-46-2
B. IMS-852A x IB-61 D. IMS-852A x AKSFI-49-3
E. CMS-10A x AKSFI-46-2 (Partial restorer)
B. 50% unstained pollenA. All stained pollen
C. All unstained pollen D. All unstained pollen
E. Unstained pollen
17. Table 3: Classification of F1 population based on pollen fertility in sunflower
S. No. Class Pollen fertility per cent
1 Fertile > 80
2 Partially fertile 50.1-80
3 Partially sterile 1.1-50
4 Sterile 0
18. Step 1. (10,000 to 15,000)
5000 - 8000
Individual plant
selections
Based on uniform maturity, plant
height, head shape, size, seed filling
ability
Oil and hull analysis.
1,000-1,200 heads
Selected for first year nursery
(2RRT)
Step 2. First year nursery (Progeny row trial) Aportion of seed Kept as reserve
C C C C C C
Agronomic, seed quality, disease
and seed yield, oil content
evaluation, 150-200 heads selected
for second year nursery.
Second year nursery (Remant seeds used)
C C C C C C
Second year evaluation of
characters. 20-50 heads selected for
cross pollination nursery
Cross-pollination nursery Seeds from Cross-pollination
nursery are used for preliminary
and competitive strain testing
Best families IP harvested separetely, Lab Analysis
Best plants retained Remaining seeds
for next breeding cycle bulked family wise
(Isolation)
Preliminary strain testing Preliminary increase of best
cultivars conducted on the basis of
competitive testing
Competitive cultivars
testing
State cultivar testing
Diagram of pustovoit “ Method of Reserves” for improvement of sunflower cultivars.
Superior
cultivars
populations
or hybrids
19. Table 1. Mapping of fertility restorer genes in sunflower
Trait Gene/locus Linkage group
(LG)
Population/s, line/s References
Pollen fertility
restoring genes
Rf1 LG 13 HA89 x RHA266,
CX x RHA266,
PAC2 x RHA266
Gentzbittel et al. 1995, 1999
msc1 LG 7 CP73 x PAC1,
GH x PAC2
Gentzbittel et al. 1995, 1999
msc1 LG P GH x PAC2 Mestries et al. 1998
Rf1 LG 13 RHA325 x HA342 Horn et al. 2003;
Kusterer et al. 2005
Rf3 LG7 RHA340 x ZENB8 Abratti et al. 2008
Rf1 LG13 RHA439 x
cmsHA441
1. Yue et al. 2010
Rf6 LG3 - 2. Liu et al. 2013
3.
Liu, Z., Wang, D., Feng, J., Seiler, G.J., Cai, X.and Jan, C.C. (2013). Diversifying sunflower
germplasm by integration and mapping of a novel male fertility restoration gene. Genetics,
193(3): 727-237.
Yue, B., Vick, B.A., Cai, X. and Hu, J. (2010). Genetic mapping for the Rf1 (fertility restoration)
gene in sunflower (Helianthus annuus L.) by SSR and TRAP markers. Plant Breeding,
129(1): 24-28.
Gentzbittel, L., Vear, F., Zhang, Y.X., Bervillé, A. nad Nicolas, P. (1995). Development of a
consensus linkage RFLP map of cultivated sunflower (Helianthus annuus L.). Theor Appl
Genet 90: 1079–1086.
Gentzbittel, L., Mestries, E., Mouzeyar, S., Mazeyrat, F., Badaoui, S., Vear, F., Tourvieille de
Labrouhe, D., Nicolas, P. (1999). A composite map of expressed sequences and phenotypic
traits of the sunflower (Helianthus annuus L.) genome. Theor Appl Genet 99: 218–234.
Mestries, E., Gentzbittel, L., Tourvieille de Labrouhe, D., Nicolas, P. and Vear, F. (1998).
Analyses of quantitative trait loci associated with resistance to Sclerotinia sclerotiorum in
sunflower (Helianthus annuus L.) using molecular markers. Mol Breed 4: 215–226.
20. Horn, R., Kusterer, B., Lazarescu, E., Prüfe, M. and Friedt, W. (2003). Molecular mapping of the
Rf1 gene restoring pollen fertility in PET1-based F1 hybrids in sunflower (Helianthus
annuus L.). Theor Appl Genet 106: 599–606.
Kusterer, B., Horn, R. and Friedt, W. (2005). Molecular mapping of the fertility restoration locus
Rf1 in sunflower and development of diagnostic markers for the restorer gene. Euphytica
143: 35–42.
Abratti, G., Bazzalo, M.E. and León, A. (2008). Mapping a novel fertility restoration gene in
sunflower. Proc 17th Int Sunflower Conf, vol 2, Córdoba, Spain, pp 617–621.
Fertility restoration of dominant nuclear genes is essential for hybrid breeding based on CMS to
obtain high yields of seeds. One to four dominant restorer genes have been described depending
on the material (Serieys 1996). However, in most of the elite sunflower lines, the two dominant
nuclear genes Rf1 and Rf2 are responsible for fertility restoration (Leclercq 1984). As Rf2 is
present in nearly all inbred lines, including maintainers of CMS, the Rf1 gene is most important
for sunflower hybrid breeding. Molecular markers linked to different fertility restoration genes
have been identified, and some of these genes have been mapped to LG 13 (Rf1, for PET1
cytoplasm from H. petiolaris) and to LG 7 (Rf3) (Gentzbittel et al. 1995; Horn et al. 2003; Yu et
al. 2003, Hamrit et al. 2006b; Abratti et al. 2008). Identifying molecular markers tightly linked to
this gene will be useful in marker-assisted selection to develop maintainer and restorer lines.
Hamrit S, Engelmann U, Schnabel U, Warber D, Kurutz S, Kusterer B, Lazarescu E, Özdemir N,
Friedt W, Abratti G, Leon A, Horn R (2006b) Comparative mapping of restorer genes
restoring pollen fertility in the presence of different CMS cytoplasms in the genus
Helianthus. In: Proc 7th Eur Conf Sunflower Biotechnol, 3–6 Sept 2006, Gengenbach,
Germany, p 10.
Yu JK, Tang S, Slabaugh MB, Heesacker A, Cole G, Herring M, Soper J, Han F, Chu WC,
Webb DM, Thompson L, Edwards KJ, Berry ST, Leon A, Olungu C, Maes N, Knapp SJ
(2003) Towards a saturated molecular genetic linkage map for cultivated sunflower. Crop
Sci 43: 367–387.
Leclercq, P. (1984). Identification de gènes de restauration de fertilité sur cytoplasms stérilisants
chez le tournesol. Agronomie 4: 573–576.
21. Gundaev, A.I. (1971). Basic principles of sunflower selection. In: Genetic Principles of Plant
Selection. (In Russian). Nauka, Moscow, USSR, pp 417–465.
Nuclear male sterility (NMS) in sunflower was first discovered by Kuptsov in 1934
(Gundaev 1971).
Cytoplasmic male sterility (CMS) and its fertility restoration (Rf) genes are critical tools
for hybrid seed production to utilize heterosis. To produce the hybrid seeds, the CMS plants are
crossed with restorer lines that have the Rf1 (restorer of fertility) gene to obtain fertile plants.
The ability of molecular markers linked to this locus facilitates the introgression of this gene in
different lines of breeding programs for developing new restorer lines.
The two most important developments were the dramatic increase in seed oil percentage
achieved by breeders in the former Soviet Union (FSU), and the development of a cytoplasmic
male sterility system, combined with fertility restoration by nuclear genes, which enabled the
commercial production of hybrid seed (see for review, Fick and Miller 1997).
Alternative CMS/Rf gene systems could expand the diversity of the sunflower crop, and reduce
the risks inherent with using a single CMS/Rf system. Also, identification and characterization of
additional CMS/Rf gene systems will enrich knowledge of the interactions between cytoplasm
and nuclear genes.
Screening elite breeding lines for effective and genetically diverse maintainers and
restorers for different CMS lines is important in developing new CMS lines and productive
hybrids. The success of hybrids based on new cytoplasm depends not only on restoration ability
but also on the nuclear genes for exploitation of heterosis.
A high percentage of pollen fertility restoration, stable restoring ability over
locations/season, and good combining ability are the important key attributes needed to ensure
commercially viable hybrid technology. For developing new cytoplasmic male sterile (CMS)
lines, it is important to screen the locally adapted elite breeding lines for genetically diverse
maintainers and promising restorers with wide genetic base for developing commercial hybrids.
22. The diversification of CMS sources may also be useful to optimize the utilization of
genetic resources in breeding programs by “changing’ the restorer status of an inbred line (i.e., a
restorer genotype of one cytoplasm may be a male sterility maintainer of a second one).
All the CMS sources utilized in the experiment showed diversity among themselves, thus
broadening the genetic base of the CMS lines, which could be safely included in breeding
programme thereby mitigating the vulnerability of the lines to various insect pests and diseases.
Actually, research efforts for developing heterotic groups with high yields and reduced
genetic vulnerability to ever changing environmental stress and diseases are often jeopardized
due to lack of alternative CMS and the associated restorers.
The PET-1 cytoplasm controlling sterility has no apparent adverse effects on agronomic
or seed oil characteristics (Velkov and Stoyanova, 1974), and has proven widely successful in
production of hybrid seed. However, suitable fertility restorers are not available for all of these
sources and several sources have negative effects on seed yield, and other plant and seed
characteristics (Petrov, 1992a; Serieys, 1992; Havekes et al., 1991).
Velkov, V. and Stoyanova, Y. (1974). Biological peculiarities of cytoplasmic male sterility and
schemes of its use. P. 361-365. In Proc. 6th
Int. Sunflower Conf., Bucharest, Romania, 22-
24 July. Int. Sunflower Assoc., Paris, France.
Serieys, H. (1992). Cytoplasmic effects on some agronomical characters in sunflower. P. 1245-
1250. In Proc. 13th
Int. Sunflower Conf., Pisa, Italy, 7-11 September. Int. Sunflower
Assoc., Paris, France.
Petrov, P. (1992a). Effect of various cytoplasmic male sterility sources (CMS) on some
sunflower qualities. P. 1211-1215. In Proc. 13th
Int. Sunflower Conf., Pisa, Italy, 7-11
September. Int. Sunflower Assoc., Paris, France.
Havekes, F.W.J., Miller, J.F. and Jan, C.C. (1991). Diversity among sources of cytoplasmic male
sterility in sunflower (Helianthus annuus L.). Euphytica, 55: 125-129.