Phenotype is a result of genotype, environment and GE interaction. GENOTYPE- environment interactions are of major
importance to the plant breeder in developing
improved varieties. The performance of a single variety is not the same in all the environments. To identify a genotype whose performance is stable across environments various models were proposed. One such model was proposed by EBERHART and RUSSELL in 1966. Even after decades, this model is still preferred over others and used till date for stability analysis.
Stability analysis and G*E interactions in plantsRachana Bagudam
Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. Stability refers to the performance with respective to environmental factors overtime within given location. Selection for stability is not possible until a biometrical model with suitable parameters is available to provide criteria necessary to rank varieties / breeds for stability. Different models of stability are discussed.
Stability refers to the performance with respective changing environmental factors overtime within given location.
Selection for stability is not possible until a biometrical model with suitable parameters is available to provide criteria necessary to rank varieties / breeds for stability.
The presentation was done as part of the course STAT 504 titled Quantitative Genetics in Second Semester of MSc. Agricultural Statistics at Agricultural College, Bapatla under ANGRAU, Andhra Pradesh
Power Point is deals with the different aspects of Quantitative genetics in plant breeding it converse Basic Principles of Biometrical Genetics, estimation of Variability, Correlation, Principal Component Analysis, Path analysis, Different Matting design and Stability so on
Stability analysis and G*E interactions in plantsRachana Bagudam
Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. Stability refers to the performance with respective to environmental factors overtime within given location. Selection for stability is not possible until a biometrical model with suitable parameters is available to provide criteria necessary to rank varieties / breeds for stability. Different models of stability are discussed.
Stability refers to the performance with respective changing environmental factors overtime within given location.
Selection for stability is not possible until a biometrical model with suitable parameters is available to provide criteria necessary to rank varieties / breeds for stability.
The presentation was done as part of the course STAT 504 titled Quantitative Genetics in Second Semester of MSc. Agricultural Statistics at Agricultural College, Bapatla under ANGRAU, Andhra Pradesh
Power Point is deals with the different aspects of Quantitative genetics in plant breeding it converse Basic Principles of Biometrical Genetics, estimation of Variability, Correlation, Principal Component Analysis, Path analysis, Different Matting design and Stability so on
Association mapping, also known as "linkage disequilibrium mapping", is a method of mapping quantitative trait loci (QTLs) that takes advantage of linkage disequilibrium to link phenotypes to genotypes.Varioius strategey involved in association mapping is discussed in this presentation
It comprises on mating designs used in plant breeding programs. 6 basic mating designs are briefly explained in it with their requirements as well limiting factors...
GGEBiplot analysis of genotype × environment interaction in Agropyron interme...Innspub Net
In order to identify genotypes of Agropyron intermedium with high forage yield and stability an experiment was carried out in the Research station of Kermanshah Iran.The 11 accessions were sown in a randomized complete block design with three replications under rainfed and irrigated conditions during 2013-21-014 cropping deasons. Combined analysis of variance indicated high significant differences for location, genotype and G × E interaction (GEI) at 1% level of probability. Mean comparisons over environments introduced G4, G3 and G5 with maximum forage yield over rainfed and irrigated conditions. Minimum forage yield was attributed to genotype G1. GGEbiplot analysis exhibited that the first two principal components (PCA) resulted from GEI and genotype effect justified 99.37% of total variance in the data set. The four environments under investigation fell into two apparent groups: irrigated and rainfed. The presence of close associations among irrigated (E1 and E3) and rainfed (E2 and E4) conditions suggests that the same information about the genotypes could be obtained from fewer test environments, and hence the potential to reduce testing cost.The which-won-where pattern of GGEbiplot introduced genotypes G3 and G4 as stable with high forage yield for rainfed condition, while G5 was stable with high yield for irrigated condition. According to the comparison of the genotypes with the Ideal genotype accessions G4, G3 and G9 were more favorable than all the other genotypes. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Advanced biometrical and quantitative genetics akshayAkshay Deshmukh
Additive and Multiplicative Model
Shifted Multiplicative Model
Analysis and Selection of Genotype
Methods and steps to select the best model
Bioplot and mapping genotype
Association mapping, also known as "linkage disequilibrium mapping", is a method of mapping quantitative trait loci (QTLs) that takes advantage of linkage disequilibrium to link phenotypes to genotypes.Varioius strategey involved in association mapping is discussed in this presentation
It comprises on mating designs used in plant breeding programs. 6 basic mating designs are briefly explained in it with their requirements as well limiting factors...
GGEBiplot analysis of genotype × environment interaction in Agropyron interme...Innspub Net
In order to identify genotypes of Agropyron intermedium with high forage yield and stability an experiment was carried out in the Research station of Kermanshah Iran.The 11 accessions were sown in a randomized complete block design with three replications under rainfed and irrigated conditions during 2013-21-014 cropping deasons. Combined analysis of variance indicated high significant differences for location, genotype and G × E interaction (GEI) at 1% level of probability. Mean comparisons over environments introduced G4, G3 and G5 with maximum forage yield over rainfed and irrigated conditions. Minimum forage yield was attributed to genotype G1. GGEbiplot analysis exhibited that the first two principal components (PCA) resulted from GEI and genotype effect justified 99.37% of total variance in the data set. The four environments under investigation fell into two apparent groups: irrigated and rainfed. The presence of close associations among irrigated (E1 and E3) and rainfed (E2 and E4) conditions suggests that the same information about the genotypes could be obtained from fewer test environments, and hence the potential to reduce testing cost.The which-won-where pattern of GGEbiplot introduced genotypes G3 and G4 as stable with high forage yield for rainfed condition, while G5 was stable with high yield for irrigated condition. According to the comparison of the genotypes with the Ideal genotype accessions G4, G3 and G9 were more favorable than all the other genotypes. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Advanced biometrical and quantitative genetics akshayAkshay Deshmukh
Additive and Multiplicative Model
Shifted Multiplicative Model
Analysis and Selection of Genotype
Methods and steps to select the best model
Bioplot and mapping genotype
A computer consists of four major parts: the input, output, CPU (central processing unit), and memory. Input consists of anything you will add into the computer (microphone, keyboard, mouse, scanner), and output is how the computer gives back to you (think screen, speakers, etc.). The CPU or central processing unit is located on the motherboard and is the part of the computer where all that input/output information gets sent to the proper place. Memory, commonly referred to as RAM (random access memory), as you may already know, is where the information is stored.
CONTENTS
Data representation in computers
Computer memory and Storage
Input and Output media
Current trends in computer
PRESENT STATUS AND FUTURE STRATEGIES IN COLLECTION OF MAJOR CROPS OF COTTON, ...Dhanuja Kumar
Cotton has played a great role in the global and Indian economies since immemorial time. The antiquity of cotton in the Indian subcontinent has been traced to the 4th millennium BC.
The wild species of Gossypium are important sources of useful traits such as special and superior fibre properties, cytoplasmic male sterility, resistance to biotic and abiotic stresses etc. which can be introgressed into the cultivated species for improvement. Since the variability available in cultivated germplasm is limited and has been exhaustively utilized in breeding programmes, it has become a necessity to collect, conserve and develop basic germplasm materials enriched with rare useful genes.
Conservation is very important in mango, because many species are becoming extinct and many others are threatened and endangered.
Heat stress as well as other stresses can trigger some mechanisms of defense such as the obvious gene expression that was not expressed under “normal” conditions.
The sudden changes in genotypic expression resulting in an increase in the synthesis of protein groups. These groups are called “heat-shock proteins” (Hsps), “Stress-induced proteins” or “Stress proteins”
Nucleic acid and its chemistry - DNA, RNA, DNA as genetic materialDhanuja Kumar
The nucleic acids are vital biopolymers found in all living organisms, where they function to encode, transfer, and express genes. The nucleic acids are of two types, namely deoxyribonucleic acid (DNA) and ribonucleic acid(RNA)
PREPARING CHEMICAL SOLUTIONS – MEASURING AND HANDLING SOLID CHEMICALS - MEASU...Dhanuja Kumar
Lab experiments and types of research often require preparation of chemical solutions. Preparations of these chemical solutions are done by weight (w/v) and by volume (v/v).
Breeding for nutritional quality in pulsesDhanuja Kumar
Legumes have been part of the human diet since the early ages of agriculture. Legumes are consumed in many forms: seedling and young leaves are eaten in salads, fresh immature pods and seeds provide a green vegetable, and dry seeds are cooked in various dishes. Legume seeds provide an exceptionally varied nutrient profile, including proteins, fibres, vitamins and minerals.
Breeding for nutritional quality entails an improvement primarily in protein quantity and quality which are of paramount significance.
PROBLEMS AND PROSPECTS OF BREEDING FOR NUTRITIONAL QUALITY
• Negative correlation between yield and protein content.
• Negative correlation between protein and sulphur containing amino acids
• Lack of proper field screening technique.
Terminator gene technology refers to plants that have been genetically modified to render sterile seeds at harvest.
Genetic use restriction technologies (GURTs) are the name given to experimental methods, described in a series of recent patent applications and providing specific genetic switch mechanisms that restrict the unauthorized use of genetic material (FAO, 2001a) by hampering reproduction (variety-specific V-GURT) or the expression of a trait (trait-specific T-GURT) in a genetically modified (GM) plant.
Breeding rice for sustainable agricultureDhanuja Kumar
Rice is the major cereal crop in Asia where 90% of the world’s rice is produced and consumed. Rice production and productivity need to keep pace with a growing global population likely to reach 9 billion by 2050 in order to have a hunger-free world and to ensure sustainable production in the face of depleting resources such as land, water and nutrients as well as changing climatic conditions.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
2. STABILITY ANALYSIS
• The phenotype of an individual is determined by the effects of
its genotype and environment surrounding it.
• The interplay in the effect of genetic and non-genetic on
development is termed as 'genotype-environment interaction'.
• P=G+E+GE
3. GE INTRACTION
• GENOTYPE- environment interactions are of major importance
to the plant breeder in developing improved varieties.
• When varieties are compared over a series of environments, the
relative rankings usually differ. This causes difficulty in
demonstrating the significant superiority of any variety.
• Large genotype-environment interactions reduce the progress
from selection (Comstock and Moll )
4. STRATIFICATION
• Stratification of environments has been used effectively to
reduce the genotype-environment interaction.
• This stratification usually is based on macro-environment
• Even with this, the interaction of genotypes in a subregion, and
with environments at the same location in different years,
remains too large.
• Allard and Bradshaw classify as unpredictable the
environmental variation, for which stratification is not effective.
5. STRATIFICATION
• Select stable genotypes that interact less with the environments
in which they are to be grown. If stability of performance,
(minimum of interaction with the environment), is a genetic
characteristic, then preliminary evaluation could be planned to
identify the stable genotypes.
• With only the more stable genotypes remaining for the final
stages of testing, the breeder would be greatly aided in his
selection of superior genotypes.
• However, selection for stability is not possible until a model
with suitable parameters is available to provide the criteria
necessary to rank varieties for stability.
6. SUGGESTIONS TO REDUCE GEI
• The use of genetic mixtures rather than homogeneous or pure-lines
• Multiline variety (Jensen)
• Heterozygous and Heterogeneous populations (Allard and Bradshaw)
• They used the term "individual buffering" (each member of the
population is well adapted to a range of environments), and
"population buffering" (variety consists of a number of genotypes
each adapted to a different range of environments).
• Heterozygous or homozygous genotype may possess individual
buffering
• Heterogeneous population will possess population buffering.
7. • Double crosses interact with environments less than single
crosses. Double crosses are superior to single crosses for
stability (Sprague and Federer)
• Hybrid x Year interactions were significantly greater for single
crosses than for three-way crosses (Eberhart, Russell, and
Penny)
• Some single crosses may show more, phenotypic stability than
the most stable three-way or double cross. Because the variance
of a mean is less than the variance of an individual, the average
genotype-environment interaction of a mixture may be
expected to be less than the interaction for a single genotype.
8. STEPS IN STABILITY ANALYSIS
Done from replicated data over several environments
1. Environment wise analysis of variance
• Following usual method of analysis of variance, the data are
analyzed for a quantitative trait in all the environments
separately. The data of environments, where significant
difference for genotypes are observed, are used for pooled
analysis.
9. • Before proceeding to pooled analysis, the test of homogenity of
variances (Bartlets‘ chi square test) is to be done for the
environments.
• If the X2 value is non-significant, there is homogeneity of
variance among the environments. Hence, pooled analysis can
be carried out.
• In case, the X2 value is significant, it can be concluded that
there is heterogenity of variances among the environments
• If the error variances are heterogeneous, divide each value by
square root of corresponding mean square of error variance and
use for the combined analysis.
10. 2. POLLED ANALYSIS OF VARIANCE
• A two way table is formed
for tabulating the data of
genotypes in different
environments.
• If GE interaction is non-
significant, no need to
proceed further
• If significant, estimate
phenotypic stability.
Geno
types
E1 E2 …….. En
1
2
:
:
n
11. MODELS FOR STABILITY ANALYSIS
A. Conventional models
Stability factor model
(Lewis 1954)
Ecovalence model
(Wricke 1964)
Stability variance model
(Shukla 1972)
Lin and Binns model
(198)
B. Regression coefficient model
Finlay and Wilkinson model
(1963)
Eberhart and Russell model
(1966)
Perkins and Jinks model
(1968)
Freeman and Perkins model
(1971)
Genotypic stability model
(Tai 1971)
12. • C. Principle component
analysis
• Perkins (1972); Freeman
and Dowkar (1975); Seif
et al (1979)
• Additive main effect and
multiplicative interaction
effect
• Shifted multiplication
model
• Redundancy analysis
• Factor regression analysis
• GGE biplot
• D. Cluster analysis
Grouping by cluster
analysis (Westcot 1987)
Webber and Wricke (1990)
• E. Pattern analysis
Mungomery et al 1974
Delacy et al (1990)
• F. Factor analysis
Johnson and Wichern
(1982)
Calinski et al (1987)
13. REGRESSION COEFFICIENT MODEL
• For phenotypic stability analysis, regression analysis has proved
to be valuable for assessing response under changing
environments.
• The regression of each variety in an experiment on an
environmental index and a function of the squared deviations
from this regression would provide estimates of the desired
stability parameters
14. EBERHART AND RUSSELL (1966)
In 1966, Eberhart and Russell (1966) made further improvement
in stability analysis.
Three parameter model
1. Mean yield over locations or seasons
2. Regression coefficient (b)
3. Deviation from regression (s2
d)
15. PARTITION
Total variance
1. Genotypes
2. Environment + interaction (E + G × E)
1. Environment (linear)
2. G × E (Linear)
3. Pooled deviations
Sum of square due to pooled deviations is partitioned in to sum
of square due to individual genotype
16. The model considered by Eberhart and Russell may be written as
yij = μi + bi Ij + δij
• yij - Mean of ith variety in jth environment
• μi - Mean of all varieties over all environments
• bi - Regression co-efficient of ith variety on environmental index
which measures the response of this variety to varying environments
• Ij - Environmental index i.e. the deviation of the mean of all the
varieties at a given environment from the over all mean
• δij - The deviation from regression of ith variety at jth environment
17.
18. MAIN FEATURES
• Analysis of stability is simple as compared to other models
• Degree of freedom for environment is 1
• Less expensive than Freeman and Perkins model
•It does not provide independent estimation for mean
performance and environmental index
• Stable genotype is one with bi = 1, s2
d = 0 and high mean yield
19. STABILITY PARAMETERS
• With this approach, the first stability parameter is a
regression coefficient, bi which can be estimated by
• The deviation can be squared and summed to provide
an estimate of another stability parameter, mean
square deviation
20. THE MODEL PROVIDES A MEANS OF
PARTITIONING THE GE INTERACTION OF EACH
GENOTYPE INTO TWO PARTS
The variation due to the response of genotype to
varying environmental indices (sums of square
due to regression)
The unexplainable deviation from regression on
the environmental indices.
21. STABLE GENOTYPE
1. A genotype with high/ desirable mean value
2. A genotype with deviation not significantly deviating
from 0 is stable
3. A genotype with unit regression coefficient
• average responsive suitable for all
environmentb=1
• highly responsive suitable for favourable
environmentb>1
• low responsive suitable for unfavourable
environmentb<1
22. • Further, they define that the stable variety will be one with bi =
1.0 and s2
d = 0; and the null hypothesis
H0 : μ1 = μ2 = … = μm (To test the significance among the genotype means)
can be tested by the F-test (approximately)
F = MG / Md (F=MS1/MS3)
with homogeneous deviation mean squares, being Md the
pooled deviations.
• The hypothesis that there are no genetic differences among
phenotypes for their regression on the environmental index
H0 : β1 = β2 = … = βm (To test if the varieties differ for their regression on EI)
can be tested by the F-test F = MEI / Md (F=MS2/MS3)
23. • The deviations from regression for each genotype can be
further tested by
• Thus, in this approach one can see that two measures of
sensitivity of the genotype to changes on environment are
worked out:
(i) the linear sensitivity measure in terms of the linear
regression coefficient, bi of the ith genotype to the
environmental change
(ii) the non linear sensitivity measure in terms of the
deviation from regression mean square
24. APPLICATION OF THE MODEL TO MAIZE
YIELD TRIALS
• Single crosses were grown in the Iowa State University
experimental yield trials for 1945-51.
• Data for a diallel set of single crosses from 11 lines
grown in 8 environments in 1945-47 and for a diallel
set frown 8 lines in 12 environments in 1948-51 were
extracted and analyzed.
26. PARTITION
• The differences among regression coefficients [SC x Env
(linear)] can be partitioned into General x Env (linear) and
Specific X Env (linear).
• Since the Specific X Env (linear) squares are not significantly
greater than the respective deviation mean squares, there is no
evidence that regression coefficients differ because of non
additive gene action.
• However, the General x Env (linear) mean squares were
significant (P ~ .05) for both diallels.
27. Differences in stability of 2 single crosses and their
performance in relation to average of the test
1.WF9 X M14 is a very
desirable hybrid because
its performance is
uniformly superior
b=1.06, s2
d = 0
2.M14 X B7 is expected to
equal or exceed average
performance only under
very unfavorable
conditions b=.76, s2
d=5
28. The vertical
lines are one
SD above and
below the GM,
whereas the
horizontal
lines are one
SD above and
below the
average slope
(b=1.0).
The relation of yield stability of 28 single crosses. Estimates
of s2
d were significant only for those hybrids indicated by +
29. • The single cross with above-average performance and
satisfactory stability in the 1945-47 diallel is WF9 x Oh28
• WF9 x M14 had above-average performance over environments,
but the estimate of s2
d was 30.
• In the 1948-51 diallel, two single crosses gave high yields with
stability WF9 x M14 and WF9 x W22
• The line Hy performed consistently better in favorable
environments (b = l.15 and 1.15), whereas O8420 performance
was relatively better in less favorable environments (b = .95 and
.55)
31. • Three-way crosses involving three single-cross testers and six inbreds
• The difference in the response of three-way crosses to varying
environments was due to the different responses of the lines as
indicated by the large Lines X Env (linear) mean square.
• Three-way crosses involving W22 performed much below average in
unfavorable environments, whereas N22A and B37 did extremely well
under less favorable conditions.
• The performance of B37 in three-way crosses was much more
predictable than hybrids involving B54 or B46, as indicated by the
estimates, s2
d
32. Analysis of 18 three way cross and three single
cross testers grown at 2 locations
34. PERFORMANCE OF THE TESTERS (SINGLE CROSSES)
COMPARED WITH THEIR AVERAGE TESTCROSS
PERFORMANCE (THREE-WAY CROSSES)
35. • None of the three-way crosses falling in the center section to the right
had a non significant deviation mean square. However, the hybrid
(WF9 x M14) N22A (x = 119.8, b = 1.05, s2
d = 41) is the most nearly
acceptable even though s2
d is larger than desirable.
• (WF9 X B14) B37 (x = 119.5, b — .74, s2
d — 0) would be especially good
under less favorable environments but not good under favorable
conditions. The hybrid with the highest mean yield (WF9 X M14) B37
is unacceptable for both stability parameters
36.
37. • Although the inbred lines of maize in this experiment differed in
their average responses to varying environments, the Variety X
Env (linear) sum of squares was not a very large proportion of
the Variety X Environmental interaction.
• Hence, the second stability parameter (s2
d) appears very
important.
• Because the variance of s2
d is a function of the number of
environments, several environments with minimum replication
per environment are necessary to obtain reliable estimates of s2
d.
• However, a good estimate of the regression coefficients can be
obtained from a few environments if they cover the range of
expected responses.
38. MERITS AND DEMERITS
• This model measures three parameters of stability, viz. (1) mean
yield over environments (2) regression coefficient and (3)
deviation from the regression line.
• This model provides more reliable information about varietal
stability than Finlay and Wilkinson model.
• The analysis is also simple. In this model, the estimation of
mean performance and environmental index is not
independent.
• There is combined estimation of S.S. for environments and
interactions, which is not proper.
39. REFERENCES
• Eberhart, S., and Russell, W.A., 1966, Stability parameters for
comparing varieties, Crop Sci., 6: 36–40
• Nadarajan N, Manivannan M, Gunasekharan M, Quantitative
genetics and biometrical techniques in plant breeding, kalyani
publishers, 253-260.