The study evaluated the effect of mean temperature, solar radiation, and photothermal quotient (PTQ) at anthesis and maturity stages of wheat grown under different environmental conditions provided by varying planting windows. Regression models were developed relating climate variables (temperature, radiation, PTQ) to wheat yield parameters (grains per square meter, grain weight, yield). Results showed temperature and PTQ at anthesis had direct relationships with yield parameters, while temperature at maturity had inverse relationships. Solar radiation at anthesis and maturity also had direct relationships with yield parameters. PTQ, representing the combined effect of temperature and radiation, had the strongest direct relationships with all yield parameters. This confirms PTQ is a key determinant of wheat yield under varying environmental conditions
Ecophysiological Yield Components In Wheat Cultivars Under Variable Phosphoru...Agriculture Journal IJOEAR
Abstract— Effects of P deficiency and interactions Cultivar x P available, on wheat yield and ecophysiological components were analysed, considering that the grain number m-2 is the product of the length of spike growth period, crop growth rate during this phase, the proportion of growth for spikes (partitioning) and spike fertility (grain number produced per unit of spike dry weight). Four cultivars with different strategy to generate yield (i.e. combinations of ecophysiological yield components) were compared with and without P fertilization, during two years in Azul, Buenos Aires, Argentina. The soil was moderately P deficient (7-9 mg P kg-1 soil) and P fertilization treatments (50 kg P ha-1) were established at sowing. P deficiencies affected yield and most of its components, the exceptions were: partitioning to spike, spike growth period and radiation use efficiency. The interaction Cultivar x P fertilization was not significant in all cases. The lack of interaction between cultivar and P level suggest that improvements in any crop physiological component will express in both, moderately deficiencies or high P environment.
Seasonal Dynamics of Arbuscular Mycorrhizal Fungi, Glomalin and Soil Properti...ijtsrd
To understand the ecological significance of arbuscular mycorrhizal fungal (AMF) associations in agroecosysytem, the host specific and seasonal dynamics of AMF and glomalin-related soil protein (GRSP) was investigated in agricultural fields of Nanded, Maharashtra State. Soil samples were collected from the rhizosphere of eight crop plants (Glycine max (L.) Merr., Saccharum officinarum L., Zea mays L., Cajanas cajan (L.) Millsp., Gossypium arboreum L., Triticum aestivum L., Sorghum vulgare Pers. and Cicer arietinum L.) in winter, summer and monsoon seasons respectively. Arbuscular mycorrhizal root infection and spore density of AMF peaked in monsoon and winter.The mean contents of total glomalin related soil proteins (T-GRSP) reached maximal values in summer. Spore density was highest in Zea mays L. Easily extractable glomalin related (EE-GRSP) and T-GRSP fractions were the highest in the rhizosphere of Cicer arietinum L. and Sorghum vulgare Pers. AMF root colonization and spore density was negatively correlated with K (P < 0.05; P < 0.01). T-GRSP fraction was positively correlated with edaphic factors (rhizosphere temperature, K and Fe content of soil) and negatively correlated with soil moisture (P < 0.01), AMF root colonization (P < 0.05) and spore density (P http://www.ijtsrd.com/biological-science/ecology/15727/seasonal-dynamics-of-arbuscular-mycorrhizal-fungi-glomalin-and-soil-properties-in-agroecosystems-of-nanded-district/ujwala-sheshrao-deepake
Effects of Light Intensity and Quality on Physiological Changes in Winter Ric...Agriculture Journal IJOEAR
Abstract— An investigation into the effects of low light (meanPPFD169-493Ms-1m-1), red light (meanPPFD657-843Ms-1m-1) and normal light (meanPPFD1061-1260Ms-1m-1) on physiological changes including yield attributes, nutritional status at Panicle initiation (PI), flowering and harvest stages in winter rice (genotype: Monoharsali) was carried out from 40 days after transplanting (DAT) to crop maturity under both pot and field conditions. There was reduction in available PPFD at flowering as compared to PI stage of the crop. The genotype exhibited significantly higher total dry matter (TDM) and lower leaf area index (LAI) values at normal light or red light than at reduced light situation. The bio-economical yield and harvest index (HI) under normal light exceeded those at low light regime. The yield attributes viz., number of panicles, number of field grains per panicle, 1000 grain weight (test weight), high density (HD) grains, potential 1000 grain weight and sink capacity were superior at normal or red light to low light condition. Higher the total carbohydrate contents in grains, higher were the sink capacity with the normal /red light illuminations at harvest stage. At PI stage, leaf nitrogen content was reduced by low light, but it increased at flowering stage significantly. Grain protein contents, under normal/red light exceeded its value at low light treatment. A positive correlation of most of the yield attributes with grain yield at normal/red light, and a negative correlation of these parameters were found at low light conditions.
Ecophysiological Yield Components In Wheat Cultivars Under Variable Phosphoru...Agriculture Journal IJOEAR
Abstract— Effects of P deficiency and interactions Cultivar x P available, on wheat yield and ecophysiological components were analysed, considering that the grain number m-2 is the product of the length of spike growth period, crop growth rate during this phase, the proportion of growth for spikes (partitioning) and spike fertility (grain number produced per unit of spike dry weight). Four cultivars with different strategy to generate yield (i.e. combinations of ecophysiological yield components) were compared with and without P fertilization, during two years in Azul, Buenos Aires, Argentina. The soil was moderately P deficient (7-9 mg P kg-1 soil) and P fertilization treatments (50 kg P ha-1) were established at sowing. P deficiencies affected yield and most of its components, the exceptions were: partitioning to spike, spike growth period and radiation use efficiency. The interaction Cultivar x P fertilization was not significant in all cases. The lack of interaction between cultivar and P level suggest that improvements in any crop physiological component will express in both, moderately deficiencies or high P environment.
Seasonal Dynamics of Arbuscular Mycorrhizal Fungi, Glomalin and Soil Properti...ijtsrd
To understand the ecological significance of arbuscular mycorrhizal fungal (AMF) associations in agroecosysytem, the host specific and seasonal dynamics of AMF and glomalin-related soil protein (GRSP) was investigated in agricultural fields of Nanded, Maharashtra State. Soil samples were collected from the rhizosphere of eight crop plants (Glycine max (L.) Merr., Saccharum officinarum L., Zea mays L., Cajanas cajan (L.) Millsp., Gossypium arboreum L., Triticum aestivum L., Sorghum vulgare Pers. and Cicer arietinum L.) in winter, summer and monsoon seasons respectively. Arbuscular mycorrhizal root infection and spore density of AMF peaked in monsoon and winter.The mean contents of total glomalin related soil proteins (T-GRSP) reached maximal values in summer. Spore density was highest in Zea mays L. Easily extractable glomalin related (EE-GRSP) and T-GRSP fractions were the highest in the rhizosphere of Cicer arietinum L. and Sorghum vulgare Pers. AMF root colonization and spore density was negatively correlated with K (P < 0.05; P < 0.01). T-GRSP fraction was positively correlated with edaphic factors (rhizosphere temperature, K and Fe content of soil) and negatively correlated with soil moisture (P < 0.01), AMF root colonization (P < 0.05) and spore density (P http://www.ijtsrd.com/biological-science/ecology/15727/seasonal-dynamics-of-arbuscular-mycorrhizal-fungi-glomalin-and-soil-properties-in-agroecosystems-of-nanded-district/ujwala-sheshrao-deepake
Effects of Light Intensity and Quality on Physiological Changes in Winter Ric...Agriculture Journal IJOEAR
Abstract— An investigation into the effects of low light (meanPPFD169-493Ms-1m-1), red light (meanPPFD657-843Ms-1m-1) and normal light (meanPPFD1061-1260Ms-1m-1) on physiological changes including yield attributes, nutritional status at Panicle initiation (PI), flowering and harvest stages in winter rice (genotype: Monoharsali) was carried out from 40 days after transplanting (DAT) to crop maturity under both pot and field conditions. There was reduction in available PPFD at flowering as compared to PI stage of the crop. The genotype exhibited significantly higher total dry matter (TDM) and lower leaf area index (LAI) values at normal light or red light than at reduced light situation. The bio-economical yield and harvest index (HI) under normal light exceeded those at low light regime. The yield attributes viz., number of panicles, number of field grains per panicle, 1000 grain weight (test weight), high density (HD) grains, potential 1000 grain weight and sink capacity were superior at normal or red light to low light condition. Higher the total carbohydrate contents in grains, higher were the sink capacity with the normal /red light illuminations at harvest stage. At PI stage, leaf nitrogen content was reduced by low light, but it increased at flowering stage significantly. Grain protein contents, under normal/red light exceeded its value at low light treatment. A positive correlation of most of the yield attributes with grain yield at normal/red light, and a negative correlation of these parameters were found at low light conditions.
Journal of The Earth Science and Climate Change is a peer reviewed academic journal that cater to the needs of Earth Scientists, farmers, extensive agents, researchers and students. This Open access journal publishes high quality articles following rigorous and standard review procedure.
Numerical simulation of biodiversity: comparison of changing initial conditio...IJAEMSJORNAL
This study examined the effect of varying the initial value of industrialization for a fixed length of growing season on the prediction of biodiversity loss. We have found that when the initial value of industrialization is 0.1 under a shorter length of growing season, a relative low due of biodiversity loss can be maintained. The biodiversity loss value can be further lowered by maintaining the same length of growing season but with a reduced initial value of industrialization to 0.01 or 0.02. We would expect this alternative result to provide a further insight into our fight against biodiversity loss which has both human and sustainable development devastating effects.
Germination percentage and growing behavior of Salix tetrasperma (Willow) as ...Innspub Net
Propagation through branch cuttings is one of the best methods to produced tree nursery the yield of the tree produced from a cutting can be higher then a tree produced from seedlings, the conditions provided to them are important factor for getting good results. The aim of this study was to find the best size of cuttings for establishment of nursery and also to compare their performance in open air or in artificial conditions under plastic sheets cuttings of 2 inches, 4 and 6 of Salix tetrasperma were raised in plastic bags of size 3x7 their were three treatments with 25 bags in each and replicated 4 times. The data on sprouting percentage, plant height, root development etc was recorded after every two weeks. The data thus collected was analyzed statically using randomized complete block design. Result showed that cutting of 2 inches has high sprouting percentage and growth behavior as compared to other cuttings. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Food Security Production Challenges in Indonesia as Impact of Global Climate ...Agriculture Journal IJOEAR
— Global food availability, including national as well as local, is highly dependent on the natural resources that will affect crop production. Although there is rain, soil temperatures and conditions have formed a natural system that will support agricultural efforts, but this state is unstable and always changes according to atmospheric conditions in an integrated manner. Human beings on certain boundaries can intervene with the natural resources. Climate (generally a combination of rain, temperature, and sunlight) is the most important growth factor in crop production in the field. Any change in climatic conditions will have far-reaching effects on global food production. Global climate change, excessive land and land exploitation, inaccurate land management, in its time will have an impact on the food production and availability of a region. Knowing well the of nature characteristics, then anticipating the impact that will arise and determine the ways of handling it, is a series of business and activities that must be done to achieve food security. To anticipate climate change and its impacts on crop production, a broad outline can be made by considering the following physical technic aspects: 1) adjusting cropping patterns; 2) increasing the area of forest cover and catchment areas; 3) application of land and crop management technology. Some application of land and crop management technologies include: organic farming, implementation of Surjan system, food diversification, large tree planting, water pond production, etc. The policies that need to be taken as a solution in anticipating the impact of global climate change are 1) the preparation and stipulation of special food agriculture scenarios, including the zoning of production potential and zonation of climate risk (drought, flood, landslide, etc.) with the updating of data every year; 2) reducing the conversion of agricultural land (food); 3) incentives for farmers; 4) changing the consumption pattern of the people, from the consumption of rice to alternative staple foods; 5) subsidies and protection of food farming; 6) climate monitoring and prediction (early rainy season, long growing period, and potential water availability; 7) Revitalization of watershed (DAS) functions; 8) Multiply the artificial water absorption area.
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/
Effect of minimum tillage and Mulching on nutrient Transformation in rice bas...P.K. Mani
Paper presented at PAU, LUdhiana, 2012 describing nutrient transformation in rice based cropping system following zero tillage vs conventional tillage.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Aboveground to root biomass ratios in pea and vetch after treatment with orga...GJESM Publication
Some growth parameters of pea (cv. Pleven 4) and vetch (cv. Obrazets 666) after treatment with organic fertilizer were studied in a field trial carried out at the Institute of Forage Crops, Pleven, Bulgaria. Humustim as
organic fertilizer was applied through presowing treatment of seeds, treatment during vegetation and combination
between both, at different doses. Ratios of aboveground weight to root system weight, aboveground height to root
system length, as well as specific root length were determined. It was found that the growth variables of plants were positively influenced by organic fertilizer. The aboveground weight to root system weight ratios of pea ranged from 4.80 to 6.29 and was higher than vetch. Aboveground height to root system length ratio in pea ranged from 6.95 to 7.93, and in vetch from 5.30 to 7.39. The use of organic fertilizer at the dose of 1.2 L/t and treatment during vegetation resulted in better performance of root system and specific root length was 78.6 for pea and 84.3 for vetch.
Accolo - Turn your company into a hiring machine - 3-22-12 - John YoungerJohn Younger
Accolo - Turn your company into a hiring machine - 3-22-12 - This is a presentation given by John Younger, President, CEO and Founder of Accolo at the Marin Business Forum on 3-22-12
Journal of The Earth Science and Climate Change is a peer reviewed academic journal that cater to the needs of Earth Scientists, farmers, extensive agents, researchers and students. This Open access journal publishes high quality articles following rigorous and standard review procedure.
Numerical simulation of biodiversity: comparison of changing initial conditio...IJAEMSJORNAL
This study examined the effect of varying the initial value of industrialization for a fixed length of growing season on the prediction of biodiversity loss. We have found that when the initial value of industrialization is 0.1 under a shorter length of growing season, a relative low due of biodiversity loss can be maintained. The biodiversity loss value can be further lowered by maintaining the same length of growing season but with a reduced initial value of industrialization to 0.01 or 0.02. We would expect this alternative result to provide a further insight into our fight against biodiversity loss which has both human and sustainable development devastating effects.
Germination percentage and growing behavior of Salix tetrasperma (Willow) as ...Innspub Net
Propagation through branch cuttings is one of the best methods to produced tree nursery the yield of the tree produced from a cutting can be higher then a tree produced from seedlings, the conditions provided to them are important factor for getting good results. The aim of this study was to find the best size of cuttings for establishment of nursery and also to compare their performance in open air or in artificial conditions under plastic sheets cuttings of 2 inches, 4 and 6 of Salix tetrasperma were raised in plastic bags of size 3x7 their were three treatments with 25 bags in each and replicated 4 times. The data on sprouting percentage, plant height, root development etc was recorded after every two weeks. The data thus collected was analyzed statically using randomized complete block design. Result showed that cutting of 2 inches has high sprouting percentage and growth behavior as compared to other cuttings. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Food Security Production Challenges in Indonesia as Impact of Global Climate ...Agriculture Journal IJOEAR
— Global food availability, including national as well as local, is highly dependent on the natural resources that will affect crop production. Although there is rain, soil temperatures and conditions have formed a natural system that will support agricultural efforts, but this state is unstable and always changes according to atmospheric conditions in an integrated manner. Human beings on certain boundaries can intervene with the natural resources. Climate (generally a combination of rain, temperature, and sunlight) is the most important growth factor in crop production in the field. Any change in climatic conditions will have far-reaching effects on global food production. Global climate change, excessive land and land exploitation, inaccurate land management, in its time will have an impact on the food production and availability of a region. Knowing well the of nature characteristics, then anticipating the impact that will arise and determine the ways of handling it, is a series of business and activities that must be done to achieve food security. To anticipate climate change and its impacts on crop production, a broad outline can be made by considering the following physical technic aspects: 1) adjusting cropping patterns; 2) increasing the area of forest cover and catchment areas; 3) application of land and crop management technology. Some application of land and crop management technologies include: organic farming, implementation of Surjan system, food diversification, large tree planting, water pond production, etc. The policies that need to be taken as a solution in anticipating the impact of global climate change are 1) the preparation and stipulation of special food agriculture scenarios, including the zoning of production potential and zonation of climate risk (drought, flood, landslide, etc.) with the updating of data every year; 2) reducing the conversion of agricultural land (food); 3) incentives for farmers; 4) changing the consumption pattern of the people, from the consumption of rice to alternative staple foods; 5) subsidies and protection of food farming; 6) climate monitoring and prediction (early rainy season, long growing period, and potential water availability; 7) Revitalization of watershed (DAS) functions; 8) Multiply the artificial water absorption area.
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/
Effect of minimum tillage and Mulching on nutrient Transformation in rice bas...P.K. Mani
Paper presented at PAU, LUdhiana, 2012 describing nutrient transformation in rice based cropping system following zero tillage vs conventional tillage.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Aboveground to root biomass ratios in pea and vetch after treatment with orga...GJESM Publication
Some growth parameters of pea (cv. Pleven 4) and vetch (cv. Obrazets 666) after treatment with organic fertilizer were studied in a field trial carried out at the Institute of Forage Crops, Pleven, Bulgaria. Humustim as
organic fertilizer was applied through presowing treatment of seeds, treatment during vegetation and combination
between both, at different doses. Ratios of aboveground weight to root system weight, aboveground height to root
system length, as well as specific root length were determined. It was found that the growth variables of plants were positively influenced by organic fertilizer. The aboveground weight to root system weight ratios of pea ranged from 4.80 to 6.29 and was higher than vetch. Aboveground height to root system length ratio in pea ranged from 6.95 to 7.93, and in vetch from 5.30 to 7.39. The use of organic fertilizer at the dose of 1.2 L/t and treatment during vegetation resulted in better performance of root system and specific root length was 78.6 for pea and 84.3 for vetch.
Accolo - Turn your company into a hiring machine - 3-22-12 - John YoungerJohn Younger
Accolo - Turn your company into a hiring machine - 3-22-12 - This is a presentation given by John Younger, President, CEO and Founder of Accolo at the Marin Business Forum on 3-22-12
Тарнавский Виктор Вадимович
Руководитель отдела аналитики, ИИС "Металлоснабжение и сбыт"
Тема доклада: «Макроэкономический анализ текущей ситуации в экономике и металлургии России»
Q: Can I simply hire one rockstar data scientist to cover all this kind of work?
A: No, interdisciplinary work requires teams
A: Hire leads who can speak the lingo of each required discipline
A: Hire individual contributors who cover 2+ roles, when possible
Statistical Thinking – Solve the Whole Problem
BONUS: Meta Organization – Integration with Adjacent Teams
Co-authors Allen Day @allenday and Paco Nathan @pacoid
The science driving genomic analyses is rapidly changing, but the operational problems of processing data from DNA sequencers quickly and reliably are not new.
I present an analysis of the parallels in the fundamental limiting components of the '90s internet boom and the DNA sequencing boom that is currently underway, and illustrate how Hadoop, a proven application architecture used widely in BigData and commercial internet applications can be reused in the genomics sector.
Effect of early age thermal challenge on growth performance, haematological p...Innspub Net
This study aimed to evaluate the effect of thermal stress on haematological profile and carcass yield of guinea fowl (GF). A total of 180 one-day old GF keets were assigned to 3 treatments, having 4 replicates of 15 birds each. The treatments were: control (T1); mild heat stress for 6h/day (T2), and high heat stress for 8h/day (T3). Data were collected on weekly body weights, feed intake and feed conversion ratio of the birds. At 6-weeks old, blood samples were collected from 8 GF for determination of haematological profile. At 14-weeks old, 8 birds were also slaughtered per treatment to evaluate relative organ weights, carcass characteristics and immune response. Results showed that the body weight gain and feed intake of the birds of T1 and T2 were similar and significantly higher than that of T3 at week 1 of age. The FCR of the birds in T1 and T2 were also better at this stage. Lymphocyte counts were higher (p<0.01) in the birds of T2 (95 103/mL) than those of the control (93.33 103/mL) and T3 (93.33 103/mL). The weights of lymphoid organs of T2 and T3 birds were higher (p<0.05) than those of the control group. It was concluded that exposure of keets to heat stress for 8h/day had adverse effects on growth performance at the early age but this effect faded with age. The thermal manipulation in this study didn’t influence the carcass yield but improved the weights of lymphoid organs of indigenous GF, indicating a better thermo-tolerance.
Modeling the solar drying kinetics of gamma irradiation-pretreated oyster mus...Nii Korley Kortei
Oyster mushroom slices (Pleurotus ostreatus) were exposed to ɣ-radiation as a pretreatment and
solar dried to investigate the influence of irradiation on drying kinetics. Processing conditions
included exposure of mushrooms to 0 kGy (control), 0.5 kGy, 1.0 kGy, 1.5 kGy and 2.0 kGy
of ɣ-radiation at a dose rate of 1.7 kGy/h and drying at a mean temperature of 53.2±6.4°C.
Experimental drying data were fitted to 5 thin layer drying models by non-linear regression.
Irradiation was observed to enhance the drying rate of mushroom slices, with higher doses
causing faster moisture removal. Drying characteristics of slices exposed to lower dosages were
best described by Page’s model (R2=0.9878, 0.9967, 0.9925 correspondingly for “control” (0.0
kGy), 0.5 and 1.0 kGy while the Diffusion model best fit the data for those exposed to higher
doses of radiation (R2=0.9938, 0.9890 for 1.5 and 2.0 kGy respectively). Deff ranged from 1.88
to 2.44 x 10-08 and increase from “control”, 0.5 kGy, 1.0 kGy, 1.5 kGy to 2.0 kGy. Irradiation
of mushrooms as a pretreatment for drying increases moisture diffusivity and drying rate with
higher doses having the most effect.
Dynamic Assessment of Air Temperature for Tomato (Lycopersicon Esculentum) Cu...Redmond R. Shamshiri
Net-screen covered greenhouses operating on natural ventilation are used as a sustainable approach for closed-field cultivation of fruits and vegetables and to eliminate insect passage and subsequent production damage. The objective of this work was to develop a real-time assessment framework for evaluating air-temperature inside an insect-proof net-screen greenhouse in tropical lowlands of Malaysia prior to cultivation of tomato. Mathematical description of a growth response model was implemented and used in a computer application. A custom-designed data acquisition system was built for collecting 6 months of air-temperature data, during July to December 2014. For each measured air-temperature (T), an optimality degree, denoted by Opt(T), was calculated with respect to different light conditions (sun, cloud, night) and different growth stages. Interactive three-dimensional plots were generated to demonstrate variations in Opt(T) values due to different hours and days in a growth season. Results showed that, air temperature was never less than 25% optimal for early growth, and 51% for vegetative to mature fruiting growth stages. The average Opt(T) in the entire 6 months was between 65 and 75%. The presented framework allows tomato growers to automatically collect and process raw air temperature data and to simulate growth responses at different growth stages and light conditions. The software database can be used to track and record Opt(T) values from any greenhouses with different structure design, covering materials, cooling system and growing seasons, and to contribute to knowledge-based decision support systems and energy balance models.
Quantifying the relative impact of physical and human factors on the viticult...Agriculture Journal IJOEAR
— This work assesses the relative importance of the terroirs factors: climate, soil and the relation source-sink, on the vegetative development, yield, berry composition and plant sanitary status. The study was carried out between 2011 and 2014 in nine vineyards from six viticultural regions over the coast of Río de la Plata (Uruguay). The cultivar studied was Tannat, vertically trellised and north-south oriented. The year effect refers to climate, which was characterized using solar irradiation and three indices. The soil was characterized using pits and physico-chemical analyses, to determine three textural categories and to define soil depth and water availability. The source-sink relationship referred to four categories of relations between leaf surface and yield per vine. Statistical analyses included a Mixed Model with random effects to determine the relative importance of each factor to the total variability within the dataset. Total yield per vine was explained by the source-sink relationship, the year and their interaction, both linked to the rainfall amount occurred during the maturation period. The synthesis of primary compounds in the berries was more dependent on the year and the interaction of soil and year with the source-sink relationship. Secondary compound concentrations in the berry depended mainly on the source-sink relationship and climate. This study represents a significant advance to the knowledge of grapevine adaptation to the Río de la Plata terroirs, assigning a fundamental role to the vine grower actions. The growers can modulate grapevine balance as a function of the environment.
Soil Tillage Systems Impact on Energy Use Pattern and Economic Profitability ...CrimsonpublishersMCDA
The role of energy management is important and essential in sustainability of production systems. The aims of this study were evaluated the impact of different soil tillage on energy use in wheat agroecosystems. To purpose this research was carried on 2014 to 2016 years in research farm of Razi University in western Iran. The result of this study showed that total energy used in NT, RT, and CT systems was 31.39, 32.85, and 35.16GJha-1. In the other hands, production energy in NT, RT, and CT systems was 200.14, 207.68, and 195.26GJha-1. Accordingly, energy use efficiency (EUE) in NT, RT, and CT systems was 6.38, 6.32, and 5.55. Therefore, amount of EUE of different tillage systems followed the order of NT>RT>CT systems. In this research profitability of NT, RT, and CT systems were 3.23, 2.96, and 2.59. This result showed that more use of machinery and operation due to more use of energy resource can be reduced EUE, Net energy and profitability of agroecosystems.
https://crimsonpublishers.com/mcda/fulltext/MCDA.000569.php
For more open access journals in Crimson Publishers please click on link: https://crimsonpublishers.com
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Genotype by environment interactions and effects on growth and yield of cowpe...Premier Publishers
Cowpea is widely grown in the humid tropics as staple and is largely affected by genotype by environment interaction (GEI). Data obtained from field trials were subjected to genotype (G) by environment (E) interaction (GEI Biplot) analysis and was applied to examine the nature and magnitude of GEI and quantify their effects on cowpea performance in seven experimental trials in a rainforest and derived savanna agroecologies of south-west Nigeria. Results showed that genotype x environment interactions effects were significant on cowpea growth and yield characters. The differential performance of cowpea varieties as early- and late- rainy season crops at both locations were attributable to variability in the soil, weather and biotic factors of the test environments. Determination of winning genotype(s) and yield ranking across environments showed that cowpea varieties depicted differential performance for the test environments and hence the interaction was crossover type. Varieties IT97K-568-18, IT97K-568-18 and Oloyin Brown are high yielding while IT96D-610 and IT98K-205-8 are poor. Oloyin Brown and IT98K-573-2-1 won in Akure 1, 2, 3 and 4 and Ado 1 while IT97K-568-18 won in Ado 2 and Akure 5. IT96D-610 and IT98K-205-8 did not win in any environment. The best performing varieties, Oloyin Brown, IT97K-568-18 and IT98K-573-2-1 combined both high yield and stable performance across test environments and were characterized as ideal genotypes while most unstable variety, IT96D-610, performed poorly in test environments. It is concluded that Ado-Ekiti was best for the late rainy while Akure location was best for early rainy season cropping.
Development of drought tolerant maize cultivars is prerequisite to achieving stable grain yield in
drought–prone ecologies of Nigeria’s Guinea savanna. However, success has been limited mainly due
to lack of maize genotypes that show clear differences in response to well defined moisture deficit
condition. Two sets of drought tolerant (DT) maize germplasm were evaluated under screenhouse and
field conditions between 1999 and 2002. In the screenhouse study, performances of the genotypes
were compared under well-watered condition and moisture deficit imposed at different growth stages.
Under field conditions, the first set comprising 11 accessions along with a check were evaluated for 4
growing seasons while the second set which comprised 3 DT varieties were evaluated along with 2
check varieties using monthly plantings between April and August of 2001 and 2002, respectively. In
the first set, post anthesis moisture deficit significantly reduced grain yield by 25 to 73.5% in the open
pollinated varieties (OPVs) and by 20 to 64% in the hybrids. Grain yield under field conditions ranged
from 2.48 to 3.49, 2.82 to 3.73 and 3.58 to 4.76 tons/ha-1 for 1999, 2000 and 2001 full growing seasons,
respectively, and 2.03 to 2.50 tons/ha-1 for 2000 late growing season. In the second set, pre and post
anthesis moisture deficits reduced grain yield by 77.6 and 95.8%, respectively, of well watered
condition while in the field, grain yields in the genotypes were highest for plantings made in April and
July (1.90 - 2.5 t/ha), lowest for August (0.7 -1.8 t/ha) when moisture deficit coincided with
reproductive phase. Yield stability exhibited under moisture deficit and on the field by 8522-2, Oba
super 2 and AK9943-DMRSR in the first set as well as DT-SR-Y C0 and DT-SR-W C0 in the second set,
indicates their suitability either as cultivars per se or as potential source of DT alleles for
development of DT maize varieties for Nigeria’s savanna ecologies.
The Use of in vitro Gas Production Technique as an Index of the Nutritive Val...IOSRJAVS
: The in vitro gas production technique was used to predict rumen fermentable organic matter, gas production kinetics, organic matter digestibility as well as metabolizable energy were evaluated in green shoot, leaves, fruits flesh and seed cakes of Ziziphus spina-christi tree. A gas production was measured by incubating samples in buffered rumen fluid from cannulated steer for 72 h. Total gas production was recorded at 0,3, 6, 9, 12, 24, 48, and 72 h of incubation periods and kinetics of gas production was described. The chemical analysis of these Ziziphus spina-christi parts, showed that, Leaves contained high protein (14.77±0.23g/kg) and green shoot less protein (8.03±0.15g/kg),however, high ash content was observed in green shoot (10.03±0.07g/kg) compare to other parts. seed cakes has the highest crude fibre content in comparison to other parts (32.46±0.01),while fruits flesh contained the highest ether extract(72.39±0.03).The maximum gas volume was highest for fruits flesh followed by seed cakes, green shoot and leaves after 24hr of incubation. In this study flesh had a significantly higher (P<0.05) gas production from rapid soluble fraction (a) than the other parts, while Ziziphus spina-christi leaves showed the highest gas production from slowly degradable fraction (b) .Organic matter digestibility range was (51.90– 43.79%) and Metabolisable energy was found to be (9.16– 6.74MJ/kgDM) in the flesh and green shoot, respectively. It was concluded that, green shoots, leaves, fruit flesh and seed cake of Ziziphus spina-christi have the potential to be used as protein, energy and mineral supplements for ruminants especially during the dry season
1. Pak. J. Bot., 43(3): 1621-1627, 2011.
IS PHOTOTHERMAL QUOTIENT DETERMINANT FACTOR FOR SPRING WHEAT YIELD?
M. AHMED*1
, FAYYAZ-UL-HASSAN1
, ABDUL RAZZAQ1
, M.N. AKRAM1
,
M. ASLAM2
, S. AHMAD3
AND M. ZIA-UL-HAQ4
1
Department of Agronomy, PMAS Arid Agriculture University Rawalpindi-46300, Pakistan;
2
Ministry of Food and Agriculture Islamabad, Pakistan;
3
Department of Agronomy, Bahauddin Zakariya University, Multan-60800, Pakistan
4
Department of Pharmacognosy, University of Karachi, Karachi-75270, Pakistan,
Abstract
Photothermal Quotient as combined effect of temperature and solar radiation were studied as determinant factor for spring wheat grain
yield. The data obtained at anthesis and maturity for grain m-2
, grain weight and grain yield were examined in experiments involving three wheat
genotypes under five different environmental conditions (E) provided in the form of planting windows (PW’s) during 2008-09 & 2009-10 at
National Agricultural Research Center (NARC), Islamabad. The mean temperature at anthesis (T1) and maturity (T2) was calculated by
averaging all temperature from germination till anthesis and maturity, respectively. Similarly, solar radiation at anthesis (SR1) and maturity
(SR2) was calculated- with the Angstrom formula while Photothermal quotient (PTQ) was calculated at anthesis (PTQ1) and maturity (PTQ2).
The data obtained was subjected to STATISTICA 8 software and scatter plot regression model was developed- at 95% confidence interval with
crop data and climate variables (T1, T2, SR1, SR2, PTQ1 and PTQ2). The b (regression coefficient) recorded were 623.73 (GM vs T1), 0.0037
(GW vs T1), -5.97 (Y vs T1), -0.028 (GW vs T2), -1356.28 (GM vs T2), -57.86 (Y vs T2), 29.53 (GM vs SR1), 0.0005 (GW vs SR1), 3.95 (Y vs
SR1), 19.90 (GM vs SR2), 0.0003 (GW vs SR2), 2.57 (Y vs SR2) 314.20 (GM vs PTQ1), 0.0049 (GW vs PTQ1), 49.88 (Y vs PTQ1), 0.0037
(GW vs PTQ2), 31.87 ( Y vs PTQ2), 237.40 (GM vs PTQ2) while, b for E and PW with yield was -872.51 and -309.75, respectively. Direct
relationship between PTQ and yield parameters confirmed that it determined crop yield and its management for variable environmental
conditions need to be opted by adopting suitable sowing time.
Introduction
Climatic factors like temperature, solar radiation and
rainfall impact on crop yield all over the world. Changes in
climatic factors like rise in temperature and decline in rainfall
were reported in the report of the Intergovernmental Panel on
Climate Change (IPCC, 2007a, b). Low temperature in the
growing season may reduce germination, retard vegetative
growth by inducing metabolic unbalances and can delay or
prevent reproductive devolvement (Mohsen & Yamada, 1991).
You et al., (2009) observed significant reduction in yield due
to rise in temperature and it was concluded that with 1.8o
C rise
in temperature caused 3-10 % reduction in wheat yields. The
impact of climatic variables can be assessed by studying
climatic parameters like temperature, solar ration and
Photothermal Quotient (PTQ) during crop life-cycle and by
developing a quantitative relationship among climatic
variables and crop yield. Li et al., (2010) observed significant
change in yield of wheat due to variation in temperature and
solar radiation. Similarly, 0.6 to 8.9% reduction in wheat yield
per 1o
C rise in temperature has been recorded by Lobell &
Field, (2007). Ormerod et al., (2003) reported that agricultural
production is more complex because of the need to balance
global food security, optimum production, technological
innovation, preservation of environmental functions and
protection of biodiversity. The ecological knowledge achieved
in the present study enables considerable compliance with
most of those objectives.
Development of genotypes resistance to extreme climatic
events needs to be considered as potential option for wide
range of conditions with agronomic managements like sowing
dates (Bedo et al., 2005). Limited availability of climatic
resources has generated marginal environments where wheat
production drops to 70% of optimum yield (Rajaram, 2005).
Photothermal quotient (PTQ) can be defined as the ratio
of total solar radiation in MJ m-2
day-1
to the mean daily
temperature minus a base temperature (4.5o
C for Spring
Wheat). Nalley et al., (2009) identified, PTQ to improve the
explanatory power of statistical regression models on grains
per meter square (GM), grain weight (GW) and yield under
climate change scenario. Similarly, Khichar & Niwas (2007)
concluded direct relationship with PTQ and growth of wheat
under different planting systems. However, Loomis & Amthor
(1996) documented that crop growth and yield were derived
from photosynthesis, therefore dependent on receipt and
capture of solar radiation. Hence studies are needed to
understand and quantify the crop response and its relationship
with varied combination of temperature and solar radiation to
workout suitable planting windows for wheat. This is only
possible if the canopies are tested under varying circumstances
of temperature and radiation. The practical way to record such
reading is to alter the sowing time of the crop within
recommended growing season. The objectives of this study
were to evaluate the effect of mean temperature, total solar
radiation and PTQ at anthesis and maturity stage of wheat crop
during different environments (2008-09 & 2009-10) and
thereafter to develop a regression model for climatic variables
with grain weight, grains per meter square and yield of wheat
crop for wide range of conditions.
Materials and Methods
Experimental site and field conditions: Five different
planting windows (PW’s) were used to provide variable
climatic conditions at anthesis and maturity of wheat for two
environments i.e. 2008-09 & 2009-10. The planting windows
were; PW1 (Sowing on 20-10-2008 & 23-10-2009), PW2
(Sowing on 28-10-2008 & 05-11-2009), PW3 (Sowing on 05-
11-2008 & 19-11-2009), PW4 (Sowing on 19-11-2008 & 27-
11-2009) and PW5 (Sowing on 05-12-2008 & 10-12-2009).
The study was conducted at National Agriculture Research
Center (NARC), Islamabad, Pakistan, located at latitude of 33o
42/
N and longitude of 73o
10/
E. The soil series of study site
was Rajar, with great groups Ustorthents and soil order
Entisol. The experiments were laid out using randomized
complete block design (RCBD), replicated four times in 4.5 x
10 m plot with row spacing of 25 cm. Wheat genotypes
Chakwal-50, Wafaq-2001 and GA-2002 were used in the
study. Sowing was done by hand drill using seed rate of 50 kg
acre-1
. Prior to sowing particular field remained fallow during
summer which was ploughed once with soil inverting
implement and thereafter thrice with tractor mounted
cultivator. Recommended doses of fertilizer Nitrogen and
Phosphorus at the rate of 100 kg ha-1
was added with last
cultivation in the form of Urea and DAP.
*
Corresponding author’s email: shakeel.agronomy@gmail.com
2. M. AHMED ET AL.,1622
Environmental characterization: Data regarding weather
prevailed during the study period was collected from the
weather station located at NARC. The mean temperature at
anthesis (T1) and maturity (T2) was calculated by averaging
all temperature from germination till anthesis and maturity,
respectively. Similarly, solar radiation at anthesis (SR1) and
maturity (SR2) was calculated with the Angstrom formula,
which relates solar radiation to extraterrestrial radiation and
relative sunshine duration:
Rs = as + bs n Ra
where Rs = solar or shortwave radiation [MJ m-2
day-1
], n = actual
duration of sunshine [hour], N= maximum possible duration of
sunshine or daylight hours [hour], n/N = relative sunshine
duration [-], Ra = extraterrestrial radiation [MJ m-2
day-1
], as =
regression constant, as + bs = fraction of extraterrestrial radiation
reaching the earth on clear days (n = N). The default values for as
and bs were 0.25 and 0.50. The photothermal quotient was
calculated on daily basis with following formula: If T > 10, PTQ
day-1
= Solar Radiation / (T - 4.5), If T < 4.5, PTQ day-1
= 0; and,
If 4.5 < T < 10, PTQ day-1
= Solar Radiation x [(T – 4.5) / 5.5]
/5.5. Where, T is the daily mean temperature [(max + min) / 2]
and PTQ is expressed as MJ m-2
day-1 o
C-1
(Monasterio et al.,
1994). The following PTQs were generated for individual
genotypes by adding the daily PTQ: PTQ1 at anthesis by adding
daily PTQs from germination to anthesis; PTQ2 at maturity by
adding daily PTQs from germination to anthesis + anthesis to
maturity. All genotypes at maturity were harvested and grain
number per meter square (GM), grain weight (GW) and grain
yield (kg ha-1
) were calculated.
Statistical analysis and procedures: The data obtained was
subjected to STATISTICA 8 (Statsoft, Inc. 2007) software to
develop a regression models among T1, T2, SR1, SR2, PTQ1
and PTQ2 with GM, GW and grain yield (kg ha-1
). Two-
dimensional scatterplots obtained visualized a relation between
two variables X and Y (e.g. T1 and GM). The regression
analysis performed was with confidence interval of 95%.
Results
Relationships between grain number m-2
(GM), grain
weight (GW) and grain yield (kg ha-1
) with T1 (mean
temperature at Anthesis) and T2 (mean temperature at
maturity): The results of scatter plot of GM against T1 (Fig.
1a) showed significant and positive relationship between
anthesis temperature and grain numbers. The maximum
number of GM was recorded between temperatures of 18-20o
C
with R2
(0.89). The regression equation obtained was GM =
5308.99 + 623.73 (T1) with 0.95 confidence interval. The
result clearly indicated a strong relationship of anthesis
temperature with grain number which may be further
correlated with grain yield. Thus, at anthesis if available
temperature to crop is optimum it leads to good seed setting.
Similarly, response of grain weight with T1 showed the
maximum grain weight obtained at 17o
C with regression
equation (GW = 0.34 + 0.0037 (T1). The relationship between
anthesis mean temperature and grain weight depicted a
positive association with R2
of 0.78 but up to optimum level
(Fig. 1b). Further increase in temperature after optimum level
may lead to shriveled grains and produce lesser grain weight.
However, yield association with temperature at anthesis
showed yield reduction with increase in temperature (Fig. 1c).
Similarly temperature rise may have caused yield stagnation.
The regression equation obtained for yield in relation with T1
was Y = 3284.7553-5.9702 (T1). The relationship of mean
temperature from germination till maturity (T2) with GM, GW
and grain yield revealed decline in GM, GW and yield with
increase in temperature (Fig. 1d-f). The adverse effect of high
temperature on yields could partially be modified by
avoidance strategy including earlier sowing. The biological
clock acceleration because of the increased temperature
brought forward developmental stages and reduced the
growing period between emergence and maturity. The
regression equations obtained at 95% confidence interval for
GM, GW and grain yield was GM = 47367.06-1356.28 (T2),
GW = 1.05-0.02 (T2) and Y = 4542.37-57.86 (T2),
respectively. The regression model showed a negative trend
with unit increase in temperature from emergence to maturity.
Relationships between grain number per square meter
(GM), Grain weight (GW) and Grain yield (kg ha-1
) with
SR1 (total solar radiation at Anthesis) and SR2 (total solar
radiation at maturity): Solar radiation might affect crop
growth through a variety of direct and indirect mechanisms.
Similarly, solar radiation activates the photosystem by which
light reaction of photosynthesis started and electrons generated
by photolysis of water moves to produce energy carriers (e.g.
NADPH & ATP). The scatterplot regression model showed a
positive relationship between GM, GW and grain yield with
SR1 and SR2 (Fig. 2). The regression model obtained for GM,
GW and yield with SR1 was GM = -19542.51 + 29.53 (SR1),
GW = -0.15+0.0005 (SR1), Y = -1516.47+3.9549 (SR1),
respectively. The result showed that SR1 linked positively
with yield which may be because of good source-sink activity.
Likewise, the responses of crop yield parameters (GM, GW
and yield) with SR2 were associated positively. The result
indicated that with increase in solar radiation from emergence
till maturity brought a significant yield impact. The regression
model equation showed a direct relationship with SR2 and
GM, GW and yield (GM = -21272.63 + 19.90(SR2), GW = -
0.1551+0.0003(SR2) and Y = -1575.8369+2.57 (SR2)).
Relationships between grain number per square meter
(GM), grain weight (GW) and grain yield (kg ha-1
) with
PTQ1 (Photothermal quotient at anthesis) and PTQ2
(Photothermal quotient at maturity): Photothermal Quotient
portrayed the combined effect of solar radiation and temperature
on crop yield components. Grain numbers per meter square
(GM), grain weight (GW) and grain yield (kg ha-1
) were
positively related to PTQ1 with R2
of 0.88, 0.66 and 0.59. The
regression equation indicated that with unit change in PTQ1,
GM increased at the rate of 314.20 while GW showed increase
of 0.0049. Similarly, grain yield associated directly with the
impact of 49.88 per unit of PTQ1. The regression model
obtained between PTQ1 and yield components clearly indicated
that PTQ1 determined the GM, GW and yield positively if all
other resources remained available at optima. The regression
model obtained was GM = -28518.88 + 314.20 (PTQ1), KW = -
0.287 + 0.0049 (PTQ1) and Y = -3814.91 + 49.88 (PTQ1) at
0.95 confidence interval (Fig. 3a-c). Similarly, PTQ from
emergence to maturity determined the overall impact of climate
variables on crop growth. Therefore, PTQ available to crop for
late planting windows was recorded minimum. Hence, yield
GM, GW and yield recorded for late planting windows
remained significantly lower. The scatterplot obtained for PTQ2
with grain numbers per meter square (GM), grain weight (GW)
and grain yield (kg ha-1
) indicated a positive association (Fig.
3d-f). The regression models obtained between PTQ2 and GM,
GW and yield depicted that PTQ is key determinant factor
which affected yield significantly (GM = -27382.86 + 237.40
(PTQ2), GW = -0.27 + 0.0037 (PTQ2) and Y = -2582.43 +
31.87 (PTQ2)).
N
3. IS PHOTOTHERMAL QUOTIENT DETERMINANT FACTOR FOR SPRING WHEAT YIELD? 1623
Fig. 1. Scatter plot of (a & e) Grains per meter square (GM), (b & d) Grain weight (GW) & (c &f) Yield (kg ha-1
) against mean temperature (o
C)
at anthesis (T1) & at maturity (T2).
4. M. AHMED ET AL.,1624
Fig. 2. Scatter plot of (a & d) Grains per meter square (GM), (b & e) Grain weight (GW) & (c & f) Yield (kg ha-1
) against total solar radiation
(MJ m–2
) at anthesis (SR1) & at maturity (SR2).
5. IS PHOTOTHERMAL QUOTIENT DETERMINANT FACTOR FOR SPRING WHEAT YIELD? 1625
Fig. 3. Scatter plot of (a & e) Grains per meter square (GM), (b & d) Grain weight (GW) & (c &f) Yield (kg ha-1
) against Photothermal Quotient
(MJ m-2
day-1 o
C-1
) at anthesis (PTQ1) & at maturity (PTQ2).
6. M. AHMED ET AL.,1626
Discussion
The significant negative trend of GM and GW with
increased temperature revealed that crop growth and
development was affected adversely with rise in temperature.
Gate, (2007) concluded that maximum temperatures above
25o
C significantly reduced grain weight while Kalra et al.,
(2008) confirmed that wheat yields have fallen by 0.2–0.5 t
ha−1
per degree Celsius rise in temperature. Similarly, decrease
in grain m-2
may be due to high temperature near heading. This
phenomenon is similar to findings of Dawson & Wardlow
(1989). They reported that high temperature during the pre-
heading stage might have minimized pollen viability, resulting
in less number of kernels per spike. The reduction in grain
weight due to rise in temperature may be because of inefficient
activity of sink (Fig. 1). Lin et al., (1997) concluded that floral
sterility may limit sink due to increased temperature. In
present study yield obtained was maximum at optimum and
decreased due to rise in temperature. The temperature rise
during crop growth cycle might result in seed abortion and
reduced grain yield (IPCC, 2001a). Increased temperature
from germination to maturity may affect grain developmental
period of wheat crop. The rising temperature would shorten
the period of grain filling in wheat (Wheeler et al., 1996).
Solar radiation is an important environmental factor of
crop growth which brings positive changes in the crop growth
by altering leaf architecture and light partioning. The result
showed that with increase in solar radiation GM, GW and
yield increased significantly. Richards, (2006) found a
significant similar effect of seasonal variations of solar
radiation on yield. This significant responsive trend of crop
toward solar radiation may be due to modification in duration
of photosynthesis. Sowing time may be used to bring
variability in solar radiation which ultimately effects on the
duration of crop growth due to differential partioning of light.
Since if crop is exposed to favorable environmental conditions
for longer period of time it may bring good seed setting and
yield. However, growth and development would become
negative because of weaker solar radiation due to cloud cover.
Therefore, result clearly indicated that variations in
environmental factors may lead to change in crop yield, thus
conclusion of present investigation is in line with Rodriguez &
Sadras (2007).
GM was the determinant factor for variation in grain yield
(Slafer et al., 1994; Egli, 1998) which was significantly
affected due to Photothermal Quotient at anthesis and maturity
(Fig. 3). Hence, results of present study are similar to above
conclusion. Significant positive association was recorded
between grain m-2
with PTQ1 and PTQ2 (R2
= 0.97 and R2
=
0.90). The maximum value of PTQ (217.66) recorded for early
sowing may be due to favorable environmental conditions
throughout crop life cycle. Thus, these results correspond with
the results of Monasterio et al., (1994). Similarly, kernal
weight (KW) and photothermal quotient accounted a linear
positive trend. The highest kernal weight was recorded when
maximum PTQ avialble from emergence to maturity. Similar
findings were reported by Khichar & Niwas (2007) who
concluded that photothermal quotient effects on kernel weight
decisively provided all other resources were available at
optimum level. Yield was strongly linked with PTQ1 and
PTQ2 (Fig. 3). The highest yield was obtained with maximum
Photothermal quotient which dropped significantly due to
decrease in PTQ. This declining trend may be because of
unavailability of optimum environmental conditions. Similar
findings were reported by Abbate et al., (1997). The
association of Photothermal quotient at maturity with GW and
grain yield followed a positive trend. As explained by Giulioni
et al., (1997), high temperature has been suggested a factor
that accelerates the ending of crop cycle. The outcomes
generated in this study clearly indicated a strong association
between Photothermal Quotient and GM, GW and yield
(Dumoulin et al., 1994). However, work like association of
Photothermal quotient models with grain developments and
yield components needs to be documented in order to build a
comprehensive model between Photothermal quotient and
crop growth and development. Since, PTQ elaborated the
combined effect of temperature and solar radiation on crop
yield it may be considered as limiting factor which may
control overall crop growth.
Conclusion
Experimental results clearly indicated that yield is directly
proportional to the PTQ provided rests of all the resources are
available optimally. Since, PTQ fulfilled the crop light,
temperature and solar radiation requirement so it is the main
limiting factor which determined the crop adaptation under
specific environments. Management such as Planting
Windows option may be a tactical measure for the adjustment
of PTQ’s according to varying climate of experimental site.
Adaptability of Wheat genotype based upon its relationship
with PTQ knowledge for a particular climate zone can be
recommended to minimize losses in the yield due to extreme
climatic events.
Acknowledgement
The authors express special thanks to HEC (Higher
Education Commission, Islamabad, Pakistan) for the financial
support to complete this research work.
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(Received for publication 6 July 20)