Genetic behavior for kernal yield and its physio-agronomic attributes in maize at normal and high temperature regimes

Cell membrane thermostability and seedling plant biomass were used to select suitable parents for hybridization against high temperature stress from 77 inbred lines. Six diverse parents with respect to high temperature stress tolerance viz; two high temperature tolerant (935006, R2205-5-4), two moderately tolerant (F-165-2-4, F101-7-2-6) and two high temperature susceptible maize inbred lines (F113-1-1-1 and R2304-2) were selected and crossed in a full diallel fashion to evaluate inheritance pattern of physio-agronomic traits. Data regarding physiological traits viz., osmotic potential, transpiration rate, growing degree days (GDDs) to 50% tasseling and agronomic traits viz; number of kernels plant-1 and kernels yield plant-1recorded were at normal and high temperature stress regimes. Analysis of variance revealed highly significant variation (P < 0.01) for all the traits studied except osmotic potential at normal temperature regime which was significant at P < 0.05. Transpiration rate, growing degree days to 50% tasseling, number of kernels plant-1 and kernel yield plant-1 showed partial fitness of the data either at normal or higher temperature regime while osmotic potential showed partial fitness of the data by regression analysis in both temperature regimes. Genetic components of variance and Wr/Vr graph for traits studied depicted preponderance of over dominant gene action except osmotic potential at normal temperature regime which reflected additive gene control at normal temperature regime. High temperature stress modified gene expression in most of polygenic traits

Inheritance pattern of yield attributes in spring wheat at grain filling stage under different temperature regimes

Abstract One hundred spring wheat accessions were assessed for heat tolerance under plastic sheet tunnel resulting in seven parents with diverse heat tolerance. Tolerant and susceptible genotypes were graded on the bases of their relative cell injury percentages and relative values for different yield components. The analysis of variance for relative cell injury % revealed highly significant differences among the genotypes with a range from 28 to 98 %. These 7 parents were crossed in a full diallel system to evaluate the inheritance pattern of some spike related yield attributes (spike length, spikelets per spike, spike density, spike weight, grains per spike and grain yield per plant) under different temperature regimes at grain filling stage. Preliminary ANOVA revealed significant genotypic variation (P&lt;0.01) for all the traits studied under both environments. Spike length, spikelets per spike and spike density revealed partial fitness of data for additive dominance model under normal conditions while other traits like spike weight, grains per spike and grain yield per plant showed full adequacy. Under heat stress all traits showed partial adequacy except for grains per spike which showed full adequacy. Formal ANOVA displayed significant effects for both additive and dominance effects in most characters under both regimes. Grain yield per plant showed significancy for only &apos;a&apos; item under normal conditions and both &apos;a&apos; and &apos;b&apos; under high temperature regime. The additive component of variance (D) was significant and more than dominance variance H 1 and H 2 for spike length, spike density and grain yield per plant under both temperature regimes showing preponderance of additive effects. Grains per spike showed prevalence of dominant gene action under both conditions. Spikelets per spike and spike weight showed dominance effects under normal conditions and additive ones under heat stress. Estimates of narrow sense heritability were moderate to high in almost all the traits except for spikelets per spike under normal conditions in which it was low. Predominance of additive genetic effects in majority of traits under heat stress suggested early generation selection through pedigree method while presence of non-additive effects may respond to heterosis breeding. Keywords: Spring wheat, Additive-dominance model, Inheritance pattern, Heat tolerance. Abbreviations: RCI%= Relative cell injury percentage, a = additive, b= over all dominance effects, c= maternal effects, and d= reciprocal affects, b 1 = directional dominance effects, b 2 = effects due to parents contributing varying degree of dominant alleles, b 3 = specific gene interaction, D= estimate of additive effects, H 1 and H 2 = variation due to dominance effects of genes, F= estimate of the relative frequency of dominant to recessive alleles in the parental lines. F= positive when-ever the dominant alleles are more frequent than the recessive alleles, h 2 = direction of dominance, (H 1 /D) 0.5 =mean degree of dominance, H 2 /4H 1 = proportion of genes with positive and negative effects in the parents, [(4DH1) 0.5 +F]/[(4DH1) 0.5 -F]= proportion of dominant and recessive genes in the parents

Genetic variability and trait association in chickpea (Cicer arietinum L.) genotypes at seedling stage

Eighty elite lines including ten standard varieties of chickpea were evaluated for various seedling parameters. Positive andsignificant genotypic and phenotypic correlations were found for different parameters like seedling length, root length,root/shoot ratio, seedling biomass, leaf length, leaf width and leaf area while root length was positively and significantlycorrelated with other parameters. Root/shoot ratio was positively and significantly correlated with all parameters. Seedlingbiomass had positive and significant genotypic and phenotypic correlations with all the parameters. Leaf length, leaf widthand leaf area also had positive and significant correlation among each other and with other parameters. The estimates of theheritability were high for seedling length, root length, moderate for the root/shoot ratio, seedling biomass and primary leafarea and slightly low for the primary leaf length and leaf width. Higher estimates of heritability and positive correlationcoefficients for seedling length, root length, seedling biomass, leaf length, leaf width and leaf area suggest that selection ofelite genotypes at seedling level might be effective for further breeding programme

Effect of Pickings on Germination Percentage and Fiber Quality Traits in Gossypium Hirsutum L

The present investigations were designed to determine the impact of picking dates on seed germination, 100 seed weight and various fiber parameters. Two genotypes FH-113 and FH-114 were evaluated under early and normal sowing. Nine and six pickings were taken under early and normal conditions, respectively. The results revealed significant variation in both the years for fiber traits but for seed germination, the results were non-significant and for seed weight remained significant under both sowing times, respectively. For picking time the estimates were significant under both sowing times thus exhibiting the major role of picking time in this experiment. For germination percentage, the results were variable for both the genotypes. For genotype FH-113, germination remained above 60% during 1st pick and for 5th, 6th, and 7th pick, the germination rates were higher and nearing almost 70%. For 2nd genotype, the germination remained below 50% from pick-1 to pick-4 and above 50% in pick 5 and 8 but for all other pickings the values remained in the range 45–50%. Under normal sowing both genotypes exhibited germination percentage near 60% at 1st pick but for 2nd and 3rd pick, the germination rate remained between 45% and 50%. Regarding correlation studies among the studied traits germination % had positive and highly significant correlation with 100 seed weight under both sowing times. Fiber fineness and strength had strong and highly significant correlation with fiber maturity under both conditions. The results from this study revealed that pickings during favorable conditions produce better quality and germination

Estudos de vigor híbrido para diferentes produtividades do trigo sob condições normais e de estresse por calor

Terminal heat stress is among one of the major constraints in wheat productivity in many countries of the world including Pakistan. To combat this natural calamity,one hundred spring wheat genotypes were assessed for heat stress tolerance under plastic sheet tunnel resulting in seven parents with varied heat stress tolerance. The seven parents including tolerant, moderately tolerant and susceptible but high yielders were later hybridized in a 7×7 diallel fashion. Analysis of variance revealed significant differences for all the studied traits.The heterosis and heterobeltiosis estimates revealed that thereisdesirable hybrid vigor in the current studies for all the traits evaluated.For grain yield maximum heterosis of 28.70% under normal and 27.02% under heat stress conditions were observed. Regarding heterobeltiosis it remained at 15.58% under normal and 13.62% under heat stress conditions. Similarly desirable negative results were obtained for relative cell injury%, days to heading and maturity and positive significant heterosis and heterobeltiosis was obtained for flag leaf area, biomass per plantand harvest index%. The cross combinations like Inqilab-91×Shalimar-88, Shalimar-88 × Maya/Pavon, Chenab-2000 × Punjab-85, Maya/Pavon × Chenab-2000, Shalimar-88 × Uqab-2000 and Uqab-2000 × Maya/Pavonhave shown good hybrid vigor in terms of various traits studied. Suggestively, they may be further exploited following pedigree or bulk method to develop heat tolerant wheat varieties because of their ability to perform well under normal and even diverse environments.Estresse por calor está entre um dos maiores problemas quanto à produtividadede trigo em muitos países do mundo, incluindo o Paquistão. Para combater esta calamidade natural, cem genótipos de trigo de primavera foram avaliados quanto à tolerância ao estresse térmico sob túnel plástico, resultando em sete pares com tolerância variada a esse estresse. Os sete pares incluindo tolerantes, moderadamente tolerantes e suscetíveis, com exceção do mais elevado foramhibridizados em um esquema7 × 7, emformadialélica.A análise de variância reveloudiferenças significativas paratodas as características estudadas. As estimativasde heterosee heterobeltioserevelaram que há desejávelvigor híbrido,nos estudosatuais, paratodas ascaracterísticas avaliadas.Para a produção de grãoshouve heterosemáxima de28,70%sob condiçõesnormais e27,02%sob condições de estresse térmico. Quanto àheterobeltiose,manteve-se em15,58%normais e13,62%sob condições de estressetérmico.Da mesma forma,desejáveis resultados negativosforam obtidos para% em relação à lesão celular, aos dias para crescimento e maturidade e positivaheteroseeheterobeltioseforam obtidaspara a áreada folha, a biomassa por planta eíndice de colheita%. Ascombinações híbridascomoInqilab-91 ×Shalimar-88, Shalimar-88 ×Maya/Pavon, Chenab-2000 ×Punjab-85, Maya /Pavon×Chenab-2000, Shalimar-88 ×Uqab-2000 e Uqab-2000 ×Maya/Pavontêm mostradovigor híbridobom em termos devárias característicasestudadas.Sugestivamente, eles podem ser mais explorados,seguindométodo genealógicoou a granelpara desenvolvervariedades de trigotolerantesao calordadasuahabilidade de desenvolver-se bemem condições normaise até mesmo emdiversos ambientes

Estudos de vigor híbrido para diferentes produtividades do trigo sob condições normais e de estresse por calor

Terminal heat stress is among one of the major constraints in wheat productivity in many countriesof the world including Pakistan. To combat this natural calamity,one hundred spring wheatgenotypes were assessed for heat stress tolerance under plastic sheet tunnel resulting in sevenparents with varied heat stress tolerance. The seven parents including tolerant, moderately tolerantand susceptible but high yielders were later hybridized in a 7×7 diallel fashion. Analysis of variancerevealed significant differences for all the studied traits.The heterosis and heterobeltiosis estimatesrevealed that thereisdesirable hybrid vigor in the current studies for all the traits evaluated.For grainyield maximum heterosis of 28.70% under normal and 27.02% under heat stress conditions wereobserved. Regarding heterobeltiosis it remained at 15.58% under normal and 13.62% under heatstress conditions. Similarly desirable negative results were obtained for relative cell injury%, days toheading and maturity and positive significant heterosis and heterobeltiosis was obtained for flagleaf area, biomass per plantand harvest index%. The cross combinations like Inqilab-91×Shalimar-88,Shalimar-88 × Maya/Pavon, Chenab-2000 × Punjab-85, Maya/Pavon × Chenab-2000, Shalimar-88 ×Uqab-2000 and Uqab-2000 × Maya/Pavonhave shown good hybrid vigor in terms of various traitsstudied. Suggestively, they may be further exploited following pedigree or bulk method to developheat tolerant wheat varieties because of their ability to perform well under normal and even diverseenvironments.Estresse por calor está entre um dos maiores problemas quanto à produtividadede trigo em muitospaíses do mundo, incluindo o Paquistão. Para combater esta calamidade natural, cem genótiposde trigo de primavera foram avaliados quanto à tolerância ao estresse térmico sob túnel plástico,resultando em sete pares com tolerância variada a esse estresse. Os sete pares incluindo tolerantes,moderadamente tolerantes e suscetíveis, com exceção do mais elevado foramhibridizados em umesquema7 × 7, emformadialélica.A análise de variância reveloudiferenças significativas paratodasas características estudadas. As estimativasde heterosee heterobeltioserevelaram que hádesejávelvigor híbrido,nos estudosatuais, paratodas ascaracterísticas avaliadas.Para a produçãode grãoshouve heterosemáxima de28,70%sob condiçõesnormais e27,02%sob condições deestresse térmico. Quanto àheterobeltiose,manteve-se em15,58%normais e13,62%sob condições deestressetérmico.Da mesma forma,desejáveis resultados negativosforam obtidos para% em relaçãoà lesão celular, aos dias para crescimento e maturidade e positivaheteroseeheterobeltioseforamobtidaspara a áreada folha, a biomassa por planta eíndice de colheita%. AscombinaçõeshíbridascomoInqilab-91 ×Shalimar-88, Shalimar-88 ×Maya/Pavon, Chenab-2000 ×Punjab-85, Maya/Pavon×Chenab-2000, Shalimar-88 ×Uqab-2000 e Uqab-2000 ×Maya/Pavontêm mostradovigorhíbridobom em termos devárias característicasestudadas.Sugestivamente, eles podem sermais explorados,seguindométodo genealógicoou a granelpara desenvolvervariedades detrigotolerantesao calordadasuahabilidade de desenvolver-se bemem condições normaise atémesmo emdiversos ambientes. Hybrid vigor studies for different yield contributing traits inwheat under normal and heat stress conditionsAbstractTerminal heat stress is among one of the major constraints in wheat productivity in many countriesof the world including Pakistan. To combat this natural calamity,one hundred spring wheatgenotypes were assessed for heat stress tolerance under plastic sheet tunnel resulting in sevenparents with varied heat stress tolerance. The seven parents including tolerant, moderately tolerantand susceptible but high yielders were later hybridized in a 7×7 diallel fashion. Analysis of variancerevealed significant differences for all the studied traits.The heterosis and heterobeltiosis estimatesrevealed that thereisdesirable hybrid vigor in the current studies for all the traits evaluated.For grainyield maximum heterosis of 28.70% under normal and 27.02% under heat stress conditions wereobserved. Regarding heterobeltiosis it remained at 15.58% under normal and 13.62% under heatstress conditions. Similarly desirable negative results were obtained for relative cell injury%, days toheading and maturity and positive significant heterosis and heterobeltiosis was obtained for flagleaf area, biomass per plantand harvest index%. The cross combinations like Inqilab-91×Shalimar-88,Shalimar-88 × Maya/Pavon, Chenab-2000 × Punjab-85, Maya/Pavon × Chenab-2000, Shalimar-88 ×Uqab-2000 and Uqab-2000 × Maya/Pavonhave shown good hybrid vigor in terms of various traitsstudied. Suggestively, they may be further exploited following pedigree or bulk method to developheat tolerant wheat varieties because of their ability to perform well under normal and even diverseenvironments

GENETIC ANALYSIS OF RELATIVE CELL INJURY PERCENTAGE AND SOME YIELD CONTRIBUTING TRAITS IN WHEAT UNDER NORMAL AND HEAT STRESS CONDITIONS

Several wheat genotypes were screened against heat stress. Seven wheat ( Triticum aestivum L.) cultivars obtained after screening against heat classified as tolerant, moderately tolerant, and susceptible to heat stress, were mated in a complete diallel mating system to study the inheritance pattern of relative cell injury percentage (cell injury %) and some yield contributing parameters under normal and heat stress conditions. Significant genotypic differences were found (P < 0.01) for all the studied traits under both regimes. The scaling test disclosed partial adequacy for traits such as days to heading and days to maturity, but for flag leaf area and relative cell injury %, it showed full sufficiency under both environments. The model for grain yield per plant and biomass per plant were fully adequate under normal conditions, but partially adequate under stress. The harvest index showed partial adequacy under normal conditions, but was fully adequate under stress. The additive component of genotypic variation (D) was significant for all studied traits and more significant than the H1 and H2 dominance components. Values of the gene proportion with positive and negative effects in the parents (H2/4H1) demonstrated an unequal distribution of dominant genes in the parents for almost all the traits except for flag leaf area, grain yield per plant, and harvest index which showed an equal distribution of dominant genes under stress conditions. High heritability estimates were found for days to heading, days to maturity, flag leaf area, grain yield, and relative cell injury percentage under both regimes. Moderately high estimates were found for biomass per plant and harvest index

Inheritance pattern of earliness in cotton (gossypium hirsutum L.)

Fifty one genotypes of Gossypium hirsutum L. were evaluated for variation based on earliness characteristics and seed cotton yield. Seven divergent genotypes including four early and three late maturing genotypes were crossed in a full diallel mating system. Preliminary ANOVA showed significant differences for all the traits.. Additive-dominance model was employed for the interpretation of inheritance pattern controlling earliness and seed cotton yield. The scaling tests fully met the pre-requisites of additive-dominance model and all the traits in F 1 generation showed complete adequacy. The data for seed cotton yield in F 1 and days take to 1 st boll opening in F 2 generation were partially adequate for additive-dominance model and for boll maturation period was inadequate in F 2 generation. Additive component (D) and dominance components (H 1&H 2) were found significant for all the traits thus confirming the contribution of both additive and non-additive effects in both generations except for days to 1 st flower in F 2 generation where the dominance components were non-significant. Formal ANOVA results revealed the contribution of both additive \u27a\u27 and non additive effects \u27b\u27 for all the traits in both generations except for the trait nodes for 1 st fruiting branch. Inheritance of incase of nodes to 1 st branch was controlled by partial dominance; earliness index by over dominance; and days taken to 1 st boll opening and seed cotton yield by complete dominance in both generations. In F1 generation, days to 1 st flower was controlled by over dominance while in F 2 it was inherited additively. Boll maturation period was controlled by over dominance. Heritability estimates in both generations remained moderate to high except for days to 1 st flower where it was very low. Hybrid vigour can be exploited in the case of traits controlled by complete dominance and over dominance while in cases additive control pedigree selection might be fruitful for improvement of the crop

Inheritance Pattern of Fiber Related Traits under Normal and Hypoxia Conditions in Cotton (Gossypium Hirsutum L.)

An 8 × 8 diallel crossing system was employed in F1 generation of cotton to study the inheritance pattern of fiber related traits like micronaire, strength and maturity under normal and hypoxia conditions. Analysis of variance revealed significant variation (P < 0.01) for all the traits under both environments. The regression coefficient b deviated significantly from zero but not from unity for all studies traits allowed further analysis of the data. The additive component (D) was significant for all the traits and more than the values of dominance components H1 and H2 in case of fiber strength under both conditions and for fiber uniformity under normal conditions thus showing the preponderance of additive genetic effects. For micronaire non-additive effects were predominant under both environments. Estimates of narrow sense heritability for micronaire were 38.6% under normal and 49.5% for hypoxia, 79 and 80% for fiber strength and for fiber uniformity the estimates were 79% under normal conditions and 63% under hypoxia conditions. Predominance of additive genetic effects, high heritability along with partial dominance for fiber strength under both conditions and for fiber uniformity under normal conditions is indicative of early generation selection but for micronaire under both conditions selection may be practiced in later generations