Genetic analysis for various yield components and gluten content in bread wheat (Triticum aestivum L.)

Genetic analysis was carried out in 55 genotypes (10 parents and 45 F1s) through diallel mating design excluding reciprocals in bread wheat (Triticum aestivum L.). Analysis of variance showed wide range of variability among the breeding material for all the traits under study. The highest value of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were recorded for grain yield (PCV= 9.07 and GCV= 8.08). Highest heritability with genetic advance was recorded for grain yield (h2=10.60 and GA=14.84), therefore selection will be effective based on grain yield for further study. Grains per spike (gr = 0.77 and pr = 0.67) and spikelets per spike (gr= 0.63 and pr = 0.52) were found significantly correlated (at <1 % level of significance) with grain yield whereas gluten content showed nonsignificant but positive correlation with grain yield at both genotypic as well as phenotypic level. Similarly, path coefficient analysis estimates for gluten content (g= 0.08 and p= 0.03) and grains per spike (g=0.36 and p=0.23) showed high positive direct effects on grain yield therefore these traits may be used as an index for selection to high yield in bread wheat genotypes

Estimates of genetic components and regression analysis for grain yield and various morphological traits in bread wheat (Triticum aestivum L.)

The present study was conducted to estimate the gentic components and regression analysis for grain yield and various morphological traits in bread wheat involving 10 parents and their 45 F1s (half diallel) during 2012- 13 and 2013-14. Significant additive (D) and dominance (H1) variance for the traits indicated that expression of these traits is control by both additive and dominance gene action. Average degree of dominance (H1/D)1/2 were more than unity for the traits (peduncle length, flag leaf area, productive tillers, biological yield, grain yield, harvest index) indicating the preponderance of over dominance gene action. The estimates of h2 were positive and significant for days to ear emergence, peduncle length, productive tillers, biological yield and grain yield indicated dominance of genetic components in F1s. Positive and significant values of F were estimated for days to ear emergence, days to 50% flowering, spike length, flag leaf area and grain yield in F1s indicating the preponderance of dominance and positive genes in the parents involved. The theoretical value (0.25) of (H2/4H1) for all the traits indicated asymmetrical distribution of positive and negative genes. The proportion of dominant and recessive alleles indicated presence of dominant alleles in the parents. The traits showing more than 30% narrow sanse heritability could be rewarding for further improvement in grain yield in bread wheat. Regression analysis indicated that the traits (days to ear emergence, days to 50% flowering, peduncle length, flag leaf area, productive tillers, harvest index, biological yield and grain yield) control by over dominance type of gene action. The parent RAJ 4246 contained maximum dominant genes for days to ear emergence and days to 50% flowering; HD 2733 for spike length and flag leaf area and HD 2824 for productive tillers, biological yield and grain yield used as donors in multiple traits breeding programme to develop high yielding wheat genotypes

Identification of heterotic cross combinations for various agromorphological and some quality traits in bread wheat (Triticum aestivum L.)

A study was conducted to identify the best heterotic cross for various agromorphological and some quality traits involving 10 parents and their 45 F1s excluding reciprocals during 2012-13 and 2013-14. The higher magnitude of heterosis for all the agromorphological and quality traits was not expressed in a single cross combination. It varied from cross to cross due to diverse genetic background of their parents. The highest heterobeltiosis (35.68%, 11.11%, 11.44%), average heterosis (38.97%, 9.13%, 10.26%) and standard heterosis (31.09%, 7.84%, 10.41%) for grain yield, spikelets per spike and grains per spike respectively, was showed by HD 3095 x RAJ 4246 and this cross also showed highly significant (at <1% level of significant) heterosis for biological yield, flag leaf area, spike length and productive tillers. Whereas PBW 435 x RAJ 4246 were common for gluten content (8.52% and 7.72%), grain yield (33.11% and 33.64%), productive tillers (16.15% and 13.53%) and biological yield (36.27% and 21.98%) which showed superior average heterosis and heterobeltiosis respectively, therefore, these crosses may be exploit-ed in a national hybrid wheat breeding programme may offer genetic improvement in breeding for higher grain yield, agromorphological and quality traits in bread wheat. The presence of high heterosis for yield contributing compo-nents is not only for developing hybrids through exploitation of heterosis but also helps to produce transgressive segregants for developing of superior homozygous lines