Determination of Variability for Grain Yield and Quality Traits in Gamma-Ray Irradiated Bread Wheat Populations

The s tudy was carried out in the experimental area of the Field Crops Department, Faculty of Agriculture, NamikKemal University in the growing season of 2011-12. In the s tudy, grain yield and its components and some quality traitssuch as 1000 grain weight, wet gluten content, gluten index, sedimentation value and protein content were inves tigated.The results exhibited significant differences among the tes ted genotypes, for all s tudied characters except spike length,indicating genetic variation among them. The genetic variation was higher for grain yield and its components when comparedwith quality characteris tics. These differences show that the effects of increasing gamma irradiation are not sys tematicallynegative for plant height, while positive for all other characters in comparison with controls. In general, it is unders toodthat the highes t percent changes are achieved in 200 and 250 Gy of gamma radiation doses for yield components, whileare in 300-350 Gy for the quality characteris tics. The values of phenotypic coefficient of variation PCV were slightlyhigher than their corresponding values of GCV for all traits. Moderate es timates of genotypic coefficient of variation GCVwere obtained by grain yield (12.50%), gluten content (11.20%) and grain weight per spike (10.20%), respectively. Lowes timates of GCV (less than 10) were recorded for the other characters inves tigated. The h2 values ranged from 37.3%, forsedimentation value, and 86.6%, for plant height, while the values of GA% ranged between 0.09 and 593.0.5% at 10%selection intensity for grain weight per spike and grain yield, respectively. The high values of heritability coupled withhigh values of genetic advance (%) were recorded by plant height, indicates the importance of the additive gene effects,so, selection would be effective in early generations for the trait. The high values of heritability coupled with moderatevalues of genetic advance (%) for harves t index and gluten index indicate selection would be a delay in later generations.