DIRECT SELECTION FOR EARLY HEADING AND CORRELATED RESPONSE IN GRAIN YIELD AND ITS COMPONENTS OF BREAD WHEAT (Triticum aestivum L.) | ||||
| Journal of Plant Production | ||||
| Article 5, Volume 29, Issue 3, March 2004, Page 1197-1203 PDF (136.12 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2004.238516 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| G. A. R. EI-Sherbeny, | ||||
| Dept. of Agric. Botany (Genetics), Sohag Faculty of Agric., South Valley Univ., Sohag, Egypt. | ||||
| Abstract | ||||
| Effect of two cycles of direct selection on early heading and correlated response in yield components were studied in the F3 generations of a cross between Gemmeiza 3 and Sids 1 cultivars. Significant genotypic variations among the F3 families were obtained for heading date and yield components. Estimates of genotypic and phenotypic coefficients of variability showed the presence of sufficient variability for direct selection for all studied traits. Estimates of broad sense heritability were relatively high and ranged from 65.06% for grain yield per plant to 73.94% for number of spikes per plant, indicating that the proportion of genetic effects were greater than those of environment. Heading date revealed positive genotypic correlations with number of spikes per plant (0.41) and grain yield per plant (0.39). Whereas, the genotypic correlation between heading date and 1000- grain weight was negative (- 0.37). These finding indicates that selection for early heading may slightly decrease number of spikes per plant and grain yield per plant. After two cycles of selection in the F3 families, the genotypic and phenotypic coefficients of variability decreased rapidly for all studied traits. Consequently, the values of broad sense heritability reduced from 73.6% and 65.1% to 47.4% and 48.1% for heading date and grain yield per plant, respectively. These results showed that two cycles of selection in the F3 generations exhausted the genetiC variation and further selection will not be effective. The results of observed gain after two cycles of direct selection showed that days to heading was reduced by 9.1 and 7.0 days from F3 bulk families and the earliest parent, respectively. Direct selection for early heading was accompanied with a slightly decrease of 2.5 and 3.4 gm. in grain yield per plant after two cycles of direct selection compared to the F3 bulk families and the better parent, respectively. Although the reduction after two cycles of selection in yield components, some early families still had high grain yield over both F3 bulk families and better parent. The early high yielding lines obtained from this study could be used in developing new wheat varieties for cultivation in new reclaimed areas, in Upper Egypt, where the water supply is limited. | ||||
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