Selection for Earliness in Bread Wheat (Triticum aestivum L.) under Infertile Soil Conditions

THE CURRENT research was performed during the four growing .seasons 2010/2011-2013/2014 at the Experimental Farm of the Agronomy Department, Faculty of Agriculture, SouthValleyUniversity, Qena. This research aimed to study the response to direct selection for early heading date and the correlated response of other studied characters. Two cycles of pedigree selection for early heading date were practiced on a segregating population of bread wheat cross (SHORAWAKI BW-20313 × IG 41897 ICBW 201657) in F₃ and F₄ generations.
Results revealed highly significant difference among F₃ families for heading date and the other correlated characters. Also little differences were observed between PCV and GCV values, reflecting presence of sufficient amount of genetic variability for selection. Moreover, high estimate of broad sense heritability was observed in heading date (81.52%) in base population. After two cycles of pedigree selection for early heading date, the realized gains recorded -22.22 and -30.36 % decrease in days to heading relative to the bulk sample and better parent, respectively. Negative genotypic correlations between heading date and the other studied characters except for spike length ranged from small to moderate were observed in the base population. However, after two cycles of selection, the correlation direction was inverted, and high positive correlations between heading date and each of 100-kw and grain yield/plant (0.80 and 0.53) were observed. Pedigree selection for early heading date resulted nine earliest families and three from them no. 2, 33 and 44 taking top rank by 58.67 day. The earliest family no. 44 could be considered the best selected family because it showed 8.62 and 53.66 % increase in grain weight over the better parent and the bulk sample, respectively.