Genetic analysis for some of quantitative traits in bread wheat under normal and drought stress conditions

The study of genetic of drought resistance has always been challenging for plant breeders. Understanding the genetic control of traits associated with yield helps breeders to utilize their germplasm in a more efficient and consistent manner and to make good choices in breeding programs. The current study was aimed to investigate the genetic control of some quantitative traits in bread wheat (Triticum aestivum L.) and to examine the related changes across normal (full irrigation) and drought stress conditions. For this purpose, six generations derived from a cross between two lines (Bezostaya as tolerant parent and 518 as a susceptible parent) were evaluated for grain yield (GY), plant height (PH) and peduncle length (PL) as well as spike length (SL), thousand grain weight (TGW) and harvest index (HI) using randomized complete block design with four replicates. Generation mean analysis indicated that non-allelic interactions were important factors in controlling the expression of these characters. The results indicated that GY under drought condition, PL under full irrigation and drought stress conditions and PH, SL and HI under full irrigation condition were governed with additive gene effects. The PL and TGW were influenced by additive and over dominance gene effects under both irrigation conditions, respectively and no behavioral changes occurred. In general, selection in early segregating generations may be useful for those traits that are affected by additive gene effects.