مطالعه نحوه توراث تعدادي از صفات كمي در گندم نان

Inheritance of Some Quantitative Traits in Bread Wheat (Triticum aestivum)

Grain yield is a complex trait made up of interaction among different yield components, and environmental effects. Because of these complex interactions, it is difficult to improve yield through breeding (especially in the early generations) if yield is the only factor recorded, suggesting that component traits should also be taken into account as selection criteria for yield improvement. This is the reason why it is necessary to know the genetic architecture of yield components. The objective of this investigation was to study inheritance of the quantitative traits in bread wheat by using generations mean analysis (GMA). Two inbred linnes (line 14 & line 30) were crossed to produce the Fj generation. The resulting F] plants were selfed as well as backcrossed to both parents to produce F2 and backcross generations . All generations (Parents, Fi, F2, BCi and BC2) were planted in the research field, University College of Agriculture and Natural Resources, University of Tehran, in a Randomized Complete Block Design with three replications. GMA was performed through scaling test which essays all generations simultaneously. In most cases a digenic epistatic model was sufficient to explain variation in generation means. . Gene effects including additive and dominance effects, epistasis effects of additive x additive, additive x dominance, and dominance x dominance were observed. For plant height and 1000 kernel weight the additive- dominance effects; for kernel no/spike, dominance, additive x additive, and dominance x dominance effects; for kernel wt/plant dominance, additive x additive, additive x dominance, and dominancex dominance effects, and for other traits the epistasis effects (specially additive x additive, and dominance x dominance) were distinguished as the most important effects in controlling these traits.The highest (76%) and lowest (40%) narrow sense heritabilities were obtained for plant height, and spike weight, respectively.