Genetic analysis of traits related to grain yield in wheat under drought stress condition by generation mean analysis

به منظورمطالعه ي وراثت برخي صفات وابسته به عملكرد گندم نان درشرايط تنش خشكي، نسل هاي F3 ,F2 و F4 حاصل از تلاقي ارقام خارچيا درگاسپارد به همراه والدين مذكور در يك طرح بلوك هاي كامل تصادفي با دو تكرار مورد ارزيابي قرارگرفتند. طول ساقه، عملكرد بيولوژيكي، وزن خوشه ي اصلي، وزن كل خوشه ها، عملكرد دانه و هم چنين شاخص برداشت درنسل هاي مختلف اندازه گيري شدند. نتايج تجزيه ي واريانس تفاوت معني داري را براي ميانگين مربعات نسل‌ها درهمه ي صفات نشان داد. بنابر اين، تجزيه ميانگين نسل ها براي تمامي صفات مورد بررسي انجام شد. مدل چهار پارامتري شامل [d], [h], [i] و m براي اكثر صفات مشاهده شد. اگر چه هر دو نوع اثرات افزايشي و غالبيت دركنترل صفات مورد بررسي نقش داشتند، اما جز غالبيت تاثيربيشتري نسبت به اثر افزايشي نشان داد. اثرات غالبيت و اپيستازي از نوع افزايشي در افزايشي از اثرات افزايشي و هم چنين ساير انواع اپيستازي مهم تربودند. باتوجه به وجود اثرات افزايشي وغير افزايشي دركنترل صفات مورد مطالعه، انتخاب دوره اي به دنبال اصلاح شجره اي براي بهبود تحمل به خشكي در گندم نان مفيد مي باشد.

In order to study the inheritance of some traits related to grain yield in drought stress conditions in bread wheat (Triticum aestivum L.), F2, F3 and F4 generations derived from a Kharchia (tolerant) × Gaspard (susceptible) cross and their parents were used separately in a complete randomized block design with two replications. Stem length, biological yield, main spike straw weight, total spike straw weight, grain yield as well as harvest index were measured in different generations. The results of the analysis of variance showed that generations mean squares were significant for all traits. Therefore, the generations mean analysis was performed for all of the traits. The model of four-parameter including m, [d], [h] and [i] was significantly fitted for the majority of the traits. Although both types of additive and dominance effects were involved in the control of the studied traits but dominant component was more effective than the additive one. Dominance effects and additive × additive epistasis were more important than additive effects and other epistasis components for most traits. Regarding the existence of additive and non-additive effects in controlling studied traits, the recurrent selection followed by pedigree breeding can prove useful in improving drought tolerance in bread wheat.