بررسی پاسخ به گزینش مستقیم و غیر مستقیم صفات زراعی و مراحل زایشی در شرایط تنش کم‌آبی در سویا (.glycine max l)

کارائی گزینش مستلزم شناخت کامل و دقیق مولفه‌های ژنتیکی صفات زراعی در جمعیت‌های اصلاحی است. با هدف بررسی مولفه‌های ژنتیکی صفات زراعی و زایشی، در سال 1392 در کرج، 50 ژنوتیپ سویا در دو محیط نرمال و تنش خشکی در قالب دو طرح بلوک‌های کامل تصادفی کشت گردید. در طول مراحل رشد، مراحل زایشی و پس از رسیدن محصول صفات زراعی ارزیابی و ثبت گردید. بر اساس نتایج حاصله اغلب مولفه‌های ژنتیکی در دو محیط نرمال و تنش مشابه بود. اکثر ژنوتیپ‌ها زودرس و متعلق به گروه رسیدن 1 بودند. در بین خصوصیات مراحل زایشی بیشترین و کمترین میزان پیشرفت ژنتیکی در محیط نرمال 21.40 و 3.95 درصد و در محیط تنش 21.9 و 7.3 درصد به‌ترتیب مربوط به روز تا شروع پر شدن دانه و طول نسبی مراحل زایشی بود. در محیط نرمال بیشترین پیشرفت ژنتیکی 0.52 مربوط به تعداد غلاف در بوته و تعداد شاخه فرعی و کمترین پیشرفت ژنتیکی 0.14 مربوط به تعداد گره در ساقه بود. در محیط تنش نیز بیشترین و کمترین پیشرفت ژنتیکی 104/0 و 14/0 به‌ترتیب مربوط به تعداد غلاف در بوته و تعداد گره در ساقه بود. در بین صفات زراعی در شرایط نرمال بیشترین مقادیر پاسخ به گزینش غیرمستقیم عملکرد دانه به میزان 1.6 و 1.41 گرم به ترتیب از طریق وزن صد دانه و تعداد دانه در بوته و در شرایط تنش به میزان 1.04، 0.89 و 0.87 از طریق تعداد شاخه فرعی، تعداد دانه در بوته و وزن صد دانه بدست آمد. همچنین بر اساس شاخص انتخاب ژنوتیپ ایده‌آل، پنج ژنوتیپ در گروه متحمل، هفت ژنوتیپ در گروه نیمه متحمل، 11 ژنوتیپ در گروه نیمه حساس و 27 ژنوتیپ در گروه حساس قرار گرفتند. ژنوتیپ‌های roanak، kabalovskaja و tms به‌ عنوان متحمل‌ترین و ags 363، hermen وkuban به عنوان حساس‌ترین ژنوتیپ‌ها شناخته شدند.

evaluation of response to direct and indirect selection of agronomic and reproductive stages characteristics in water deficiency stress conditions condition in soybean (glycine max l.)

introductionselection efficiency requires complete and accurate knowledge of genetic parameters such as heritability, phenotypic and genotypic variation coefficient, environmental variance, selection response, genetic gain, genetic and phenotypic variance, genetic and phenotypic correlation between traits that the breeder consciously chooses the appropriate selection method in breeding populations. in this study, some genetic parameters for yield and soybean agronomic and reproductive period characteristics under normal and stress conditions were estimated and drought tolerant genotypes are determined by the ideal genotype selection index (siig).materials and methodsin 2013, in an experimental farm in karaj, 50 soybean genotypes were cultivated in two normal and drought stress conditions in a randomized complete block design with three replications. irrigation cycle was determined based on the amount of evaporation from the surface of class a pan. during the growth period, the reproductive period characteristics and after the ripening agronomic traits were evaluated. after collecting experimental data, analysis of variance, mean, minimum, maximum values of traits, heritability, phenotypic and genotypic variation coefficient, environmental variance, selection response, genetic gain, genetic and phenotypic variance, genetic and phenotypic correlation, and siig index method was used for grouping genotypes based on drought tolerance.results and discussionamong the the reproductive period characteristics the highest and lowest genetic gain in normal conditions were 21.40 and 3.95% for day to the beginning of seed filling and the reproductive relative duration respectively and in stress conditions were 21.9 and 7.3% for day to the beginning of seed filling and the reproductive relative duration respectively.in normal conditions, the highest genetic gain was 0.52 for the number of pods per plant and the number of branches and the lowest genetic genetic gain was 0.14 for the number of nodes per stem. in stress conditions, the highest and lowest genetic gain were 104% and 0.14 for the number of pods per plant and the number of nodes per stem, respectively. in normal conditions, among the agronomic traits, the highest values of response to indirect selection of grain yield were 1.6 and 1.41 g, through 100-grain weight and number of seeds per plant respectively and in stress conditions, the highest values of response to indirect selection of grain yield were 1.04, 0.89 and 0.87, through the number of branches, number of seeds per plant and weight of 100 seeds were obtained respectively. also, according to the ideal genotype selection index (siig), five genotypes were in the tolerant group, seven genotypes in the semi-tolerant group, 11 genotypes in the semi-susceptible group and 27 genotypes in the susceptible group. roanak, kabalovskaja and tms genotypes were identified as the most drought tolerant and ags 363, hermen and kuban as the most drought sensitive genotypes.conclusionbased on the results, acceptable phenotypic and genotypic diversity in terms of agronomic traits was observed among the studied genotypes. most of the genetic parameters measured were almost identical under both normal and stress conditions. the characteristics of the reproductive period had higher e selection response (direct and indirect), higher broadsense heretability and higher genetic gain than the agronomic characteristics. the highest indirect to direct selection efficiency for grain yield were obtained from number of seeds per plant and 100-seed weight under normal conditions,and the highest indirect to direct selection efficiencies were obtained from number of sub-branches, number of seeds per plant and 100-seed weight in stress conditions. also in this study, based on the ideal genotype selection index (siig), roanak, kabalovskaja and tms genotypes were identified as the most tolerant and ags 363, hermen and kuban as the most sensitive genotypes.