ارزیابی شاخص‌های تحمل به تنش خشکی هیبریدهای حاصل از تلاقی ارقام تجاری سیب‌زمینی

در راستای ارزیابی شاخص های تحمل به خشکی تعداد 12 هیبرید حاصل از تلاقی ارقام تجاری سیب زمینی، آزمایشی در قالب طرح بلوک های کامل تصادفی در سه تکرار در دو سطح آبیاری (تامین 100 و 65 درصد نیاز آبی) در گلخانه شرکت کشاورزی زرع گستر آرتا اجرا شد. نتایج تجزیه واریانس وجود تنوع در بین 12 هیبرید حاصل از تلاقی را نشان داد. در تیمار تامین 100 درصد نیاز آبی بیشترین عملکرد غده با میانگین 53.55 تن در هکتار مربوط به هیبرید r12 (♀luca×esprit♂) بود. بیشترین عملکرد غده در شرایط تامین 65 درصد از نیاز آبی معادل با 34.41 و 35.47 تن در هکتار مربوط به هیبریدهای s13 (♂luca×esprit♀) و s14 (♂luca×esprit♀) بود. در شرایط تنش بیشترین عملکرد غده و نیز بیشترین میانگین شاخص های تحمل به خشکی mp, gmp و tol مربوط به هیبرید r14 (♀luca × esprit♂) بود. نتایج بای پلات نشان داد که دو هیبرید r14 (♀luca×esprit♂) و s13 (♂luca×esprit♀) در مجاورت بردارهای مربوط به شاخص های مهم تحمل به خشکی mp, gmp و tol قرار دارند و توزیع هیبریدها در فضای بای پلات حاکی از وجود تنوع ژنتیکی بین هیبریدها نسبت به تنش خشکی است. بیشترین فاصله ژنتیکی به‌دست‌آمده از تجزیه خوشه ای بین دو هیبرید r14 (♀luca × esprit♂) و r12 (♀luca×esprit♂) و هیبرید حساس s12 (♂luca × esprit♀) است. نتایج به‌دست‌آمده از تحلیل همبستگی بین عملکرد غده در تیمار تامین 100 درصد نیاز آبی و تامین 65 درصد از نیاز آبی معادل و شاخص تحمل به خشکی نشان داد که دو شاخص mp و gmp مناسب‌ترین شاخص ها برای تعیین هیبریدهای متحمل به تنش در سیب زمینی می باشند.

Evaluation of drought tolerance indices of hybrids from potato commercial cultivars

Introduction‌Potato (Solanum tuberosum L.) is one of the most important crop plants in the world. Different indices have been introduced to determine stress tolerance, but in general, indices that are highly correlated with yield under both stress and nonstress conditions are considered as the best indices. Because these indices are capable of identifying high yield genotypes in both stress and nonstress environments, they can be used to estimate yield stability. Therefore, the purpose of this study was to compare different drought tolerance and susceptibility indices and group hybrids from potato cultivars in Ardabil province based on these indices. Materials and methods In order to study drought tolerance indices of 12 hybrids obtained from crossover of experimental potato cultivars in a randomized complete block design with three replications at two irrigation levels (100 and 65% of plant water requirement) in Zareh Agricultural Company greenhouse Gostar Arta was performed. The first year was for genetic variation, and the second year was for greenhouse cultivation. Drought tolerance indices were also calculated for the studied genotypes in order to determine the tolerance of cultivars to different water deficit conditions. The susceptibility and stress tolerance indices (GMP, MP, STI, SSI and TOL) were used to evaluate drought tolerance and drought resistance of potato genotypes.Drought tolerance indices were calculated and after computing the indices, these indices were analyzed and compared with 100% and 65% water requirement using SPSS22 software. Relationship between gland function in two environments and calculated tolerance indices were performed and threedimensional graphs were plotted using SPSS22 software. Minitab15 software was used for better evaluation of relationships by principal component analysis and biplot charts. Also, WARD method was used to select the desired hybrids for hybridization and the obtained results were obtained. A dendrogram chart form was provided. The dendrogram was plotted by Minitab15 software. Results and discussion Results of analysis of variance of yield under normal conditions and 65% water use and stress tolerance indices showed variation among 12 hybrids from crosses. Under normal conditions (100% plant water requirement) the highest yield of tuber with average of 53.55 ton /h belonged to R12 hybrid (♀Luca×Esprit♂). The highest tuber yield under drought stress conditions (65% plant water requirement) was observed in S13 (♂Luca×Esprit♀) and S14 (♂Luca × Esprit♀) hybrids with 34.41 and 35.47 ton / ha, respectively. In stress conditions (65% plant water requirement) the highest tuber yield and the highest harmonic mean, geometric mean yield and stress tolerance index belonged to hybrid R14 (♀Luca × Esprit♂). The results of correlation analysis showed tuber yield under normal and stress conditions (65% of available water) and drought tolerance index, Geometric mean productivity index and average productivity index are the most appropriate indices for determining potatotolerant hybrids. Multivariate biplot charts showed that the two hybrids R14 (♀Luca × Esprit♂) and S13 (♂Luca × Esprit♀) were adjacent to vectors related to important drought tolerance indices namely productivity mean, geometric mean productivity And stress tolerance. Also distribution of hybrids in biplot showed genetic variation among hybrids relative to drought stress. Cluster analysis showed that the highest genetic distance was between R14 (♀Luca × Esprit♂) and R12 (♀Luca×Esprit♂) hybrids and S12 (♂Luca × Esprit♀) susceptible hybrids. Conclusions Based on the results, it can be concluded that the ability of separation of drought tolerant hybrids from potato cultivars by geometric mean productivity and average productivity index and tolerance index is more appropriate and two hybrids R14 and S13 can be used as stress tolerant hybrids.