گزینش ژنوتیپ‌های گندم دوروم (triticum turgidum l. var. durum) متحمل به تنش خشکی انتهای فصل با استفاده از شاخص‌های چند صفتی (mgidi)

وقوع تنش خشکی در انتهای فصل یکی از عوامل مهم کاهش عملکرد در گندم دوروم می باشد. به منظور شناسایی ژنوتیپ‌های متحمل به تنش خشکی، تعداد 17 لاین امیدبخش گندم دوروم در ایستگاه تحقیقات کشاورزی داراب در قالب طرح بلوک های کامل تصادفی با سه تکرار به مدت دو سال زراعی (1400-1399 و 01-1400) در شرایط بدون تنش و تنش خشکی (قطع آبیاری در مرحله گل دهی) مورد ارزیابی قرار گرفتند. نتایج نشان داد که شاخص انتخاب ژنوتیپ مطلوب (siig) و شاخص ترکیب شاخص های معنی دار (csi) همبستگی مثبت و معنی داری با عملکرد دانه در شرایط بدون تنش (yp) و عملکرد دانه در شرایط تنش (ys) داشتند. شاخص فاصله  ژنوتیپ- ایدئوتیپ چند صفتی (mgidi) همبستگی منفی و معنی‌داری با yp و ys داشت. براساس نتایج تجزیه به مولفه های اصلی، ژنوتیپ های گندم دوروم در چهار ناحیه نمودار بای پلات قرار گرفتند. ژنوتیپ‌های ناحیه یک (لاین‌های 5، 7، 9، 12 و 15) دارای عملکرد دانه پایین در هر دو شرایط تنش و بدون تنش بودند. ژنوتیپ‌های ناحیه دو (ارقام و لاین‌های 1، 2، 14 و 19) دارای عملکرد دانه بالا در شرایط بدون تنش بودند. ژنوتیپ های ناحیه سه (لاین‌های 6، 10، 13، 17 و 18) دارای عملکرد دانه بالا در هر دو شرایط تنش و بدون تنش بودند و انتخاب ژنوتیپ های برتر از این ناحیه انجام شد. شاخص های میانگین بهره‌وری (mp)، میانگین هندسی بهره‌وری (gmp)، میانگین هارمونیک عملکرد (hm) و شاخص تحمل به تنش (sti) که در ناحیه سه نمودار pca قرار داشتند، از نظر شناسایی ژنوتیپ‌های پرمحصول و متحمل به تنش خشکی، نسبت به سایر شاخص‌ها برتری داشتند. ژنوتیپ های ناحیه چهار (ارقام و لاین‌های 3، 4، 8، 11، 13، 15 و 20) دارای رتبه عملکرد دانه بهتری در شرایط تنش بودند. براساس نتایج این تحقیق، شاخص‌های mgidi، csi و siig کارایی لازم جهت انتخاب ژنوتیپ های پرمحصول و متحمل به تنش را به طور همزمان داشتند. نتایج شاخص های  siig، mgidi و csi  مشابه بود و ژنوتیپ‌های 2، 10، 17 و 18 انتخاب شدند، ولی براساس هر سه شاخص تنها لاین 18 در رتبه اول قرار گرفت. بنابراین، لاین 18 که در ناحیه سه نمودار pca قرار گرفته و دارای عملکرد دانه بالاتر از میانگین کل، هم در شرایط تنش و هم در شرایط بدون تنش بود، به عنوان ژنوتیپ متحمل به تنش خشکی برای توسعه کشت در منطقه داراب و سایر مناطق با شرایط مشابه، شناخته شد. 

selection of durum wheat (triticum turgidum l. var. durum) genotypes tolerant to terminal season drought stress using multi-trait indices (mgidi)

introduction: drought stress constaints crop production in the world. terminal season drought stress is one of the important environmental factors of yield reduction in durum wheat in semi-arid regions. therefore, high yielding genotypes with drought tolerance is an efficient approach to mitigate its adverse effects. with declining resources of water and escalating intensity of drought, yield loss is an alarm in semi-arid regions. however, development of drought tolerance depends on complex traits and their interaction with environmental factors. likewise, choosing genotypes with drought tolerant is a tricky task. alternatively, some statistical parameters as well as drought tolerance indices can be employed to compare the changes in grain yield in normal and drought stress conditions for identification of high yielding genotypes with drought tolerance.material and methods: to identify terminal season drought-tolerant genotypes, 17 promising genotypes of durum wheat were evaluated at the darab agricultural research station, iran. the evaluation was conducted in randomized complete block design with three replications and over two cropping seasons (2020-2022), both under non-stress conditions and terminal drought stress conditions by irrigation withdrawal at the flowering stage (gs 60). the indices of drought tolerance studied were yield under non-stress conditions (yp); yield under stress conditions (ys); tolerance index (tol); stress susceptibility index (ssi); mean productivity (mp); geometric mean productivity (gmp); stress tolerance index (sti); harmonic mean (hm); percentage of yield decrease (r%); yield index (yi); yield stability index (ysi); relative drought index (rdi); abiotic-stress tolerance index (ati); stress susceptibility percentage index (sspi); stress non-stress production index (snpi). siig (selection index of ideal genotype), csi (combination of significant indices) and mgidi (multi-trait genotype-ideotype distance index) indices were used in order to integrate different indices of drought tolerance and better selection of drought tolerant genotypes. results: the results of combined analysis of variance for grain yield under non-stress and terminal season drought stress conditions indicated that the effects of year, environment and genotype on grain yield were significant. additionally, the heatmap analysis revealed that the lowest observed grain yield was associated with terminal season drought stress conditions in the 2020-2021, while the highest observed grain yield occurred in the 2021-2022 under non-stress conditions. furthermore, the highest grain yield (kg.ha-1) under normal irrigation conditions (yp) was observed for genotypes 2 (8178), 1 (7938), 17 (7698), 19 (7662), 18 (7659), 14 (7451), and 10 (7413), respectively. on the other hand, the highest grain yield (kg.ha-1) under drought stress (ys) was related to genotypes 18 (5639), 4 (5489), 8 (5479), 10 (5473), 13 (5434), and 6 (5404), respectively. moreover, based on the tol, ati, and sspi indices, genotypes 9, 4, 12, and 15 with the lowest values of these indices were identified as stress-tolerant genotypes. in addition, based on the ssi and %r indices, genotypes 4 and 8, which had the lowest values of these indices, respectively, were also classified as stress-tolerant genotypes. examining the mp, gmp, and hm indices revealed that genotypes 2, 18, 1, 17, and 10 exhibited the highest values and were identified as the best-performing genotypes, respectively. similarly, based on the snpi index, genotypes 4, 8, 18, 13, and 6 demonstrated the highest values and were among the drought tolerant genotypes. the results also showed that the genotypes 18, 4, 8, 10, and 13 had the highest values of the yi index, respectively. the results revealed that the siig and csi indices had positive and significant correlation with yp and ys. conversely, mgidi index had negative and significant correlation with yp and ys. the results of principal component analysis (pca) revealed that the investigated genotypes were placed in four areas of the biplot diagram. the genotypes of area one (5, 7, 9, 12 and 15) exhibited low yield potential under both non-stress and stress conditions. the genotypes of the second region (1, 2, 14 and 19) showed high grain yield potential under non stress conditions. the genotypes of the third region (6, 10, 13, 17 and 18) demonstrated high yield potential under both non-stress and stress conditions, leading to their selection as superior genotypes. therefore, mp, gmp, hm and sti indices were positioned within the area of the three pca diagrams, proved suitable in identifying high yielding and drought tolerant genotypes. furthermore, genotypes in fourth area (3, 4, 8, 11, 13, 15 and 20) displayed higher grain yield under terminal season drought stress conditions. conclusion: the results of this experiment showed that mgidi, csi and siig indices had sufficient efficiency in selecting high yielding and tolerant durum wheat genotypes. efficiency of siig, mgidi and csi indices in selection of high yielding terminal drought tolerant genotypes were similar, and genotypes 2, 10, 17 and 18 were selected. however, based on all three indices, only genotype 18 ranked first. therefore, genotype 18 which was located in the third area of pca diagram and performed higher than average grain yield under both and non stress and stress conditions, was identified as adapted drought tolerant genotype for the darab region and similar areas.