پديد آورندگان :
نيستاني، الياس دانشگاه صنعتي شاهرود , مكاريان، حسن دانشگاه صنعتي شاهرود , عامري، علي اكبر مركز تحقيقات و آموزش كشاورزي و منابع طبيعي خراسان شمالي , حيدري، مصطفي دانشگاه صنعتي شاهرود
كليدواژه :
تنش كم آبي , غلات , عملكرد دانه , ديم
چكيده فارسي :
اين پژوهش در سال زراعي 95-1394 در دو مكان (ايستگاه تحقيقات كشاورزي ديم شيروان و ايستگاه تحقيقات كشاورزي سيساب بجنورد) در استان خراسان شمالي در قالب طرح بلوك‌هاي كامل تصادفي در چهار تكرار در دو شرايط ديم (تنش) و آبياري تكميلي به اجرا درآمد. بر اساس عملكرد دانه در شرايط تنش و بدون تنش، شاخص‌هاي: حساسيت به خشكي فيشر(SSI)، شاخص تحمل به خشكي فرناندز(STI) ، شاخص پايداري عملكرد(YSI)، شاخص ميانگين بهره‌وري(MP)، شاخص ميانگين هندسي عملكرد(GMP) و شاخص عملكرد(YI) محاسبه شدند. بر اساس تجزيه واريانس مركب، اثر مكان براي اكثر صفات و عملكرد دانه معني‌دار بود و ژنوتيپ‌ها از نظر عملكرد دانه داراي اختلاف معني‌داري بودند. اثر متقابل ژنوتيپ مكان نيز براي اكثر صفات و صفت عملكرد دانه معني‌دار بود. نتايج نشان داد، ژنوتيپ‌هاي 17 و 12 به ترتيب با 2780 و 2608 كيلوگرم در هكتار عملكرد دانه در شرايط بدون تنش و با 2263 و 2119 كيلوگرم در هكتار عملكرد دانه در شرايط تنش، نسبت به ساير ژنوتيپ‌ها برتر بودند. بر اساس ضرايب همبستگي محاسبه شده، شاخص هاي تحمل به خشكي فرناندز، ميانگين بهره‌وري و شاخص ميانگين هندسي عملكرد، بيشترين همبستگي را با عملكرد دانه داشتند. ژنوتيپ‌هاي 17 و 12 از لحاظ تمام شاخص‌هاي محاسبه شده نسبت به ساير ژنوتيپ‌ها در هر دو محيط تنش و بدون تنش برتري داشتند و اين دو ژنوتيپ با بالاترين عملكرد دانه، متحمل‌ترين ژنوتيپ به خشكي نسبت به ساير ژنوتيپ‌ها شناخته شدند.
چكيده لاتين :
Introduction: Drought stress is the most restricting factor for crop production in arid and semiarid regions. Reduction of crop productivity in these regions is estimated to be more than 50%, due to climate change and global warming in recent decades (Jha et al., 2014). According to the Mediterranean precipitation pattern, in most parts of Iran, near all rainfall happens in winter season and therefore drought stress usually occurs in flowering and physiological ripening stages of wheat. Understanding the response of these plants to different environmental stresses such as drought stress and other restricting factors is inevitable. Drought resistance is a quantitative trait, which is not measurable directly. This problem appears during the identification process of resistant genotypes to drought stress. In order to discriminate resistant genotypes, some indices are recommended based on the seed yield in normal and drought conditions. The best index is the one that is able to select genotypes with high yields under water-stressed and non-stressed conditions. Shafazadeh et al., (2004) recommended that MP, GMP and STI indices are suitable for detecting drought resistant and productive genotypes because they had significant and positive correlation with seed yield in the both conditions after flowering stage. Materials and Methods This investigation was conducted using 20 improved lines of rain-fed wheat genotypes at two experimental sites including Dry-land Agricultural Research Station of Shirvan and Agricultural Research Station of Sisab, Bojnourd, Iran, during the 2015-2016 growing season. The statistical layout was a completely randomized- block design with 4 replications under water deficit (dryland farming) and complementary irrigation conditions. After harvest and yield measurements of genotypes in each growth condition, the following indices were calculated: stress susceptibility index (SSI), stress tolerance index (STI), tolerance (Tol), mean productivity (MP), geometric mean productivity (GMP), sensitivity drought index (SDI), relative drought index (RDI), yield stability index (YSI), yield index (YI), relative water content( RWC )and electrical conductivity( EC .)Data analysis was performed using Path ,SAS and MSTAT-C software .Means comparisons were done using Duncan’s test and graphs were drawn by Excel. Results and Discussion Based on the combined analysis of variances ,the effect of location was significant for all the indices .This shows that the effect of location on grain yield of genotypes was different .The interaction effect of genotype × location was not significant for grain yield under normal condition( Yp )but it was significant under stressed condition( Ys ,)indicating that under water deficit condition ,the interaction between genotype and environment is strengthened .The results showed that grain yield of the genotypes in irrigated condition for both sites was not different but grain yield of genotypes in stressed condition was different in each location. In other words ,dryland yield of genotypes differed according to different growth locations .The reason why interaction between genotype and location was nonsignificant in normal growing condition was that at the both experimental locations (Sisab and Shirvan stations ,)plants received irrigation water at the critical growth periods( flowering and grain-filling stages )and therefore did not face any moisture shortage in non-dryland growing condition at the both locations .Dryland yield of genotypes at Sisab station( Bojnourd )was higher than that of Shirvan station due to higher precipitation in Sisab .Our results showed that the effect of genotype× environment is significant and the experimented genotypes possess adequate genetic variation for selection( Mohammadi et al .)2015 ,.Genotypes No 17 .and12 with 2780 and 2608 kg.ha 1-in non-stressed and 2263 and 2119 kg.ha 1-in stressed conditions ,were respectively ,superior to the other genotypes. Conclusion Genotypes No 17 .and 12 based on the all investigated indices ,especially STI, GMP and MP were found to be superior compared to the other genotypes in both stressed and non-stressed conditions .Genotypes No 17 .and 12 produced 2780 and 2608kg .ha 1-grain yield in non-stressed condition and 2263 and 2119 kg .ha1- grain yield under stressed condition ,respectively .Therefore ,these genotypes were selected as tolerant genotypes to drought stress .Heritability of grain yield trait under drought stress is reduced due to genotype and environment interaction .Therefore ,selecting genotypes with the lowest reduction in grain yield in end-season drought stress condition would help improving grain production per unit area.
