شناسايي ژنوتيپ هاي كلزا متحمل به خشكي با استفاده از شاخص انتخاب ژنوتيپ ايده آل

Identifying drought Tolerant Canola Genotypes using Selection Index of Ideal Genotype

تنش خشكي يكي از مهم­ترين تنش ­هاي غير­زنده مي­ باشد كه رشد، متابوليسم و عملكرد گياهان زراعي را در سراسر دنيا تحت تاثير قرار مي ­دهد. اين تحقيق به­منظور شناسايي ژنوتيپ­هاي كلزا متحمل به خشكي با استفاده از شاخص­ هاي مختلف تحمل به خشكي در مزرعه مركز تحقيقات كشاورزي و منابع طبيعي يزد انجام شد. دو سطح آبياري شامل آبياري براساس 80 ميلي­متر تبخير از سطح تشتك تبخير كلاس A (به­عنوان تيمار شاهد)، قطع آبياري از ابتداي مرحله گل­دهي كه در كرت اصلي قرار گرفت و 21 ژنوتيپ و لاين دبل هاپلوئيد كلزا در كرت فرعي، به ­صورت طرح كرت ­هاي خرد­شده در قالب طرح بلوك هاي كامل تصادفي با سه تكرار مورد بررسي قرار گرفتند. شش شاخص تحمل به خشكي شامل شاخص حساسيت به خشكي، شاخص تحمل تنش، شاخص تحمل، ميانگين هارمونيك، ميانگين توليد، ميانگين هندسي عملكرد بررسي شد و هم­چنين شاخص انتخاب ژنوتيپ ايده­ آل بر مبناي شاخص ­هاي مختلف تحمل به خشكي (STI، GMP، SSI، MP، TOL و HM) و صفات فيزيولوژي محاسبه شد. نتايج نشان داد تنش آبي تأثير منفي بر عملكرد دانه، اجزاي عملكرد، ارتفاع بوته و تعداد شاخه ­هاي ثانويه كلزا داشته است. بر مبناي شاخص SIIG، ژنوتيپ­ هاي SLM046 و Adriana به­ ترتيب با بيش­ترين مقدار SIIG (به ­ترتيب 791/0 و 756/0) به ­عنوان ژنوتيپ­ هاي اميدبخش در شرايط تنش خشكي معرفي شدند و مي ­توانند ژنوتيپ­ هايي مناسب براي مناطق خشك باشند. اين نتايج را نمودار سه بعدي نيز تاييد نمود. در مجموع شاخص SIIG يك روش مناسب براي شناسايي ژنوتيپ­ هاي متحمل به تنش با استفاده از ساير شاخص­ هاي مختلف تحمل به خشكي و صفات مرفولوژيك مي ­باشد.

Drought stress is one of the most important abiotic factors which adversely affects growth, metabolism and yield of crops worldwide. The goal of the research was identify drought tolerate canola genotypes using the different drought tolerance indices. The experiment was conducted as split plot based on randomized complete block design with three replications at the experimental farm of agricultural and natural resources research center, Yazd, Iran .Two irrigation levels consisting of irrigation after 80mm evaporation from class “A” pan as control, no irrigation from flowering stage were applied in main plots and subplots were 21 winter canola cultivars/double haploid. Six drought tolerance indices, including stress tolerance index (STI), geometric mean productivity (GMP), stress susceptibility index (SSI), mean productivity (MP), stress tolerance (TOL), harmonic mean (HM) were used and calculated for all treatments. Then selection index of ideal genotype (SIIG) based on both tolerance indices (STI, GMP, SSI, MP, TOL, and HM) and morphological traits were defined and calculated. Selection index of ideal genotype (SIIG) is a decision making method that is very simple to implement. The results showed water stress negatively affected yield and yield components, plant height, and number of branches of rapeseed genotypes. Based on the results "SLM046" and "Adriana" with maximum SIIG (0.791 and 0.756) were identified as the most ideal genotypes among assessed genotypes. As "SLM046" and "Adriana" genotypes were superior to the other genotypes under drought condition, they can be considered as promising genotypes for drought regions. These results were also approved by three dimensional scatter graphs. It is concluded that selection index of ideal genotype (SIIG) could be serve as an appropriate index to identify drought tolerance genotypes based on a set of drought stress tolerance indices and morphological traits in crops.