بررسی تنوع صفات زراعی و مورفولوژیکی لاین های دابلدهاپلویید گندم با استفاده از روش های آماری چند متغیره

در این تحقیق تنوع صفات زراعی و مورفولوژیکی تعداد روز تا ظهور سنبله، روز تا رسیدگی فیزیولوژیک، طول سنبله، تعداد سنبلچه، تعداد دانه در سنبله، وزن دانه در سنبله، وزن هزار دانه، ارتفاع گیاه، تراکم دانه در سنبله و عملکرد دانه 150 لاین دابلدهاپلوییدگندم در قالب طرح آگمنت مورد بررسی قرار گرفت. محاسبه ضرایب تغییرات فنوتیپی بیانگر وجود تنوع ژنتیکی بالایی در اکثر صفات مورد مطالعه بود. برآورد همبستگی اجزاء عملکرد نشان داد که عملکرد دانه با صفت وزن هزار دانه دارای همبستگی مثبت و با صفات تعداد روز تا ظهور سنبله، روز تا رسیدگی فیزیولوژیک و تعداد سنبلچه در سنبله دارای همبستگی منفی و معنی دار بود. بررسی تحلیل عاملی نشان داد که عوامل موثر بر خصوصیات سنبله (تعداد دانه در سنبله، وزن دانه و تراکم دانه در سنبله)، زود رسی (تعداد روز تا ظهور 50 درصد سنبله و تعداد روز تا رسیدگی فیزیولوژیک) و ارتفاع (تعداد سنبلچه در سنبله، طول سنبله و ارتفاع گیاه) باهم 70/55 درصد از واریانس داده‌ها را در بر داشتند. برآورد عملکرد دانه در روش رگرسیون گام به گام مشخص نمود که وزن هزار دانه مهم ترین مولفه‌ای بود که ارتباط نزدیک‌تری با عملکرد دانه داشت و به تنهایی 10/3 درصد از تغییرات آن را توجیه می‌کرد. تجزیه علیت برای صفت عملکرد دانه نشان داد که وزن هزار دانه و طول سنبله بالاترین اثر مستقیم را بر عملکرد دانه داشتند. نتایج نشان داد که تعدادی از لاین‌های مورد بررسی دارای عملکرد و صفات زراعی و مورفولوژیکی برتری نسبت به والدین و شاهدهای آزمایش بودند.

evaluation of variability of agronomic and morphological traits in doubled haploid wheat lines using multivariate statistical methods

to date, wheat counts as one of the most important cereal grains, feeding theincreasing world population (feldmann, 2001). evaluation of the genetic diversityof wheat genotypes will provide a great opportunity to improve its yield qualityand increase its grain output. the results of previous studies on wheat have showncorrelations among grain yield and its components such as number of tillers,spike length, grain number per spike, thousand-kernel weight and harvest index.however, because of complex relations among different traits and their interactionswith grain yield of wheat, simple correlations of these traits can not be directly andunequivocally used to clarify those relationships. therefore, different statisticaltechniques can be employed in modeling the crop yield, including correlation,regression, path analysis, factor analysis, factor components, and cluster analysis(leilah & al-khateeb 2005). the goal of this study was to identify variability ingrain yield and some agronomic and morphological traits and their relationship among 150 doubled haploid wheat lines.materials and methodsin this study, morphological and phenotypic traits of 150 doubled haploidwheat lines derived from three different crosses: 1) dh-26: ghods*3/mv17, 2)dh-27: flanders/3*ghods, 3) dh-28: hybrid bersee/*3ghods, which consistedof 75, 45 and 30 individuals, respectively, were evaluated. the experiment wasconducted using an augmented design with six check cultivars including parsi,mihan, bolani, ghods, hybrid bersee and mv17, which were repeated over fiveblocks. some agronomic traits such as days to %50 of flowering, days to maturity,spike length, number of spikelets per spike, number of grains per spike, grainweight per spike, thousand kernel weight, plant height, grain density per spike andgrain yield of dh lines as well as check cultivars were evaluated. dh lines wereclassified with hierarchical cluster analysis using ward method as well as usingmultivariate statistical methods such as factor analysis, stepwise regression andpath analysis. statistical procedures were carried out using sas 9.0 and spss 16software packages.results and conclusionthe analysis of variance showed that there were significant differences for daysto %50 of flowering, days to maturity, spike length, number of spikelets per spike,number of grains per spike, grain weight per spike, thousand kernel weight, plantheight, grain density per spike and grain yield. the determination of coefficientsof variations for phenotypic and physiological traits of all three dh populationsindicated that most of the studied traits had a high genetic variability. evaluationof grain yield among different population showed that dh-26 population withan average grain yield of 4.885 t/ha had higher grain yield compared to othertwo populations, although within each population several lines with higher yieldsand superior agronomic and morphological traits than their parents and controlcultivars were identified. the coefficients of correlations among yield componentsshowed that grain yield had a positive and significant correlation with grain weightper spike and thousand-kernel weight while its correlation with days to 50% offlowering, days to maturity and number of spikelets per spike was negative and significant. the results of factor analysis indicated that three major factors effectiveon earliness, spike and plant height explained %68.47 of the total variation. theresults of stepwise regression analysis showed that thousands kernel weight had themost important effect on grain yield and explained 8.8% of the variation. the pathanalysis of data indicated that, number of spikelets per spike and thousand-kernelweight had the highest direct effects on grain yield. the current genetic variabilityof dh lines, which are derived from parents with good agronomic traits, especiallyyellow rust resistance (bakhtiar et al., 2015), can be employed for the selection ofthe superior genotypes that possess all beneficial characteristics.