منیره نظری - Department of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
خلیل زینلی نژاد - Department of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
آندریاس برنر - Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany.
محمدهادی پهلوانی - Department of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.

Genetic diversity is a base for the survival and improvement of crops. This experiment was conducted to evaluate genetic diversity among ۴۰۰ bread wheat genotypes based on nine quantitative yield-related traits. The results of descriptive statistics showed that the highest and lowest amount of phenotypic variation belonged to kernel weight per spike (۳۴.۶۱%) and kernel length (۷.۶۱%), respectively. Correlation coefficient analysis showed a strong and positive correlation between kernel weight and spike weight (۰.۹۷) followed by the number of kernels per spike and number of kernels per spikelet (۰.۹۱). Principal component analysis reduced the nine traits into three principal components that explained ۸۵ percent of the total variation. Factor analysis revealed three underlying factors that explained ۸۶ percent of the variation. Cluster analysis based on all the studied traits divided the genotypes into four clusters. The first cluster included ۱۴۵ genotypes and had the lowest means for most of the traits. The second cluster included ۴۳ genotypes and had the highest mean for kernel length. The third cluster included ۷۷ genotypes that had the highest means for spike weight, kernel weight per spike, kernel width, and thousand-kernel weight. The fourth cluster included ۱۳۵ genotypes and had the highest means for spike length, number of spikelets, kernels per spikelet, and kernels per spike. The results of this study can contribute to the understanding of genetic diversity among bread wheat genotypes and can be used for bread wheat improvement programs.

Bread wheat, Genetic diversity, Morphological traits, Multivariate analysis