Evaluation of diversity of bread wheat genotypes under different moisture condi-tions using diverse statistical methods

  Drought stress and water availability restrictions have always been the most important issue in agriculture in the world and Iran, and this is the most important factor in reducing plant production and Determination and identification of effective factors on wheat seed yield under water deficient condition is very important.
Iran with were an average rainfall of 240 mm per year is among the arid and semi-arid areas of the world, with this precipitate, the main factor influencing the plant's performance is drought stress. In dry and semi-arid regions due to peripheral dryness and available moisture constraints, the yield of wheat plants decreases dramatically. According to meteorologists, dry weather can occur when rainfall is less than the average of long-term rainfall in a long period of time. However, from the agricultural point of view, if the distribution of rainfall is so low that it causes a significant reduction in the yield of plants, then land has occurred. Considering the importance of wheat as an important and strategic product in Iran, due to the droughts that are occurring (precipitation below the normal level), The purpose of this study was to study the response of some cultivars of genotypes in Asadabad city to the end of the drought stress, identification of higher yield genotype (s) and also determining the characteristics that affect the yield of the present research. In order to This study was designed to investigate the genetic diversity and relationships between yield and related other traits (Study of irrigation and correlation of some physiomorphological traits with wheat yield) in 17 wheat genotype and were investigated at completely randomized design with three replications in 2009-2010 under two conditions (drought stress and non-drought stress). An experiment was conducted at the experimental field of the payame Noor University of Asadabad and the agricultural group laboratory located at the provincial lab. Each plot consisted of 5 lines 2 meters long with a distance of 20 cm and a plot distance of 50 cm. Irrigation was carried out in conditions without drought stress according to the custom of the area, However, under irrigation conditions, irrigation was not done and weed combat was carried out manually and in one step (the first stage of stemming). The harvest took place in the middle of July 2011. In order to carry out notes on the study of traits, five genotypes were randomly selected in each replicate. 14 agro-morphological traits were including (Yield stress, Yield potential, Number of Seed Per Spike, Spike Length, Flag leaf Length, Width leaf Length, 100 Kernel Weight, Plant Height, Relative Water Content, Relative Water Loss, SPAD, Area flag leaf and Single Seed weight) measured.   Analysis of variance revealed good differences among genotypes for two condition drought stress and non-drought stress. Among the traits, the highest coefficient of phenotypic variation was observed for seed yield with SPAD (drought stress condition) and seed yield with Relative Water Loss. Cluster analysis subdivided the genotypes into 3 groups. The maximum distance were observed between the genotype from groups 1 and 3. According to the comparison of mean grain yield, genotypes 7, 8 and 13 showed high yield under moisture conditions and genotype 13, 14 and 17 produced higher yields under drought stress conditions. In this study, the effects of stress have reduced the function of genotypes. However, the decreasing values in different genotypes are different, so that sensitive genotypes were with the highest yield loss and endemic genotypes with the least functional deficiency faced.