The study of drought stress effects on yield and yield components of cotton using biplotanalysis

In order to evaluate the effect of drought stress on yield and yield components of cottonand selection of the best cultivars, an experiment was conducted as complete randomized block design (RCBD) with three replications on 14 cotton cultivars at Agricultural Research farm of Technical and Vocational Training center, Nehbandan, Khorasanjonobi under normal irrigation and drought stress in 2012. The results of variance analysis showed that there was significant difference among cultivars for all traits under stress and non-stress conditions. The effects of drought stress was significant on day number to flowering, plant height, number of sympodial branches, cotton yield, number of boll per plant and lint percentage. The assessment of simple correlation coefficient showed that the yield was positively and significantly correlated number of bolls per plant, number of sympodial branch, plant height and lint percentage. The traits of plant height, number of sympodial branches, day number to flowering, lint percentage and number of bolls per plant can be considered as the best indices for yield improving. In analysis of biplots, traits of numbers of sympodial branches and bolls per plant were as distinguishing traits and cotton yield was as traits representative. Also cultivars of Varamin, Bakhtegan, Mehr and Sahel had more stable yield. Varamin cultivar was similar to ideal cultivar.