Investigate Stability and Genotypes X Environments Association in Egyptian Cotton Genotypes under Normal and Drought Condition Utilizing GGE-Biplot Model

Drought stress is one of the most important abiotic stresses in plants. This investigation aimed to study the effect of drought stress on twenty four cotton genotypes belonging to Gossypium barbadense L., in a randomized complete block design with three replications at Sakha Experimental Station, Agricultural Research Center, Kafr El-Sheikh government, Egypt, during five growing seasons from 2016 to 2020 for the two treatments normal and drought. The normal irrigation treatment was done every fifteen days as recommended to receive eight irrigations during the growing season, while drought stress treatment received only four irrigations during the plant growth cycle. The studied traits were boll weight, seed cotton yield / plant, lint yield / plant and lint %. The four studied yield traits showed highly significant differences for genotypes, environments and G x E. These results indicated that the studied genotypes were differed in their responses under both treatments. Overall, the variation was mainly attributed to environments (20.921, 24.462, 26.975 and 32.549%) followed by the genotypes (14.669, 8.509, 7.499 and 5.016%) and GEI (11.934, 15.216, 13.786 and 9.004%) for boll weight, seed cotton yield, lint yield and lint %, respectively. Phenotypic stability of the twenty four cotton genotypes was tested using GGE-biplot method across ten environments. Based on GEI and GG-biplot analysis, genotypes G5, G19 and G20 located in the mega-environments (E1, E3 and E5) were identified as the ideal genotypes with more stability and higher lint cotton yield production.