Identification of QTLs and impact of selection from various environments (dry vs irrigated) on the genetic relationships among the selected cotton lines from f₆ population using a phylogenetic approach

Severe drought on cotton plants can slow plant development and cause small bolls and squares to shed. Establishment and prebloom irrigations affect total yield, but water deprivation following bloom and into boll development also affects lint quality. The impact of selection from various environments (dry vs irrigated) on the genetic relationships among the selected cotton lines from F₆ population was studied using a phylogenetic approach. It seems that these lines have already evolved different adaptations to drought as a result of their selection environment and it is assumed that different introgression have been stabilized under each environment. Some QTLs were mapped for drought under selected environment, that is, well watered and dryland condition. One QTL (BNL1693) was for seed cotton (SC) on chromosome 1 and 15, while 2 more QTLs (BNL1153 and BNL2884) for SC were identified on Chr6. 3 QTLs, BNL3259, BNL1153 and BNL2884 for osmotic potential were mapped on Chrs 14, Chrs25 and Chr6 respectively. Consistent QTLs for drought resistance traits and yield under drought were detected and can be useful for marker-assisted selection for cotton improvement under drought conditions.