Field Performance and Gene Expression of Drought Stress Tolerance in Cotton (Gossypium barbadense L.)

Abstract

Twenty cotton genotypes belonging to Gossypium barbadense L. were used to screen the cotton genotypes for drought stress tolerance and to study gene expression of some genes related to cotton tolerance for drought stress. According to the field performance, highly significant genetic differences were found between cotton well-watered and water-stressed treatments as well as among the twenty cotton genotypes. According to Drought Stress Index (DSI), the genotypes “10229”, “Suvin” and “Giza75” were most drought tolerant. Meanwhile, the genotypes “Giza92”, “[Giza84x(Giza70xGiza51B)xs6]” and “Giza93” were the drought moderate tolerant. On the other hand, the most drought susceptible genotype was “Giza85”. The above mentioned genotypes were used to study the gene expression of different genes related to drought stress tolerance in cotton. The gene flowering locus T-like protein 1 (FTL1) and the Gossypium heat shock protein 1 (GHSP1) have been expressed in most genotypes (with different degrees of intensity) except in the pattern of genotype “Giza85” (control and stressed) which suggest that these genes clearly discriminate the drought susceptible cotton genotypes. The general trend of the expression of Lea2A and MFT1 genes was not affected by the drought stress. No discriminate trend was obtained for the genes Lea4 D9a and Lea4 D9b, whereas, different band patterns were noted. It can be said that the most affected genes with drought stress are FTL1 and HSP1 genes and can be used to determine the drought susceptible cotton genotypes.