Multivariate analysis of drought tolerance in wheat substitution lines

To locate the genes controlling drought tolerance and screening quantitative indices of drought tolerance, wheat substitution lines of Cheyenne (Donor) in the genetic background of Chinese Spring (Recipient) were tested in a completely randomized block design with three replications under two different water regimes (irrigated and rainfed) in the Agricultural Research Station of College of Agriculture, Razi University. Based on the yield potential (Yp) and stress yield (Ys) quantitative criteria of drought tolerance such as: mean productivity (MP), tolerance index (TOL), geometric mean productivity (MP), stress susceptibility index (SSI) and stress tolerance index (STI) were calculated. The results of analysis of variance exhibited highly significant differences between the lines for Y p ,Y s and yield components indicating the presence of genetic variation and possible chromosomal localization of the genes controlling the traits investigated. Mean comparison revealed that most of the genes controlling yield and yield components in the rainfed condition are located on chromosomes 4A, 7A, 2D, 5D and 6D. Correlation analysis indicated that the most suitable drought tolerance criteria for screening substitution lines were MP, GMP and STI. Three-dimensional and multivariate biplot display resulted from principal component analysis showed that most of the genes controlling quantitative criteria of drought tolerance are located on chromosomes 7A, 1B, 2D, 4D and 6D.