Evaluation and Selection of Bread Wheat Genotypes Using Physiological Traits and Drought Tolerance Indices

Seventeen genotypes of bread wheat along with three check cultivars were evaluated for some important traits related to drought tolerance, including germination stress index (GSI), rootlet number and length, coleoptile length, proline content of flag leaf, cell membrane stability, relative water content (RWC), excised leaf water content, chlorophyll a and b content, stress tolerance indices (STI and TOL) and other morphological traits under field and laboratory conditions. The experiments were conducted in RCBD with three replications in Dryland Agricultural Research Institute, Sararood Station, Kermanshah, in 2003-04 and 2004-05 cropping seasons. At the seedling stage, the genotypes Bow"S"/Gen//Shahi, Ghods *3/Kavvko //Ghods *3/Ka z/ Kavko, Gene Bank-914, 4848 Mashhad/Tui "S" IRW92 1D6 and Roshan/3/F12. 71/Coc//Gno79. performed better than the others. However, in field conditions based on relative water content, proline content, cell membrane stability, chlorophyll content under stress condition, and stress tolerance index, four genotypes were selected. Simple correlation coefficients revealed that STI had high and positive significant relation with grain yield, different traits in germination stage, and germination stress index, while showed negative and significant relation with cell membrane damage. Based on the overall results, four superior genotypes were selected for further stage of selection. The genotype Ghods*3/Kavvko//Ghods*3/Kaz/Kavko had most of the traits effective on drought tolerance as well as higher yield in both years