ارزیابی تحمل به تنش رطوبتی آخر فصل در 20 لاین امید بخش جو

In order to evaluate the effect of terminal moisture stress on 20 barley promising lines (Hordeum vulgare) and for determination of their relative tolerance, an experiment was conducted based on randomized complete blocks design with three replications in growing season of 2010-2011. In this research some old indices such as, stress susceptibility index (SSI), tolerance index (TOL), mean product (MP), geometric mean product (GMP), stress tolerance index (STI), relative drought index (RDI) and two new indices namely, stress susceptibility percentage index (SSPI) and stress non-stress productivity index (SNPI) were used. The lines differences were significant for yield under both non-stress and stress conditions. The results also showed that the indices of MP, GMP, STI and SNPI were significantly correlated to Yp and Ys. Therefore, the above-mentioned indices are the best ones for selection of lines with high yield under non- stress and moisture stress conditions. The results of principal component analysis indicated that the lines number of 10, 4 and 6 were the most resistant lines and the lines number of 13, 16 and 17 were the most sensitive lines. In addition, bi-plot results indicated that MP, GMP, STI and SNPI indices had the most alignment with the yield of lines under stress conditions (Ys). Therefore, theses indices are the best ones for resistant lines with high yield under moisture stress conditions. In cluster analysis, examined lines were generally grouped in two clusters, so that susceptible and relatively susceptible lines underwent in the first cluster and resistant and relatively resistant lines underwent in the second cluster. Finally, SNPI, STI, GMP and MP indices were the best ones and the line of number 10, 4 and 6 were the most resistant lines, respectively.