Ranking Forage Sorghum Lines (Sorghum bicolor L.) to Drought Stress Basis Seedling Growth in Laboratory Condition

In order to identification of tolerant lines of sorghum to drought stress, an experiment was conducted at Seed Laboratory, Islamic Azad University, and Shoushtar Branch, Iran in 2013. This investigation was performed as factorial experiment under Completely Randomized Design (CRD) with three replications. First factor had fifteen levels of promising forage sorghum lines and the second factor had five salinity levels (0, -3, -6, -9 and -12 bar) of PEG 6000. Analysis of variance showed significant effects of line, salinity and interaction for all of traits. Results indicated that germination percentage (57.03%), length of radicle (75.86%), length of plumule (80.51%), seed vigour index (86.90%) and fresh weight of seedling (46.68%) were decreased by decrease in osmotic potential (-12 bar) whereas the best performance was obtained from seedlings germinated in disstilled water (control treatment). The mean germination time (76.62%) increased with decrease in the osmotic potential in PEG 6000 solution (-12 bar With attention to lines ranking basis studied traits, lines KFS9 and KFS10 as the tolerant to drought to own specified the best score and line KFS1 had the lowest score to drought tolerance.