Seed germination responses of sorghum lines and cultivars under salinity stress conditions.

To evaluate the effect of salinity stress on germination indices of sorghum, this experiment was conducted using a factorial arrangement based on a completely randomized design (CRD) with three replications at Cereal laboratory of College of Agriculture, Shiraz University, Shiraz, Iran in 2015. Treatments included salinity levels (Control (0.5), 3.5, 6.5, 9.5 and 12.5 dS.m-1) and 48 sorghum lines and cultivars.Analysis of variance showed that the effect of salinity was significant on all measured traits at 1% level. In this experiment, increased salinity caused a significant reduction in germination percentage, germination rate, seedling dry weight and vigor index. The highest germination percentage (86%) as well as seedling length (386.2 mm), and vigor index (332.33) was found in KDFGS19 line. Ghalami Herat cultivar had the highest germination rate (12.6/day). Orthogonal comparison for two groups of genotypes indicated that there were significant differences between cultivars and lines for all measured traits (except for seedling dry weight). Lines had higher germination percentage and germination rate compared to cultivars, however, for seedling length and vigor index, cultivars had higher levels than lines. Lines had higher germination percentage and germination rate compared to cultivars, however, for seedling length and vigor index, cultivars had higher level than lines.