Molecular characterization of four sorghum cultivars and their ability to germinate under heat, drought and salinity stress

In this work, the ability of four different sorghum cultivars (cv.), 'Dorado' (D), 'Giza 15' (G15), 'Shandaweel 305' (Sh305) and 'Shandaweel 306' (Sh306), to germinate under three abiotic stresses (heat, drought or salinity) was investi-gated. Although the decrease in seed germination and seedling growth was directly proportional to the increase in stress intensity, the influence of each stress agent was cultivar-dependent. Both cv. G15 and Sh305 tolerated the applied abiotic stresses better than cv. D and Sh306, and the former showed higher percentages of seed germination and seedling growth. In comparison to control, relative extremism in temperature, drought or salinity led to progressive increase of antioxidant enzyme activities (SOD, CAT, APX and POX). The total operating units (Unit g(-1) FW) of the studied antioxidant enzymes of the stress tolerant cultivars were higher than those of the stress sensitive ones. The study shows that both RAPD and ISSR techniques could be used to characterize the genome of sorghum cultivars, i.e., the two dendrograms obtained by those methods proved to be very similar. The dendrograms did not reflect the ability of the tested cultivars to germinate under the studied stress conditions as one of the two closely related cultivars (cv. Sh305) proved to be tolerant, the other one (cv. Sh306) sensitive to abiotic stresses.