Variability in Salt Tolerance of 10 Sorghum Genotypes

Sorghum bicolor (L.) Moench (sorghum) is one of most promising bioethanol crops because it is well adapted to semi-arid region where soil salinity is high and groundwater with high salinity is the major water source. Large variation in salt tolerance exists among sorghum genotypes. To provide additional information about such variation, the relative salt tolerance of 10 sorghum genotypes, 1790E, BTx643, Desert Maize, Macia, Schrock, Shallu, Tx2783, Tx430, Tx7078, and Wheatland was evaluated in a greenhouse study by irrigating plants with nutrient solution at electrical conductivity (EC) of 1.3 dS·m^-1 (control) or saline solution at EC of 5.0 or 10.0 dS·m^-1 for 30 days. Saline solution at EC of 5.0 and 10.0 dS·m^-1 had similar influences on shoot dry weight (DW) of all sorghum genotypes except for Tx2783. Compared to the control, the saline solution at EC of 5.0 and 10.0 dS·m^-1 reduced shoot DW by 38% and 47%, respectively; and increased the number of tillers by 112.8% and 116.0%. Foliar salt damage was observed on all salt-treated sorghum genotypes except for Shallu, which had the lowest shoot DW reduction and best visual score. In conclusion, Shallu was the most tolerant genotype, Desert Maize, BTx643, 1790E, Tx2783, Wheatland, Tx430, and Tx7078 had intermediate tolerance, and Macia and Schrock were the least tolerant genotypes.