Relative drought tolerance of various desert saltgrass (Distichlis spicata) genotypes

Desertification of arable lands due to urbanization, global warming, and low rainfall mandates water conservation and using low quality waters for irrigation. Using low quality irrigation water imposes more stress on plants which are already under stress in these regions. Thus, there is an urgent need for finding drought tolerant plants to survive under water deficit conditions. The objectives of this study were to find the most drought tolerant saltgrass genotypes for use in arid regions, where limited water supplies coupled with saline soils result in drought/salinity stresses, for use in urban landscapes. Various saltgrass genotypes were studied to evaluate their growth responses under progressive drought stress. Drought stress was imposed via a competitive dry down technique. Drought tolerance was ascertained by relative shoot dry weight and green leaf area. Though all the grasses showed a high level of drought tolerance, there was a wide range of variations observed in their stress tolerance levels. Overall, the results (clipping dry weights and the percent of the visual green cover) showed that the A138 and A137 (Arizona accessions) were the most drought tolerant accessions and the C10 and C66 (Colorado accessions) were the least tolerant ones. In regards to drought tolerance, the rest of the grass accessions were between these two groups. Most of the saltgrass accessions were more tolerant to drought stress than the bermudagrass. Bermudagrass reached full dormancy and/or necrosis stage before most of the saltgrass accessions.