Response of forage sorghum cultivars to different water availability

To explore the effects of varied irrigation regimes on different sorghum [Sorghum bicolor (L.) Moench] cultivars, a split-plot experiment adhering to a randomized complete block design with three replications was conducted in 2016 across the Khaveh and Varamin regions. The experimental treatments encompassed irrigation levels as the primary factor and four different sorghum cultivars as the secondary factor. Cultivars exhibiting larger leaf areas were associated with higher chlorophyll content, which enhanced biomass production and the quality of sorghum products. Notable variability in leaf area and crude fiber content was observed across irrigation regimes and cultivars, with 2121 cm2 to 7153 cm2 and 40.4% to 50.7%, respectively. Plant height, total dry weight, and water use efficiency were markedly higher under well-irrigated conditions than those under moderate and severe water deficit conditions. Specifically, the Pegah cultivar displayed the highest leaf area in the Varamin region, measuring 4612 cm2 and 5911 cm2, whereas the Thin Stem cultivar exhibited the lowest leaf area at both locations. Our findings suggest that the Pegah cultivar maintained a high leaf area without reducing total dry weight, indicating its stability across different environments. Therefore, to produce sorghums in similar climatic conditions, full irrigation is recommended. These results underscore the significance of ongoing research and breeding initiatives to leverage genetic diversity and improve sorghum cultivars.