Effect of Abiotic Stress on Irrigated Maize Forage Yield as Compared to Sorghum

A study was conducted in Sudan (Africa) during the summer and winter seasons (2013 – 2014) at two locations: Shambat (normal soils) and Soba (salt affected soils). Nine maize (Zeamays L.) and sorghum (Sorghum bicolor (L.) Moench) cultivars were studied under two watering regimes arranged in split plot experiment in randomized complete block design. The eight test-environments created by the combination of locations, seasons and watering regimes were used to investigate the effect of salt, water and heat stresses on forage yield and some related traits. The results showed that separate and combined stress factors significantly reduced forage yield. The greatest reduction in dry matter yield caused by one factor was shown by salt stress (29.6%) and the least reduction was caused by heat stress (3.9%). Water stress coupled with either heat or salt stress caused the greater reduction in yield (37.0%-43.3%) than the combination of the other factors. Full stress caused 53.8% yield reduction. Days to tasseling was significantly reduced by heat stress whereas water and salt stress showed no significant effect on tasseling duration. Full stress caused the greatest effect on days to tasseling. Plant height and stem diameter were significantly reduced by salt and water stress. Two hybrids kept top rank in yield through most abiotic stress levels showing resilience to unfavorable environments. All maize genotypes significantly outyielded the sorghum check under no heat stress (winter sowing) regardless the effect of salt and water stresses while the opposite is true under the heat stress (summer sowing). It was concluded that salt and water stress are the major abiotic stresses limiting forage maize production. Maize tolerate better reduction in temperature than dose sorghum while the latter tolerate better salt and water stresses than dose maize. Forage maize could be competitively grown during summer if water and salt stresses are avoided