Impacts of Reproductive Stage Water-Deficit Stress and Weed Competition on the Productivity of Maize (Zea mays L.) and Grain Sorghum (Sorghum bicolor L. Moench)

Due to the growing risk for water shortage during the summer season, grain sorghum has become a popular alternative to maize in most drought-prone areas of Hungary. A three-factorial model experiment was carried out between 28 May 2024 and 11 September 2024 in Keszthely (Hungary) in order to compare the responses of P8834 maize hybrid and RTG Huggo grain sorghum hybrid to weed infestation and different levels of reproductive stage water-deficit stress (50% and 30% water supply relative to the individual controls' water consumption). The treatments were set in a Thornthwaite-Mather type compensation evapotranspirometer, so water consumption could be controlled and monitored. Based on the results, weed interference affected all phenological and yield attributes of both species negatively, but the interaction of weed infestation and water treatment did not enhance relative grain yield loss neither in maize (p = 0.851) nor in grain sorghum (p = 0.28). Since temperature conditions during the reproductive stage were more favourable for grain sorghum, the general yield surplus for sorghum over maize (p < 0.001) was attributed to sorghum's better tolerance to temperature stress. The results also revealed that up to 50% water stress level, the yield stability and water use efficiency of grain sorghum were also better than those of maize, both in weed-free and weed-infested treatments. In conclusion, grain sorghum should be recommended as an alternative to maize in areas that are affected by extreme heat events and moderate water scarcity.