The Effect of Planting Date and Irrigation Regimes on Yield and Chlorophyll Content, Osmolytes and Antioxidant Enzymes in Sweet Corn (Zea Mays L. var saccarata)

Abstract

The occurrence of drought stress in most areas of Iran with limited water reserves, the need to use agricultural techniques and adaptation measures with the aim of helping crop producers to choose the appropriate planting date and optimal use of irrigation water to increase corn production is necessary. In order to investigate the yield, chlorophyll content, osmolytes and the activity of antioxidant enzymes in sweet corn (cv. Amylopop) in response to drought stress and delay in planting, an experiment was conducted as split plots based on a randomized complete block design with three replications during two growing seasons (2018 and 2019) at Razavi Khorasan Province, Iran. The treatments included the irrigation as the main factor in three levels [100% water requirement, 80% water requirement (mild stress), 60% water requirement (severe stress)] and planting date as a sub-plots in three levels (16 May, 26 May and 5 June). The findings showed that grain yield and leaf chlorophyll content decreased by 62% and 40% by delay in planting and increased drought stress caused by low irrigation regime, respectively, compared to the control (no stress and timely cultivation), and also, glycine betaine, proline, soluble sugars and antioxidant enzymes contents increased. Therefore, according to the climatic conditions of the Mashhad region, water loss through surface evaporation is much less at the beginning of the growing season, so it is necessary to choose the well-timed planting date and not to use a low irrigation strategy to achieve the maximum grain yield.