Evaluation of the Effects of Deficit Irrigation on Yield, Yield Components, Proline Content, and Water Productivity of Four Seed Corn Cultivars in Gorgan, Iran

In order to evaluate the effects of deficit irrigation on the yield and water productivity of grain corn in the climatic conditions of Gorgan,an experiment was conducted using split plots in the form of a randomized complete block design in three replicates at the Araghi Mahaleh Research Station of Gorgan, in 2021. The main factor was irrigation treatments at four levels (100% (control), 75%, 50%, and 25% of corn water requirement) and was done based on soil sampling for moisture determination and use of drip irrigation by tape, and the secondary factor consisted of four corn varieties (SC703, SC704, ZP548, BK50). The results of the analysis of variance showed that the effect of irrigation factor was significant (p< 1%) on the examined traits, except the number of rows in the ear. The effect of cultivars on all traits (number of rows per ear, days until earing, plant height, number of seeds per row, weight of 1000 seeds, length of ear, dry weight of stem and leaves, dry weight of cob wood, grain yield, yield, water productivity, and leaf proline) was also significant (p< 1%). Additionally, interaction of deficit-irrigation and cultivars on the traits of the number of rows of seeds, weight of 1000 seeds and seed yield was significant. Comparing the averages showed that the highest seed yield (7722 kg/ha) was observed in the control treatment and the seed yield of the 75%, 50% and 25% treatments compared to the control was 6.8%, 52.4%, and 82% less, respectively. ZP548 hybrid had the highest seed yield (5576 kg/ha) and the highest amount of proline was obtained from the 25% water demand treatment (9.91 μmol/g). The highest water productivity was observed in the 75% treatment (1.07 kg/m3). Considering the large volume of water saving (2258 m3/ha) in this treatment, irrigation is recommended based on 75% of water requirement and cultivation of ZP548 variety in Gorgan region.