Evaluation of CWSI for Three of Corn Cultivars under Drip Irrigation Regimes (The Lands of Khuzestan Northern)

This study was conducted to evaluate the CWSI index in different cultivars of maize under drip irrigation Strategies at Safi Abad Agricultural Research Center, north of Khuzestan province. Irrigation management factors included T100 (100% water requirement), T75 (75% water requirement) and T50 (50% water requirement) were in main plots and maize hybrids including Single Cross 704 (SC), Mobin (M) and Karun (K) were subplots. High and low baseline relationships were estimated for all three cultivars with high accuracy (R2 <0.8) during the growing season. CWSI index varied from 0.01 to 0.46 for different treatments and at different growth stages. The results of statistical analysis showed that the difference of water stress index of maize was not significant between different cultivars but the effect of irrigation management on it was significant at 1% probability level. Accordingly, CWSI values of 0.17, 0.15, and 0.12 were estimated for corn growth and development, middle and end stages, respectively, to determine drip irrigation time using this index. In addition, the results showed that there was a high correlation between CWSI and maize yield and were derived the relationships to estimate yield by using this index. Based on these relationships, Caron hybrid had the highest sensitivityto water stress, with the coefficient or slope of grain and biological yield reduction against water stress were 21% and 47% respectively than were higher from other two cultivars.