Investigating sweet corn (Zea mays L.) yield determining traits under normal irrigation and water deficit stress, using multivariate statistical methods

In order to study the effect of drought stress on morphological traits, yield and yield components of sweet corn, a split plot factorial experiment based on RCBD was conducted with four replications at the experimental field of the agricultural and natural resources research center of Khorasan-Razavi (Tourogh station of Mashhad) in 2010,. Responses of three sweet corn hybrids (including two sweet and one super sweet hybrid) to three different water levels in two planting methods, were studied. Water levels [I1: 100%-(full irrigation or control), I2: 80% (moderate stress), and I3: 60% (severe stress) of field capacity] were assigned as main plots, while in sub plots, cultivar (Ksc403, Merit and Absizhen) and planting method (planting on the ridges or on the ditches) were combined as a factorial arrangement. Crop yield and 17 effective characteristics of sweet corn plants were studied in this study. Analysis of variance showed that there were significant differences between different hybrids in terms of evaluated traits. Drought stress also significantly affected all measured characteristics. Correlation analysis showed that in normal irrigation and drought stress conditions, ear length, leaves number above main ear and seed row per ear showed the greatest positive correlation with kernel yield. Stepwise regression analysis and principal component analysis showed that, 1000- seed weight, anthesis-silking duration (ASI) and kernel number in ear were the most limiting traits in sweet corn production.