DIFFERENTIAL RESPONSES OF YIELD AND SELECTED NUTRITIONAL COMPOSITIONS TO DROUGHT STRESS IN SUMMER MAIZE GRAINS

Abstract

Water is a key factor influencing the yield and quality of crops. Thus, a field simulative study was carried out from 2002 to 2003 in order to assess yield and nutritional composition changes in maize (Zea mays L.) grains at three different soil moisture levels: full-watered (FW), moderately stressed (MS), and severely stressed (SS). Our data indicated that SS treatment significantly increased nitrogen (N), calcium (Ca), magnesium (Mg), copper (Cu), and zinc (Zn) contents in maize grains by 11.9%, 27.8%, 11.1%, 18.4%, and 32.9%, respectively, when compared to FW. However, significant decreases (P < 0.05) in starch, phosphorus (P), and potassium (K) contents and yields in maize grains, about 27.9%, 16.5%, 16.7%, and 375.2%, respectively, were seen at SS treatment as compared to those in the FW treatment. In contrast, crude fat content had a different pattern in response to drought stress as compared to most nutritional compositions in maize grains. It generally followed the series MS > FW > SS. These results suggested that although some nutritional compositions in maize grains were positively affected by drought stress, the yields decreased significantly.