Effects of Water Deficit at Tasseling on Proline and Abscisic Acid Levels and Yield of Corn

Abstract

Water stress affects a number of physiological processes which consequently affect crop yield. The objective of this study was to determine the effects of water stress on levels of proline and ABA and yield of 2 corn varieties; Ki3, a purported drought-sensitive variety, and Ki11, a purported drought-tolerant one. Plants were exposed to water stress at tassel initiation and at anthesis until wilting appeared and then rewatered until recovered. Leaf samples were collected at wilting and at recovery for proline and ABA analyses using spectrophotometric technique and gas chromatography, respectively, compared to control plants. It was found that water stress at both tassel initiation and anthesis caused an increase in proline and ABA levels in both corn varieties. The increase was greater in Ki3 than in Ki11. When plants were rewatered, both proline and ABA levels decreased to the control level. Water stress at both stages decreased number of seeds per ear and seed weight in both corn varieties which consequently decreased grain yield per plant but the effect was more evident in Ki3 than in Ki11. Water stress at tassel initiation showed greater influence on proline and ABA levels and yield than that at anthesis. Moreover, it was found that proline and ABA levels accumulated under water stress conditions were negatively correlated with corn yield.