Foliar Application of Potassium Sulfate Partially Alleviates Pre-anthesis Drought-induced Kernel Abortion in Maize

摘要

Reproductive success in cereals is determined primarily by grain setting and grain filling. The kernel abortion in maize during pre-anthesis drought has been widely studied, but the reasons behind this abortion are still largely unknown. The present study investigated the impact of drought stress (control and drought) around pollination and foliar sprays of potassium (K; 0, 1, 2 and 5% K 2 SO 4 ) on leaf K concentrations and yield determinants of maize under greenhouse and field conditions. Results of both experiments revealed that drought stress before pollination strongly reduced the cob fresh weights, number of grains per cob and hence grain yields. While cob length, cob diameter and grain weights were only slightly affected by drought. Potassium concentrations in cob leaves of drought stressed plants were slightly below the critical threshold values. Foliar spray of 2 and 5% K significantly increased the leaf K concentration, number of grains per cob and grain yield in drought treatments of both experiments. Foliar application of K had little or no significant effect on growth and yield determinants of control plants. It is concluded that potassium deficiency could be one factor associated with poor kernel setting under drought stress. Foliar application of 2 and 5% K 2 SO 4 before silking can significantly improve grain number and grain yield in drought- stressed maize.