Heat Stress in Corn: Response of Grain Yield Components to Crop Growth Regulators.

Maize (Zea mays L) grain yield is severely affected by abiotic stresses. The objective of this work was to analyze the response of grain yield components (kernel number and kernel weight) to the combined effect of crop growth regulators associated to ethylene metabolism and heat stress. For this purpose we performed field experiments during two growing seasons. Heat stress was applied between the 10-ligulated leaf stage (V10) and tasseling. Two growth regulators were tested (i) 1-MCP, and (ii) ethephon. Several traits were evaluated: plant growth during the critical period for kernel set, flowering dynamics (anthesis and silking evolution), kernel number per plant, final kernel weight and grain filling evolution, plant grain yield, postsilking leaf senescence and plant nitrogen status by SPAD evolution.