| dc.description.abstract | A two-year (2011 and 2012) study was conducted at the Texas A&M AgriLife Research Farm near College Station, Texas, to examine the effects of planting date and hybrid maturity on moisture stress in corn (Zea mays L.). The objective of this research was to determine the interactive effects of these factors on corn physiological processes, development, growth and yield in southcentral Texas. Treatments consisted of two irrigation strategies (dryland and irrigated), three planting dates (25-Feb, 10-Mar, and 25-Mar), and four hybrid relative maturities (117 day, 111 day, 95 day, and 83 day). Plants were evaluated at three different growth stages (R1, R3 and R5), with several physiological parameters measured, including: photosynthetic activity, chlorophyll fluorescence, leaf temperature, and yield. Photosynthetic activity was the rate of stored carbon assimilate measured with a LI-COR 6400. Chlorophyll fluorescence was the quantum efficiency of photosystem II measured with a PAM-2100. Leaf temperature was measured with SmartCrop infrared canopy temperature sensors and data was represented as canopy temperature less ambient air temperature (canopy temperature depression). Significant differences due to treatment occurred for all the above parameters. Measurements taken at the R1 growth stage provided little insight relative to plant stress. Canopy temperature depression was more indicative of stress than actual leaf temperature. Irrigation provided greater yield, height, and photosynthetic activity. In general, later planting and longer maturing hybrids increased grain yield. | en |
