Radiation Use Efficiency and Yield in Drought Tolerant Corn in the Texas High Plains.

Corn is the major irrigated crop and anticipated water shortages will challenge the sustainability of corn production in the Texas High Plains. Adoption of newly developed drought tolerant (DT) hybrids may provide some yield benefits in corn under water limited conditions. Radiation use efficiency (RUE) is important for crop yield determination, particularly for high-yielding irrigated corn. However, little information is known in the RUE in the DT hybrids. The objective of this study was to investigate the RUE and grain yield performance of two corn hybrids (one conventional hybrid and one DT hybrid) at two irrigation levels. Field experiments were conducted at the North Plains Research Field, Texas A&M AgriLife research near Etter, TX under a center pivot irrigation system. Treatments consisted of two hybrids (P33D49 and P1151HR) and two irrigation levels (100% and 50%ET requirement). Measurements included biomass, leaf area index (LAI), intercepted photosynthetically active radiation (PAR), harvest index (HI) and grain yield. The 2012 results showed that grain yield did not affect by hybrid at100%  ET (P > 0.05). The RUE of P33D49 and P1151HR were 3.55 and 3.42 g/MJ, respectively. The two hybrids had different final biomass and harvest index (HI) (P < 0.05), and P1151HR had higher HI and lower biomass compared to P33D49.