Drought‐Tolerant Corn Hybrid and Relative Maturity Yield Response to Plant Population and Planting Date

Abstract

Non‐transgenic drought‐tolerant (Tol) corn (Zea mays L.) hybrids may be a tool to help growers manage for precipitation variability during the growing season. However, there is little agronomic research on these hybrids in the eastern U.S. Corn Belt. A field study was conducted from 2012 to 2014 at three Ohio locations (Hoytville, South Charleston, and Wooster) to investigate the yield response of two Tol hybrids compared to two conventional (Con) hybrids of similar relative maturity at five populations (59,000; 74,000; 89,000; 104,000; and 124,000 plants ha−1) planted in May and June. The agronomic optimum plant population (AOPP) to produce maximum yield (AOMY) and the economic optimum plant population (EOPP) to maximize yield (EOMY) were determined using a quadratic‐plus‐plateau model for Tol and Con hybrids as well as maturity group (short‐season and full‐season). Across all locations and hybrids, delayed planting resulted in an increase in AOPP compared to the May planting by 1300 plants ha−1, but EOPP decreased by 3100 plants ha−1. The drought‐tolerant hybrids produced greater AOMY at lower AOPP compared to the conventional hybrids when planted in May, but typically exhibited lower AOMY at lower AOPP when planting was delayed until June. In environments with Con hybrid yield less than 12.2 Mg ha−1, a yield advantage was observed from planting a Tol hybrid. However, above this yield level Con hybrids produced greater yield than Tol hybrids. Short‐season hybrids had a greater AOPP and lower AOMY as compared to full‐season hybrids regardless of plant date.