Jim Gaffney, Jeff Schussler, Carlos Löffler, Weiguo Cai, Steve Paszkiewicz, Carlos Messina, Jeremy Groeteke, Joe Keaschall and Mark Cooper

CROP SCIENCE, June 2015, Vol. 55 No. 4, p. 1608-1618

Abstract

Maize (Zea mays L.) is among the most important grains contributing to global food security. Eighty years of genetic gain for yield of maize under both favorable and unfavorable stress-prone drought conditions have been documented for the US Corn Belt, yet maize remains vulnerable to drought conditions, especially at the critical developmental stage of flowering. Optimum AQUAmax (Dupont Pioneer) maize hybrids were developed for increased grain yield under drought and favorable conditions in the US Corn Belt. Following the initial commercial launch in 2011, a large on-farm data set has been accumulated (10,731 locations) comparing a large sample of the AQUAmax hybrids (78 hybrids) to a large sample of industry-leading hybrids (4287 hybrids) used by growers throughout the US Corn Belt. Following 3 yr (2011–2013) of on-farm industry-scale testing, the AQUAmax hybrids were on average 6.5% higher yielding under water-limited conditions (2006 locations) and 1.9% higher yielding under favorable growing conditions (8725 locations). In a complementary study, 3 yr (2010–2012) of hybrid-by-management-by-environment evaluation under water-limited conditions (14 locations) indicated that the AQUAmax hybrids had greater yield at higher plant populations when compared to non-AQUAmax hybrids. The combined results from research (2008–2010) and on-farm (2011–2013) testing throughout the US Corn Belt over the 6-yr period from 2008 to 2013 indicate that the AQUAmax hybrids offer farmers greater yield stability under water-limited conditions with no yield penalty when the water limitations are relieved and growing conditions are favorable.

Figure 2: Graphical summary of the incidence of AQUAmax (Dupont Pioneer) and non-AQUAmax hybrids in individual experiments by state within year for the three data sets reported in the paper: small-plot, population density, and on-farm. The vertical dimension represents the individual hybrids in the same order as they are listed in Supplemental Table S1. The horizontal dimension represents an ordering of states within year. The vertical dashed line indicates the transition from small-plot research experiments to on-farm strip testing. The horizontal dashed line indicates the transition from the AQUAmax to non-AQUAmax hybrids