Regional multi-environment analysis of corn productivity and yield stability as impacted by hybrid maturity

Corn (Zea mays L.) hybrid maturity selection can help maximize productivity, yield stability, and optimize the use of available resources such as water, solar radiation, and nutrients. We explored yield differences by hybrid maturity with long term data from corn hybrid performance tests conducted between 2005 and 2017 in three U.S. states with variable area under irrigation: Arkansas (AR; 50 environments, 100% irrigated), Nebraska (NE; 22 environments, 59% irrigated), and Kentucky (KY; 54 environments, all rainfed). Stability-analysis techniques and probability functions were used to test the effect of Corn Relative Maturity (CRM) on yield and yield stability. Average yields increased per unit increase in CRM group by 51 kg ha⁻¹ CRM⁻¹ in AR and 122 kg ha⁻¹ CRM⁻¹ in NE. Thus, hybrids maturity recommendations to maximize yield were the latest CRM groups included in Corn Performance Tests in AR and NE (CRM 118−120 and 115−118, respectively). In contrast, the yield response to CRM group showed a quadratic relationship in KY, and selecting CRM groups later than 109–114 would reduce yield stability and likely delay harvest without providing a significant yield advantage. Full-season hybrids in AR and NE also showed the greatest responsiveness to environments of increasing average productivity, unlike in KY where all CRM groups showed similar responses. Different results observed across the three states may be partially attributed to different percentage of irrigated sites, with the implication that optimum hybrid maturity recommendations may need to be redefined depending on water availability.