Mixing trait-based corn (Zea mays L.) cultivars increases yield through pollination synchronization and increased cross-fertilization

Abstract

Abiotic stress such as high temperature at flowering is one of many conditions reducing yield of corn (Zea mays L.). Mixing corn cultivars with diverse functional traits increases within-crop diversity and provides a potential means of mitigating yield losses under stress conditions. We conducted a three-year field study to investigate the effects of cultivar mixtures on kernel setting rate, pollen sources, and yield. This study consisted of six treatments, including two high temperature-tolerant (HTT) monocrops of WK702 and DH701, two high temperature-sensitive (HTS) monocrops of DH605 and DH662, and two HTT–HTS mixtures of WK702-DH605 and DH701-DH662. The anthesis–silking interval (ASI) was 0.9–1.6 days shorter in mixtures than in monocrops. Kernel setting rate was increased in mixtures (86.4%–88.7%) compared with those in monocrops (74.7%–84.1%) as a result of synchrony and complementarity of pollination. Grain yields of the HTT–HTS mixtures increased by 13.3%–18.7%, equivalent to 1169 to 1605 kg ha−1, in comparison with HTS corn monocrops. The results of SSR markers showed that cross-fertilization percentage in corn cultivar mixtures ranged from 29.3% to 47.8%, partially explaining yield improvement. Land equivalent ratio (LER) was 1.12 for corn mixtures and the partial land equivalent ratio (e.g., > 0.5) showed the complementary benefits in corn mixtures. The results indicated that mixing corn cultivars with diverse flowering and drought-tolerance traits increased yields via pollination synchrony.