Yield determination of temperate maize hybrids with different end-uses : an ecophysiological analysis

Abstract

Maize (Zea mays L.) production in Argentina changed markedly during the last decade due to the widespread adoption of late sowing dates, expanding its productive area, and diversifying crop end-uses. This study was conducted to assess how the sowing date and nitrogen (N) availability affect grain yield, its physiological determinants (biomass and its partitioning), and numeric components (kernel number and kernel weight) of maize hybrids marketed for different end-uses. Field experiments were conducted in two growing seasons (2019–2020 and 2020–2021) and two sowing dates within each season (early and late) at a site in the main maize-producing region of Argentina. Within each season × sowing date combination, eight commercial maize hybrids (commercialized as grain, dual-purpose, or silage) were tested under two N levels (N0: no N applied; N250: fertilized with 250 kg N ha−1). The greatest grain yield, biomass, kernel number, and harvest index corresponded to the grain hybrids. Dual-purpose hybrids showed an intermediate grain yield, the highest kernel weight, and a more “silage” than “graniferous” behavior. Silage hybrids had improved light interception up to silking + 15 days (R2) but exhibited the lowest grain yield. Differences in end-use steered crop breeding efforts toward different physiological strategies. The improved understanding of the physiological mechanisms underlying the productivity among maize hybrids with varying end-uses will assist in the selection and management of suitable cultivars to be grown under different systems and environmental variations associated with an extended sowing date period.