Effect of water availability and genetic diversity on flowering phenology, synchrony, and reproductive investment in maize

Abstract

Crop yield of monoecious species like maize (Zea mays) relies on simultaneous flowering of male and female inflorescences to ensure pollination. Yet productivity may be reduced if environmental conditions reduce floral synchrony or if plants within a field do not overlap sufficiently in flowering periods. We experimentally manipulated water availability and measured its effect on flowering, including the anthesis-silking interval (ASI) and crop yield components in open-pollinated (OP) and hybrid corn cultivars. Although watering treatments did not affect traits, we did detected cultivar-specific phenological and yield responses. Hybrid plants were earlier to silk than OP plants, which tasseled for longer, had a longer ASI, and lower yield components. The less diverse hybrids also expressed less variation in ASI. We suspect other methods for reducing moisture in the field, including earlier moisture removal, might have better elicited a biological response in maize. Nevertheless, because shorter ASI is genetically correlated with increased drought tolerance, we predict this hybrid may be more resilient than the OP under more extreme drought scenarios. Consideration for how genetic diversity found in OP varieties and crop landraces may respond to variation in moisture availability apparent with climate change may be warranted.