Response of maize hybrids under limited irrigation capacities: Yield and yield components

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AbstractGrain yield of maize (Zea mays L.) in the semiarid Texas High Plains (THP) is greatly reduced when irrigation cannot meet peak water requirements. Drought‐tolerant hybrids may mitigate yield losses resulting from water deficits. We examined the effect of irrigation capacity (8.47 and 4.23 mm d–1) and planting rates (74,000 and 95,000 seeds ha–1) during three growing seasons (2016–2018) on grain yield and yield components of three maize hybrids, two of which were considered drought tolerant. Crop water deficits at the low irrigation level usually extended temporally from seventh leaf collar to dough stage. Mean grain yields varied from 5.2 Mg ha–1 under the low irrigation level to 19.9 Mg ha–1 at the high irrigation level. Hybrid did not influence grain yield and aboveground biomass in all 3 yr. Although kernel number and kernel mass were significantly influenced by hybrid across all years, this did not result in grain yield differences because greater kernel mass compensated for reduced kernel number. Harvest index did not significantly differ between conventional and drought‐tolerant hybrids. In 2016, grain yield was significantly influenced by plant density only at the low irrigation level, with 44% greater yields at the low plant density. For the patterns and level of water stress observed during these three growing seasons, the three hybrids performed similarly. Besides using hybrids well adapted to the region, mitigation of yield reductions under limited irrigation capacities in the THP can be achieved by concentrating irrigation on less land area and optimizing planting rates.