Corn Hybrid and Row Spacing Response during Dry Growing Conditions.

There is continued interest in identifying high yielding corn (Zea mays L.) hybrids in narrow rows (<76 cm).  Research evaluated the response of ten phenotypically different hybrids planted at 74,000 and 89,000 seeds/ha in 38- and 76-cm rows from 2011 to 2013 under dry growing conditions in Missouri. Precipitation was up to 35% less (2012) than the 10-year average in the region during this research. Grain yields were 2.7% greater in 38-cm rows compared to 76-cm rows when averaged over seeding rate and hybrid, with four of the 10 hybrids having greater yields in narrower rows.  Drought affected overall yields, though an early maturing hybrid (P0461HR) and a drought tolerant hybrid (P1151AM) yielded more than the others. The higher yielding hybrids showed no yield difference based on row spacing. Corn seeded at 74,000 seeds/ha yielded 25% more in an extremely droughty year (2012) compared to 89,000 seeds/ha, but no yield difference appeared in 2011 and 2013.  Our study indicates that appropriate plant densities and hybrid selection were needed to successfully integrate narrow-row corn into drought prone claypan soils.