ANALYSIS OF BIOLOGICAL TRAITS CONTRIBUTING TO GRAIN-YIELD OF SHORT-SEASON TO MID-SEASON CORN (ZEA-MAYS-L) HYBRIDS

Biological traits related to grain yield of short- to mid-season corn (Zea mays L.) hybrids were identified, and an approach to determine their relative contribution to grain yield was demonstrated. Nine hybrids with maturity ratings of 2350-2800 corn heat units (CHU) were grown at three sites. Twelve plant-scale traits were measured which reflected development rate, vegetative growth and partitioning to the grain. Analyses indicated significant differences (P less-than-or-equal-to 0.05) in grain yield among hybrids, maturity ratings and sites. Hybrid yield differences were related to hybrid differences in trait values. Traits contributing to yield differences were also selected by a series of multiple linear regressions. The test year was abnormally warm (all sites had more than 2800 CHU) and traits related to the vegetative stature of the plant and the time required to reach that stature were most consistently correlated with yield.