Grain Moisture Loss Rate of High-Oil and Standard-Oil Maize Hybrids

High-oil hybrids having the same date of anthesis as normal-oil hybrids are frequently found to have higher moisture content in the grain at harvest time. Field drying rate of maize (Zea mays L.) grain was followed in nine single-cross hybrids differing in percent oil in the kernel and in agronomic traits. The objectives of this study were to determine the duration of the grain filling period (GFP), moisture content at physiological maturity, and grain moisture loss throughout the period after physiological maturity. Hybrids were grown in 1984 in a randomized complete-block design with four replications at Urbana, IL, and Zemun Polje, Yugoslavia. Three ears were harvested from each plot 14 d after pollination (DAP) and at weekly intervals until 70 DAP. Percent moisture in the grain, and 100-kernel weight were measured for each hybrid, harvest date, and location. High-oil hybrids had higher moisture content 70 DAP than did normal-oil hybrids. Differences in kernel moisture percent among oil groups at the beginning of GFP were not significant at Zemun Polje, but were significant at Urbana. At the time of approximate physiological maturity the 7% oil group had significantly lower moisture percent in the grain than did the normal- and 9% oil hybrids at both locations, and had significantly lower moisture percent in the grain than the 9% oil hybrids at Zemnn Polje only. There were no significant differences in rate of kernel water loss among oil groups throughout the GFP. However, normal-oil hybrids were faster drying than 7 and 9% oil hybrids after physiological maturity. Differences in the drying down rate between the 7 and 9% oil groups were not significant at one (Urbana) of the two locations. Contribution of the Maize Res. Inst., “Zemun Polje”, 11081 Zemun, Yugoslavia, and the Dep. of Agronomy, Univ. of Illinois, Urbana, IL 61801.