The stability and variability of maize kernel moisture content at physiological maturity

Maize (Zea mays L.) kernel moisture content at physiological maturity significantly differs among hybrids and is affected by the environment. Nonetheless, 35% was previously reported and is widely accepted as the moisture content at physiological maturity. To verify whether the 35% moisture content could be applied to various hybrids and regions, a multi‐area, multi‐year trial was conducted from 2015 to 2018 in six locations in different maize‐planting regions of China. Time‐series kernel moisture contents and kernel dry weights were investigated for 156 hybrids in total to ascertain the growth pattern of the percentage maximum kernel dry weight as a function of kernel moisture content. The growth patterns were fitted with a tri‐linear model with a plateau, and at the point at which the percentage maximum kernel dry weight first reached its maximum (physiological maturity), the kernel moisture contents were 32% for summer maize, 34% for spring maize, and 38% for Daqing (a special spring maize region). We found that regional variation existed in kernel moisture content at physiological maturity. The regional average moisture content at physiological maturity could thus be used as an indicator to determine physiological maturity for most hybrids in the region. In addition, varietal differences in moisture content could be accounted for when using the regional average value.