Grain Dehydration and Grain-Filling Characteristics of Different Maize Varieties in Heilongjiang

To study the grain-filling and dehydration characteristics of maize and their relationships with yield and screen maize varieties with high yield, high quality, and suitability for mechanical harvesting, this study systematically analyzed the grain-filling and dehydration characteristics of eight early-maturing maize varieties (LK17, BN308, KD15, LK19, G806, G723, and CH6, with DMY3 as the control) planted at the 852 Farm in Heilongjiang Province. The results demonstrated the following: (1) The filling rate of all varieties followed a single-peak curve, peaking at 20–25 days after pollination (DAP); BN308 and CH6 exhibited the highest peak filling rates (1.77 g/(100 kernels·d) and 1.67 g/(100 kernels·d), respectively). (2) Dehydration displayed a clear biphasic pattern. The rapid phase, occurring from 13 to 37 days after pollination, revealed a rate of 2.02 to 2.38 (%/d). This was followed by a slower phase after 37 days, in which the rate declined to 0.75 to 1.31 (%/d). LK19 displayed the fastest dehydration rate (0.89 (%/d)) and the lowest harvest moisture content (19.25%). (3) BN308 achieved the highest yield (13,081.58 kg/ha)-15.5% higher than the control. We clarified that the grain-filling parameters are the core driving factors for high-yield maize. Extending the active grain-filling period and increasing the grain-filling rate can significantly boost the yield, and the active grain-filling period has the greatest impact on the yield. Principal component analysis shows that the starch, fat and protein content, together with the grain-filling parameters, jointly affect the comprehensive quality of the varieties, and balanced selection is required.