Effects of exogenous abscisic acid on kernel water content of Different Maize Varieties during grain filling

Abstract

The kernel water content during harvest is the key factor affecting mechanized grain harvest application in China. The kernel water content during corn harvest is affected by the grain filling rate, the water content at physiological maturity, and the dehydration rate after physiological maturity. In this study, two maize varieties with differing dehydration rates: DK517 (fast dehydration) and ZD1002 (slow dehydration), were treated with exogenous ABA after heading and powdering. The effect on grain filling, water content at harvest, yield, and key differential protein expression and metabolic pathways were then determined. Yield was significantly lower in DK517 than ZD1002 after application of exogenous ABA. ABA also had a greater effect on the grain filling rate in DK517, while the timing of maximum grain filling occurred 5.72 days later than that of the control and the active grain filling period was 15.49 days longer. At 60 d after pollination, the grain water content was 23.55% in DK517 and 30.42% in ZD1002, 8.88% higher and 0.26% lower than that of the control, respectively. In DK517, a total of 861 differentially expressed proteins were screened after exogenous ABA application, and of these, 246 were up-regulated and 615 were down-regulated. In ZD1002, 118 proteins were identified, of which 56 were up-regulated and 62 were down-regulated. The findings suggest that application of exogenous ABA has differing effects on the grain filling characteristics of different maize varieties, with a greater overall effect on varieties such as DK517 with a faster dehydration rate.