Quantifying the effect of low-temperature events on the grain quality formation of wheat

Abstract

Protein and starch are the main components of nutritional quality in wheat grain, which are influenced by temperature. Since few studies have been aimed at quantifying the effect of low temperature on protein and starch formation in wheat, this study was undertaken to employ logistic functions for describing the dynamics of protein and starch accumulation in wheat grain, based on the datasets from two-year temperature-controlled experiments involving different low-temperature intensity, frequency and occurrence time with two genotypes. In general, low temperature had a substantial effect on the grain protein and starch concentrations of wheat and the obvious effect was detected when low temperatures applied at the booting stage. The accumulation of protein and starch decreased with the decreasing temperature and low-temperature duration extension for both Yangmai16 and Xumai30. In addition, the dynamics of protein and starch accumulation under different low-temperature conditions could be described well by logistic functions. The characteristic parameters of maximum accumulation per grain (K), maximum accumulation rate (Rmax) and average accumulation rate (Rmean) in the logistic functions decreased with decreasing temperature and increasing low-temperature duration, and then the active accumulation duration (D) was shortened. Moreover, the sensitivity of the parameters to low temperatures was different. The most sensitive parameters of protein and starch accumulation were K and Rmax for both Yangmai16 and Xumai30, while the least sensitive parameter was D, which indicates that the decreases in protein and starch accumulation under low-temperature treatment were mainly attributed to the maximum protein and starch accumulation per grain and the maximum accumulation rate.