Effect of Waterlogging on Quality of Maize Kernels at Filling Stage

  Objective  Effects of waterlogging on quality of maize kernels at filling stage were studied to decipher the mechanism and for breeding selection.

  Method  Two backbone maize inbred lines in Guangxi, 88M-1-8 and Xian 21A, were subjected to normal water irrigation (CK) or artificial flooding treatments (W) after pollination. The experiment lasted 14d or 18d with a total of 4 variables, i.e., CK-14, CK-18, W-14, and W-18. Contents of soluble protein, soluble sugar, starch, sucrose, and abscisic acid (ABA) as well as activities of sucrose synthetase (SS-I in decomposition direction) and granule-bound starch synthase (GBSS) of the kernels were measured. Effect of waterlogging on maize quality at filling stage was evaluated using the principal component analysis and membership function method.

  Result   Under W-14, the contents of protein, starch, and ABA and the activities of SS-I and GBSS in 88M-1-8 were significantly higher than those in Xian 21A, so were the soluble sugar, starch, ABA, and GBSS in 88M-1-8 under W-18. As the waterlogging prolonged, the soluble protein, starch, sucrose, SS-I, and GBSS in both inbred lines raised significantly. The protein, starch, ABA, and SS-I in 88M-1-8 increased more significantly, and the soluble sugar, sucrose and GBSS in Xian 21A more significantly in W-14 than CK-14. Furthermore, compared with CK-18, W-18 induced more significant increases on the soluble sugar and ABA in 88M-1-8, and the protein, starch, sucrose, SS-I, and GBSS in Xian 21A. Evaluated by the principal component analysis and membership function method on various kernel quality indicators, the tolerance of the two species to flooding were 88M-1-8 under W-14＞88M-1-8 under W-18＞Xian 21A under W-14＞Xian 21A under W-18.

  Conclusion   Artificially flooding the maize plants raised the soluble protein, soluble sugar, starch, sucrose, SS-I, and GBSS in kernels over regular irrigation. 88M-1-8 and Xian 21A differed in responses to the stress. Waterlogging-tolerant 88M-1-8 was significantly higher in the GBSS activity and ABA and starch contents than Xian 21A. Nonetheless, prolonged waterlogging reduced the stress tolerance of either cultivar.