QUALITY FORMATION AND PHYSIOLOGICAL REGULATIONIN WHEAT GRAINS

摘要

To understand physiological characteristics of grain quality formation and explore regulation techniques for improving quality properties of wheat, we have conducted a series of studies under field environments and controlled cultivation conditions inthe past two years. In the first study, 40 representative cultivars from east China region were grown in two different locations, Nanjing and Xuzhou, to assess genotypic differences in grain quality and genotype-environment interaction. A total of 12 grain quality traits were measured. The results showed that all the above grain quality traits significantly varied with genotypes. Most grain quality traits are affected by environment, except for gluten index, amylose and total starch contents, while alltraits are extremely affected by genotype-environment interaction. According to the close relationships among grain quality traits, general regression equations for bread baking quality and biscuit baking quality prediction and evaluation were developed.During the entire period of grain filling, the protein concentrations in grains of high protein content genotypes were higher than in low protein genotypes. In high protein genotypes, protein decomposition in sheathes and culms contributed more to grainprotein synthesis, while in low protein genotypes, pre-stored carbohydrates in leaves, sheathes and culms contributed more to grain starch accumulation. To assess the regulation pathways of grain quality formation, different carbon (sucrose) and nitrogen(glutamic acid) concentrations were supplied to change the balance between carbon and nitrogen. Two methods were used in this study, liquid culture of ears and injection of substrates into the peduncles. From the preliminary experiments, a concentrationof 40 g/L sucrose and 3 g/L glutamic acid is found to favor protein accumulation in grains.