Genetics and Grain Filling Effects on Starch Properties in Wheat

The physicochemical properties of wheat (Triticum aestivum L.) determine its application. This study aims to investigate the genetic patterns and heterosis performance of physicochemical properties of wheat starch, using the variety Xinong99 and two filling-deficient mutants, dwarf wrinkle grain (dwg) and dwarf narrow grain (dng), obtained by EMS mutagenesis, as well as their backcross F1 generations, to systematically compare differences in starch structure, pasting characteristics, and thermal properties. The results showed that the mutants exhibited higher relative crystallinity, significantly reduced starch content and gelatinization temperature, while the gelatinization enthalpy and breakdown viscosity were significantly increased. Some F1 generation germplasm exhibited transgressive heterosis in viscosity characteristics; for example, the dng F1 had peak viscosity (4669 cP) and breakdown viscosity (2618 cP) higher than the parents, but its gelatinization enthalpy (2.29 J/g) was significantly lower than both parents. Furthermore, the dwg mutant starch granules had a more compact growth ring structure and showed higher resistance to digestion potential. This study systematically reveals the mechanisms of trait formation in mutants and hybrid offspring from the dimensions of starch structure–function–genetics, providing a theoretical basis and germplasm foundation for improving wheat starch quality through molecular design breeding.