Haplotype Analysis and Gene Pyramiding for Pre-Harvest Sprouting Resistance in White-Grain Wheat

The Huanghuai winter wheat region, China's primary wheat-producing area, predominantly cultivates white-grained wheat. Pre-harvest sprouting (PHS) significantly impacts yield and quality, making the breeding of PHS-resistant varieties crucial for ensuring China's wheat production security. This study evaluated the PHS rate of 344 white-grained wheat varieties over two consecutive growing seasons (2022/2023 and 2023/2024). Furthermore, it analyzed the effects of allelic variations and their combinations in six genes (Tamyb10, TaDFR, TaMKK3-A, TaGASR34, Tasdr, and TaMFT) on PHS resistance. Results revealed average PHS rates of 66.1% and 64.4% for the two growing seasons, with coefficients of variation of 39.1% and 40.2%, respectively, and a narrow-sense heritability of 0.72. These findings indicate substantial genetic variation and relatively high genetic stability within the tested materials. Among the six molecular markers examined, the superior haplotype GS34-7Bb exhibited the lowest average PHS rate (41.9%) over two growing seasons, demonstrating the strongest PHS resistance. Analysis of different haplotype combinations identified two advantageous genotypes for PHS resistance in white-grained wheat: TaMKK3-Ab + GS34-7Bb + Tasdr-2Aa + TaMFT-A1b (average PHS rate: 20.8%) and TaMKK3-Ab + GS34-7Bb + Tasdr-2Ab + TaMFT-A1b (average PHS rate: 34.2%). Notably, the distribution frequency of superior haplotypes of PHS-related genes and these two advantageous haplotype combinations showed varying degrees of decline over time.