Breeding Utilization of the White-Grained Pre-Harvest Sprouting-Resistant Wheat Landrace Tuotuomai Through Marker-Assisted Selection

Improving pre-harvest sprouting (PHS) resistance in white-grained wheat is challenging because reduced grain pigmentation is often associated with weaker seed dormancy. Here, we evaluated the breeding value of the white-grained, PHS-resistant landrace Tuotuomai (TTM) and developed a molecular marker for tracking TTM-derived material during breeding. Based on phenotypic segregation and sequence polymorphism analysis, a KASP marker targeting a polymorphic site in the TaMyb10-D1 region was developed. The marker co-segregated with white grain color in the TTM × CS population, and the TTM-type marker genotype occurred more frequently in low-germination-percentage (GP) than in high-GP groups of the TTM × AK58 segregating populations. The marker was subsequently combined with phenotypic selection in pedigree and multi-parent breeding schemes. The derived white-grained line SMBK3 had a GP of 29.33%, compared with 98.67% for AK58, and showed reduced plant height and increased thousand-kernel weight relative to TTM. The multi-parent-derived line SMBK4 combined white grain with a GP of 46.93%, compared with 100% for the susceptible white-grained parents. Analysis of SMBK3-derived lines indicated that additional genetic factors, including the PHS1 haplotype, also contributed to variation in GP. These results demonstrate the breeding value of TTM and support the use of the TaMyb10-D1-linked KASP marker as a tracking tool, together with phenotypic selection, in TTM-derived white-grained wheat breeding.