Identification and quantitative trait locus mapping of Tartary buckwheat pre-harvest sprouting

Tartary buckwheat (Fagopyrum tartaricum) is particularly vulnerable to pre-harvest sprouting (PHS) due to its extended flowering and fruiting cycle, especially during periods of prolonged rainfall. This susceptibility has significant adverse effects on yield, quality and post-harvest processing. In this study, a recombinant inbred lines (RILs) population (XJ-RILs) was developed from a cross between the PHS-susceptible Tartary buckwheat variety 'Xiaomiqiao' (female parent) and the highly PHS-resistant variety 'Jinqiaomai 2' (male parent). Key traits, including germination percentage, germination energy, germination index, field PHS (PHS-F) and simulated PHS (PHS-S), were evaluated, and a quantitative trait locus (QTL) mapping analysis was performed.

(i) PHS-S was strongly and significantly correlated with PHS-F. (ii) A total of 11 QTLs associated with seed germination and 14 QTLs related to PHS were identified. Notably, the major QTL cluster qPHS8-1 was consistently detected and mapped within the interval of 8.53-9.65 Mbp on chromosome Ft8. (iii) Genotyping of 221 XJ-RILs across eight chromosomes revealed five residual heterozygous lines carrying a heterozygous interval of qPHS8-1 cluster, with inbred line R56 being particularly suited for the fine mapping of qPHS8-1.

The PHS-S test, conducted on entire Tartary buckwheat spikes, is an effective and comprehensive method for assessing PHS resistance in this crop. QTL mapping identified qPHS8-1 as a major locus for PHS resistance, and inbred line R56 offers a promising resource for further fine mapping of this cluster. © 2025 Society of Chemical Industry.