FLOWERING LOCUS T, GIGANTEA, SEPALLATA, and FRIGIDA homologs are candidate genes involved in white lupin (Lupinus albus L.) early flowering

White lupin (Lupinus albus L.) is a legume plant rich in seed protein and appreciated in crop rotation due to improvement of soil structure and fertility. Primitive white lupin accessions are late flowering unless subjected to cold period during seed germination. It is an undesirable trait in spring-based agriculture. Moreover, white lupin is very susceptible to anthracnose, and the only known resistant lines are late-flowering landraces from Ethiopia. Tracking of early flowering during white lupin breeding has been challenging for many years due to the lack of knowledge on underlying genes and limited molecular resources. To address this issue, we performed genomic and genetic analysis of white lupin germplasm differing by time to flowering, including mapping population derived from Kiev Mutant (early flowering, anthracnose susceptible) and P27174 (late flowering, anthracnose resistant). Thirty six flowering induction pathway genes were subjected to molecular marker development and linkage mapping. Markers representing 24 homologs were localized in 17 linkage groups. Four quantitative trait loci (QTLs) of flowering time, consistent across field and greenhouse experiments, were localized in three linkage groups. Three QTLs absolutely co-localized with GIGANTEA, FLOWERING LOCUS T, and SEPALLATA 3 gene–based markers whereas one neighbored the FRIGIDA 3 marker by 3.6 cM. Analysis of narrow-leafed lupin genome regions highly syntenic to these QTLs highlighted these homologs as candidate genes for early flowering. Molecular markers developed in the present study should have facilitated the issue of tracking late-flowering alleles in further white lupin breeding approaches involving primitive Ethiopian germplasm.