Identification and verification of DTF9.4, a QTL that promotes flowering in common beans (Phaseolus vulgaris L.) under long day photoperiod

Flowering time and maturity are important agronomic traits for common bean (Phaseolus vulgaris), a short-day species in order to adapt to different latitudes and achieve optimal yield. In 2021, a QTL for flowering time, named as DTF-9.4, was mapped on chromosome 09, explaining more than 30% phenotypic variance. Although the studies indicated functional genes exist in this region that controls flowering time, it has not been deciphered at high resolution. In this study, genotyping, and phenotyping of recombinant plants within the QTL region allowed us to test the effect of narrowed QTL at 200 kb and with only two candidate gene annotated, PvFUL1 and PvE1, in Long Day environment. The development of near isogenic lines has allowed us to eliminate the effect of other major genes that segregated in the population (such as PvCOL2) with a major effect on flowering time. The line developed named as dtf-9.4 (Pve1Pvful) had a lower flowering node and early flowering time (node 8 and 40 d) compared with DTF-9.4 line (PvE1PvFUL) (node 15 and 54 d) in long day conditions (14 h light). This finding showed the possible involvement of other circadian clock gene in flowering time regulation in common bean. To determine the effects of these candidate genes underlying QTL, more analyses will be necessary in an effort to link markers, RNA expression, and the phenotype.