Identification and mapping of a major gene (Ft1) involved in fructification time in the interspecific cross Coffea pseudozanguebariae x C. liberica var. Dewevrei: impact on caffeine content and seed weight

Fructification time was studied in the interspecific cross Coffea pseudozanguebariae x C. liberica var. Dewevrei (PSE x DEW). Parental species, F(1) hybrids and offspring of the first backcross generation (BC(1)), consisting of F(1) x PSE (BCPSE) and F(1) x DEW (BCDEW) plants, were observed. Fructification time can be split into two independent visual phases: the full-growth period, from blooming up to the end of fruit growth, and the maturation phase, defined by the green to red color change. Fructification time was found to be an additive trait. The full-growth period showed a bimodal distribution in the BCDEW hybrid, suggesting the involvement of Ft1, a major gene that was mapped on linkage group E. The main effects of Ft1 were to lower caffeine content and 100-seed weight, without any impact on chlorogenic acid, trigonelline and sucrose contents. Two molecular markers were identified that bracket Ft1 and which could be used for early marker-assisted selection.