Genetic Mapping of Factors Affecting Quantitative Variation for Flowering in Sunflower

Abstract

The number of days from seedling emergence to flowering (DTF) is a major consideration in sunflower (<em>Helianthus annuus</em> L.) breeding because the maximum yield of the crop can only be achieved if the cultivars are phenologically adapted to the production environment. Identification of genetic factors that affect flowering could create opportunities for improved breeding methods and for more fundamental investigations of this important trait and its interactions with the environment. The objectives of this study were to locate quantitative trait loci (QTL) for DTF in an elite sunflower population evaluated in four environments. Two hundred thirty-five F₂-generation plants and their F₃ progeny of a single-cross population of two divergent inbred lines were evaluated in four environments (Fargo, ND and Venado Tuerto, Daireaux, and Balcarce in Argentina). Detection of QTL was facilitated with a genetic linkage map of 205 loci defined by restriction fragment length polymorphism (RFLP) and composite interval mapping. Five QTL of five linkage groups accounted for 89% of the genetic variation for DTF. Gene action was additive at four QTL and dominant at the other locus. Three QTL were detected in all environments and generations. The parental effects and the relative magnitudes of the genetic effects of those QTL were consistent across generations and environments.