Identification of QTL for crop timing and quality traits in an interspecific Petunia population

Genetic mapping in ornamental plant species has lagged behind crop plants from other sectors of agriculture. Here, we describe the generation of a genetic linkage map for the important herbaceous ornamental crop petunia and the identification of QTL for several key crop timing and quality traits, including plant development rate, days to flower and flower number. An F2 population derived from a cross between the progenitor species of cultivated petunia, P. integrifolia × P. axillaris, exhibited transgressive segregation for a broad panel of crop timing and quality traits. A genetic linkage map comprised of 75 simple sequence repeat and six cleaved amplified polymorphic sequence markers spanning 359.1 cM across seven linkage groups was developed and utilized to identify 24 QTL for ten crop timing and quality traits. These included QTL explaining 26.3, 25.9, 26.2 and 43 % of the observed phenotypic variation for flower length, branch number, internode length and the number of flower buds on the primary shoot, respectively. These data provide a foundation for understanding the genetic control of critical traits and identify molecular markers with potential utility to facilitate gene discovery in petunia.