Wednesday, August 10, 2016
Georgia Ballroom (Sheraton Hotel Atlanta)
Petunia is a popular bedding plant and a major commercial ornamental crop in the world. Identification of valuable alleles in wild species and introgression into elite germplasm are important for breaking current barriers in petunia breeding. In this study, two F7 recombinant inbred populations derived from the crosses between P. axillaris × P. exserta (AE) and P. integrifolia × P. axillaris (IA) were phenotyped for days to anthesis (DTA), flower counts (FC), flower diameter (FD), flower development rate (FDR), flower length (FL), plant height (PH), plant spread (PS), and plant size (PZ) in central Florida, U.S.A in 2014 and 2015. Transgressive segregation was observed in both AE and IA F7 populations for eight and five traits, respectively. The broad-sense heritability on a two-year basis for eight traits varied from 0.38 (FC) to 0.82 (FL) (IA F7 population), and 0.21 (DTA) to 0.62 (FL) (AE F7 population). Two single nucleotide polymorphism (SNP) bin maps that spanned 274.7 cM containing 343 bins (AE F7 population) and 220.2 cM comprising 536 bins (IA F7 population) were used to identify quantitative trait loci (QTL) for these traits. In AE F7 population, 22 QTL were identified and localized to linkage groups (LGs) 1, 2, 3, 4 and 7. Eleven of the QTL (50.0 %) were consistent in both years, and some major QTL explained up to 26.8%, 25.3%, and 22.6% of the phenotypic variance for FDR, FD, and FC, respectively. In the IA population, we detected 26 QTL in LGs 1, 2, 3, 4, and 6; 12 (46.2%) of the QTL were consistently identified in both years, and some major QTL explained a total phenotypic variation up to 30.2%, 35.3% and 47.1% for PS, FL, and FD, respectively. A number of the identified QTL were co-localized in several chromosomal intervals; these intervals could be very valuable for petunia breeding and introgressing desirable alleles into commercial petunia cultivars.