An Integrated Genomics Approach to Study Petunia Development Rate

Petunia (Petunia hybrida) is an important ornamental plant and a model system for genetics studies. Early flowering under non-optimal conditions is an important breeding target for greenhouse production. In this study, an integrated genomics approach was used to develop genomic resources for studying development rate in Petunia. Reference transcriptome assemblies have been constructed for three wild species (P. integrifolia, P. axillaris and P. exserta) and a panel of commercial cultivars (P. hybrida). A total of 89,007 single nucleotide polymorphisms (SNPs) were identified among the wild species, and 62,648 SNPs were identified among the petunia cultivar panel. 15,701 of the SNPs among wild species were computationally converted into cleaved amplified polymorphic sequence (CAPs) markers. In addition, 2,949 SSR markers were identified from the P. axillaris transcriptome. A genotyping-by-sequencing (GBS) approach was utilized to develop high density linkage maps for the RIL populations with 6,759 SNPs placed at P. axillaris x P. exserta map and 2,729 SNPs placed at the P. integrifolia x P. axillaris map. QTL (quantitative trait loci) mapping will be performed to study development rate. This research has increased the current genomic resources for petunia molecular breeding. Markers/genes identified for development rate will be integrated in breeding strategies to develop fast developing petunia cultivars.