P1080QTL Identification for Plant and Flower Traits in Petunia Using Recombinant Inbred Lines and SNP Markers
QTL Identification for Plant and Flower Traits in Petunia Using Recombinant Inbred Lines and SNP Markers
Petunia is one of the most popular bedding flowers worldwide for its high aesthetical performance. Petunia breeding is conducted in numerous countries. The identification and localization of quantitative trait loci (QTL) controlling important plant and flower traits could facilitate petunia breeding. In this study, 173 recombinant inbred lines (RILs) derived from an interspecific cross between Petunia axillaris and Petunia exserta were phenotyped for plant size (PZ), flower diameter (FD), flower length (FL), flower counts (FC) and days to anthesis (DTA) in 2014 and 2015. These RILs showed transgressive segregation for all traits studied. The broad-sense heritability on a two-year basis ranged from 0.21 (days to anthesis) to 0.62 (flower length). A single nucleotide polymorphism (SNP)-based genetic map, consisting of 343 bins and covering a total of 274.7 cM across seven chromosomes, was used for QTL identification. A total of 12 QTL on chromosomes 1, 2, 3, and 4 were discovered for the five traits. Seven QTL, including one for PZ, two for FD, one for FL, and three for FC, were consistently detected across both years. The two QTL for FD collectively explained up to 46.3% of the observed phenotypic variation in flower diameter. There were five additional QTL that were detected in either 2014 or 2015, and these QTL showed the considerable interactions with the environment and/or cultivation conditions. Multiple QTL controlling PZ, FC, and DTA were identified on two adjacent regions of chromosome 2, suggesting these regions may have value for petunia breeding.