Identification of QTL for Plant Architecture and Flowering Performance Traits in a Multi-Environment Evaluation of a Petunia axillaris × P. exserta Recombinant Inbred Line Population

Abstract

Field performance of herbaceous annual plants is largely determined by plant architecture and flowering performance. A Petunia axillaris × P. exserta F7 recombinant inbred line population was grown in four field environments across the United States, and phenotyped for seven plant habit and flowering-related traits: plant height (Height), maximum (MaxWid) and minimum (MinWid) plant width, vigor, compactness (Comp), flowering canopy coverage (Flow) and flower color retention (ColorRet). Robust QTL (rQTL; QTL detected in two or more environments) were identified for all traits except minimum canopy width and were distributed across five of the seven Petunia chromosomes. The largest effect rQTL explained up to 23.8, 19.7, 16.7, 16, 25.7, and 36.9% of the observed phenotypic variation for Flow, Vigor, Comp, ColorRet, Height and MaxWid, respectively. rQTL for Flow, Comp, Height, and MaxWid colocalized on Chr 2, indicating this region could be particularly useful for mining candidate genes underlying important field performance traits in petunia.