Genetic Analysis of Flowering Time in Pansies Using Mixed Major Gene Plus Polygene Inheritance Model

The flowering time of pansy cultivars determines their ornamental application period and the profits of seedling growers. Revealing its genetic basis will be useful for breeding pansy cultivars with desired flowering times. In this study, three inbred pansy lines, DSRFY (D), XXL-YB (X), and EYO (E), with various blooming times were used to generate 12 genetic populations with two hybrid combinations (D × E and X × E). A mixed hereditary model of major and polygenic genes was used to uncover the genetic control of flowering time in pansies. The findings suggested that the flowering times of pansies are characterized by complex traits with continuous variations and normal distributions in the population and are controlled by multiple genes. The genetic basis of flowering time differed between the two hybrid combinations. The trait was governed by minor polygenes with additive-dominant-epistatic effects for D × E crossing combinations hybridized from two parents with a 10-day difference in flowering time, resulting in low heritability. The trait was regulated by two major genes and polygenes exerting additive-dominant-epistatic effects in the X × E hybridization from two parents with a 4-day difference in character, leading to high heritability. Our findings elucidate the genetic basis of pansy flowering time and provide a promising approach to detecting major genes or quantitative trait loci.