Flower Variegation in Sweet Pea (Lathyrus odoratus L.) Is Regulated by a Single Recessive Gene That Is Epistatically and Recessively Suppressed by a Pigmentation Gene

Abstract

In sweet pea cultivars, a day-neutral winter-flowering type, which is cultivated for cut flowers in greenhouses in Japan, shows less phenotypic variety than a long-day summer-flowering type, which is cultivated in Europe. We would like to introduce the variegated-flower phenotype, which is currently found only in the summer-flowering type cultivars, into winter-flowering plants so as to expand the phenotypic diversity of the winter-flowering plant type. As the first step, we examined the inheritance of the variegated-flower phenotype and its possible linkage with pigmentation and flowering-type phenotypes. The segregation ratios of flower pigmentation phenotypes in progenies of crosses between variegated, fully pigmented, and white-flowered plants revealed that the variegated-flower phenotype is regulated by a single recessive gene, and the phenotype is epistatically and recessively suppressed by a pigmentation gene. We confirmed that the winter-flowering type predominant in Japan is regulated by a single recessive gene, as previously reported. Our data also indicate that the genes controlling the variegation, pigmentation, and flowering type segregate independently. These findings suggest that the winter-flowering phenotype can be fixed in the generation in which the phenotype appears, whereas the variegated-flower phenotype can be fixed at the generation in which the white-flowered phenotype does not appear in the self-progeny.