Mechanism of Leaf Vein Coloration and Inheritance of Leaf Vein Color, Flower Form, and Floral Symmetry in Gloxinia

Abstract

Double-flowered gloxinia (Sinningia speciosa) cultivars with foliar variegation might have a greater market appeal as flowering foliage plants. Crosses were made among 16 gloxinia cultivars and their progenies were analyzed to determine the inheritance of leaf vein color, flower form, and floral symmetry. All plants from self-pollinating white-veined cultivars or crosses between white-veined and green-veined cultivars produced white veins. Progeny derived from self-pollinating plants of white-veined cultivars × green-veined cultivars segregated into a ratio of 3 white-veined:1 green-veined. All plants from self-pollinating or cross-pollinating single-flowered cultivars produced single flowers. Progeny of self-pollination or crosses between double-flowered cultivars segregated into a ratio of 3 double flowers:1 single flower. Contingency chi-square tests revealed that leaf vein color and flower form were inherited independently. New gloxinia progenies with homozygous white veins and double flowers were successfully developed from the F2 segregating population. Plants from self-pollinating or cross-pollinating cultivars with actinomorphic flowers produced actinomorphic flowers. A single dominant gene expressed in the homozygous or heterozygous state resulted in the zygomorphic flowers. Independent inheritance was observed between vein color and floral symmetry. Air spaces between the epidermis and the mesophyll cells were observed in the white, but not in the green, leaf vein portions. Net photosynthesis did not differ significantly between the white vein and adjacent green portion of the same leaf.