Determining the Genotypes for and Genetic Distances between Two Loci Controlling Caladium Leaf Spotting and Main Vein Colors

Caladiums are grown in the containers and landscapes for their long-lasting, colorful leaves. Leaf traits are very important for caladium cultivars’ ornamental value. Information about caladiums’ genotypes for leaf traits and the genetic distances between the loci controlling leaf traits can help plant breeders to design appropriate hybridization schemes and estimate breeding population sizes needed to achieve specific breeding objectives. In this study, 45 crosses were made among 13 caladium cultivars and 16 breeding lines, and their progeny were phenotyped for leaf spotting and main vein color, two important leaf traits in caladium. Phenotyping results showed that eight red-veined caladium cultivars (Carolyn Whorton, Florida Fantasy, Florida Red Ruffles, Florida Sweetheart Freida Hemple, Red Flash, Tapestry, and White Queen) are heterozygous at the main vein color locus (V), with the genotype V^rV^g. Among the 14 caladium breeding lines that exhibit red main veins, two genotypes were observed: 11 breeding lines have the V^rV^g genotype and three breeding lines possess the V^rV^w genotype_. Four caladium cultivars (Aaron, Florida Moonlight, Gingerland, and Miss Muffet) and two breeding lines that have white main veins have the V^wV^g genotype, as expected. The green veined ‘Florida Elise’ and three breeding lines are homozygous and carry the V^gV^g genotype. Three spotted cultivars (Gingerland, Miss Muffet, and Red Flash) and four spotted breeding lines are heterozygous at the leaf spotting locus (S), with the genotype Ss. ‘Gingerland’ and ‘Miss Muffet’ were crossed with ‘Candidum’, a non-spotted cultivar to determine the genetic distance between the S and V loci, which were found to be linked in a previous study. Nearly 6000 progenies were obtained and phenotyped, and segregation data indicated a tight linkage between the two loci.