An Inhibitor Gene for Flower Standard Development in Korean Lespedeza 1

Crosses were made between two lines of Korean lespedeza ( Lespedeza stipulacea Maxim.) with mutant flower characters. F 1 , F 2 , F 3 , and F 4 data were used to determine whether the mutant gene s for small purple flower standard and the mutant gene a for fused accessory wings and no standard (formerly designated narrow white standard nws ) were alleles, whether dominance between the two existed, and whether there was any linkage or recessive epistasis involved if the two genes were not alleles. F 1 plants from this cross all produced normal flowers, indicating that the two genes >s > and >a were not alleles. Flower data from the F 2 plants indicated a segregation ratio of 9 normal standards: 3 small purple standards: 4 fused accessory wings. Flower data from the F 3 and F 4 generations provided further support for the proposed 9:3:4 F 2 ratio. All evidence indicated that the genotypes of the mutant parent with small purple flower standard, the mutant parent with fused accessory wings, and the F 2 plants were ss AA, SS aa , and Ss Aa , respectively, and that no linkage was involved. It was concluded that the gene a in the homozygous condition completely inhibits flower standard development (recessive epistasis), regardless of whether the gene for standard is homozygous dominant (SS), homozygous recessive ( ss ), or heterozygous ( Ss ). When flower standard development is inhibited by the gene a , it is suggested that fused accessory wings develop in place of the flower standard.