The genetic control of tristyly in oxalis section ionoxalis

Abstract

Progeny ratios from crosses utilising six tristylous species of Oxalis section lonoxalis indicate that expression of style forms in this section is generally controlled by two loci which are tightly linked. In diploid species one locus controls the expression of the short style form versus non-short, while the second locus controls the expression of the mid and long style forms. The short allele is epistatic to the mid-long locus, where mid is dominant to long. Control of tristyly is similar in polyploid species, although linkage cannot be detected because of chromosome duplication. Fixation or loss of the mid-long locus would allow the remaining short versus non-short locus to segregate equal numbers of shorts and longs, thus providing a genetic basis for control of distyly. © 1976 The Genetical Society of Great Britain. All rights reserved.