The genetics of floral development differentiating two species of (Scrophulariaceae)

Abstract

Investigation of the developmental processes responsible for the evolution of the small-flowered, highly selfing Mimulus micranthus from its large-flowered, mixed-mating progenitor M. guttatus, revealed M. micranthus to have both a shorter duration and a higher rate of bud development. Hence flowers of M. micranthus can be considered as progenetic forms of M. guttatus. Genetic analysis of Fj, F2 and backcross generations derived from the cross M. micranthus x M. guttatus provided no evidence for major gene control of development processes responsible for differentiating the two taxa. Furthermore, F2 segregation patterns suggest that duration and rate of development may be genetically independent of one another. Hence, the evolution of small-flowered selfing taxa in Mimulus may reflect selection for rapid development. © 1995 The Genetical Society of Great Britain.