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The Journal of Heredity 1997:88(1):31-37
© 1997 The American Genetic Association 88:31-37
research-article |
Nonhomeotic Meristic Flower Mutants in Phacelia dubia
Department of Biological Sciences, East Tennessee State University. Johnson City, TN 37614
Abstract
Two plants with mutant flowers were recovered from the selfed progeny of a field collected seed of Phacella dubia (L.) Trel. A meristic mutant caused the development of an additional component in each of the first three flower whoris (calyx, corolla, and androecium). The effects of a second mutant were restricted to the gynoecium. The normal bicarpellate, two-styled pistil was converted to a triseriate pistil with a trifurcating style and a tricarpellate ovary with three functional placentae that matures into a seed capsule with tripartite dehiscence. The triseriate gynoecium phenotype was controlled by recessive alleles at two nuclear-encoded loci. The mutant gynoecium in P. dubia was morphologlcally similar to the gynoecium typically found in the Polemoniaceae. Mutant phenotypes were expressed on only some of the flowers within plants and expressivity varied among plants. Both mutant phenotypes occurred on plants from an intercross between mutants, but within flowers expression of the two phenotypes was Independent. Levels of expression were higher in F2 Intercross progeny compared to F2 testcross progeny, which suggests the genetic background of the mutants increased expressivity over that of a wild-type background.