PATTERNS OF PHENOTYPIC AND GENETIC CORRELATIONS AMONG MORPHOLOGICAL AND LIFE‐HISTORY TRAITS IN WILD RADISH, RAPHANUS RAPHANISTRUM

Genetic correlations can have profound effects on evolutionary change (Lande and Arnold, 1983; Mitchell-Olds and Rutledge, 1986). Present patterns of genetic correlations in an organism may be caused by pre-existing pleiotropic and developmental relationships among traits and may produce constraints on evolution by natural selection (Cheverud, 1984; Maynard Smith et aI., 1985; Via and Lande, 1985; Futuyma, 1986; Mitchell-Olds and Rutledge, 1986; Barker and Thomas, 1987; Clark, 1987a; Zeng, 1988). Alternatively, selection may directly alter the patterns of genetic correlations, especially in cases in which two or more traits interact to perform a given function (Cheverud, 1984; Lande, 1984; Clark, 1987a. 1987b). In this paper we examine the patterns of phenotypic and additive genetic correlations among 10 morphological and life-history traits in wild radish plants. We hypothesized that some ofthese correlations have been influenced by selection. We predicted that floral and vegetative traits would be uncorrelated and that correlations among the lengths of the corolla tube, pistil and stamens would be higher than the rest of the floral correlations. The results were consistent with most of these predictions. Wild radish, Raphanus raphanistrum (Brassicaceae), is an annual weed of disturbed areas. The hermaphroditic flowers of wild radish are almost entirely selfincompatible (Sampson, 1964; Stanton et aI., 1989) and this species does not propagate vegetatively, so virtually all reproduction depends on successful insect pollination. Wild radish is pollinated by a variety of insects, mainly bees, butterflies, and flies (Kay, 1976;