Latitudinal cline and intrapopulational differentiation in leaf shape of wild radish in Japan.

Abstract

The spatial pattern of variation in the leaf shape of the Japanese populations of the wild radish (Raphanus sativus L. var. raphanistroides MAKINO) was investigated by examining herbarium specimens, natural and cultivated samples. Three genetically determined leaf forms were included in natural populations of the wild radish. The pinnatifid (PF) leaf form was predominant, the lyrate (LY) leaf form was observed in a low frequency while the pinnatisect (PS) leaf form was rarely found. The progeny tests suggested that the LY leaf form is controlled by a single gene which is recessive to its alleles specifying the PF form. The proportlons of leaf morphs in the wild radish were similar to those in the Japanese radish, while the localization of the LY morph was detected in latitudinal and microgeographic scales. The frequency of the LY morph and magnitude of polymorphism increased with the increase in the latitude of the locality of the population. A high level of diversity for the leaf shape was recognized in many populations, while ecological preference was not detected among the different types.