Intra-specific Polyploidy and Possible Occurrence of Some Genetic Types for Pollen Development in Cayratia japonica, Vitaceae.

抄録

Cayratia japonica showed intra-specific polyploidy of x=20, i.e., 2n=40 (diploid) and 60 (triploid). Individuals with 2n=40 produced fruits, and formed 20 bivalents at metaphase I in meiosis, but their pollen fertilities widely varied from about 30 to 90%. Individuals with 2n=60 did not produce any fruits, formed a variable number of trivalents, bivalents and univalents at metaphase I, and showed low pollen fertilities of less than 30%. The possible occurrence of some genetic types for pollen development in diploids is discussed.