Differences in ploidy levels of inter-specific hybrids obtained by reciprocal crosses between Primula sieboldii and P-kisoana

Differences in ploidy level were found in interspecific hybrids obtained by reciprocal crosses between Primula sieboldii and P. kisoana. When P. sieboldii was used as the maternal parent, the inter-specific hybrids were triploids; when P. kisoana was the maternal parent, the inter-specific hybrids were diploids. The possibility of diploid female gamete formation in P. sieboldii is discussed as a causal factor in the production of triploids occasionally found in crosses between diploids of this species.