A series of chloroplast and nuclear probes were used to examine restriction fragment length polymorphisms (RFLPs) in kiwifruit (Actinidia deliciosa) and three of its closest relatives. The four species fell into two pairs, with A. chinensis and A. deliciosa closely related but some distance away from the other two species, A. latifolia and A. eriantha. The results are consistent with the hypothesis that the diploid species, A. chinensis, is a precursor of A. deliciosa, which is hexaploid. © 1990 Springer-Verlag.