SPECIES COMPOSITION OF JAPANESE PLUM FOUNDING CLONES AS REVEALED BY RAPD MARKERS

Early domestication of diploid plums in the United States was focused on native North American plum species until Luther Burbank imported several Japanese plum (P. salicina Lindl.) seedlings from Japan and intercrossed these with Chinese plums, Eurasian plums, and native American plums. His released plums, which later became founding clones of Japanese-type plums in the United States, were mainly multispecies hybrids. The major founding clones for Japanese-type plums for the California gene pool are ‘Santa Rosa’, ‘Eldorado’, and ‘Gaviota’; and for the southeastern USA are ‘Methley’, ‘Santa Rosa’, and ‘Mariposa’. However, the parentage and consequently the species composition of these multispecies hybrids is poorly documented and has been based on their morphological traits. The objective of this study was to estimate species composition of California and southeastern diploid plum founding clones with 168 RAPD markers generated with eight primers (C10, E6, G6, J5, J8, K3, K18, and N10). The species composition was assessed with sets of diagnostic RAPD markers and was estimated with the RAPD marker frequency data. This analysis confirms that P. salicina, P. simonii, and P. cerasifera are in the backgrounds of these founding clones but raises questions about the P. americana parentage proposed in the development of the founding clones ‘Santa Rosa’ and ‘Gaviota’.

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