BY520-9, A Peach Rootstock for the Southeastern United States that Increases Scion Longevity

Abstract

Additional index words. Prunus persica, Meloidogyne, Criconemella, peach tree short life BY520-9 is being provisionally released as bulk seed for industry testing as a rootstock for peach and nectarine [Prunus persica (L.) Batsch] where root-knot nematode (Meloi-dogyne spp.), peach tree short life (PTSL) associated with ring nematode (Criconemella xenoplax (Raski) Luc & Raski], or both are a problem. BY520-9 consists of open-pollinated seed of 69 selections from B594520-9, which traces back to S-37 and Nemaguard. Origin One of the early goals of U.S. Dept. of Agriculture (USDA) stone-fruit breeding programs in Fort Valley, Ga.; Belts-vine, Md.; and Fresno, Calif., was the development of a well-adapted, root-knot-nematode-resistant peach rootstock. BY520-9 lineage traces to a 1954 cross made by J. Weinberger at Fort Valley of FV235-4 × FV234-1 (Fig. 1). FV235-4 was an open-pollinated seedling of S-37, itself a seedling of an unknown flowering peach. S-37 was used in California because of its resistance to M. incognita (Kofoid and White) Chitwood (Lownsbemy et al., 1959) and high vigor, but has fallen into disuse. S-37 apparently segregates for nectarine, weeping habit, and white flowers (Werner et al., 1985), but clonal material was unavailable for testing. FV234-1 was released in 1959 for testing and, in 1961, was named Nemaguard for its resistance to. both M. incognita and M. javanica (Treub) Chitwood (Lownsberry et al., 1959). It is still used widely in California and elsewhere. From seed of Weinberger's cross planted at Fresno in 1955, seedling F51-25 was selected. Seedlings of F51-25 were found by H.W. Fogle and J.M. Good to be resistant to root-knot nematode in tests at the USDA in Beltsville, and subsequently planted in the field under the designations B594503-B594538. Seedlings of these plants were later