RESISTANCE AMONG NEW PRUNUS ROOTSTOCKS AND SELECTIONS TO ROOT-KNOT NEMATODES IN SPAIN AND FRANCE

New Prunus rootstocks and selections were evaluated for their reaction to Meloidogyne arenaria (Neal) Chitwood, M. incognita (Kofoid & White Chitwood), or M. javanica (Treub) Chitwood. Most of the clones were peach-almond hybrids (P-AHs) [P. persica (L.) Batsch x P. dukis (Mill.) D.A. Webb] or plums of Spanish and French origin. In a first experiment, the P-AH Hansen 2-168 and plums GF-31 (P. cerasifera Ehr.) and GF 8-1 (P. cerasifera x P. munsoniana Weigth et Hedr.) were highly resistant to the mixture of five isolates of M. javanica. The P-AHs Barrier and Titan x Nemared were resistant and moderately resistant, respectively; GF-677, MB 3-13, MB 2-2, and MB 2-6 were susceptible. In the second and third experiment, the plums P 1079, P 2175, the hybrids Afgano (P. dasycarpa Ehrh.), G x N No 22, and G x N No 15, both P-AHs, and Nemared peach were highly resistant to mixtures of five isolates of M. incognita or M. arenaria. The plums P 2980 (P. cerasifera) and GF 8-1 tested against either root-knot species were also highly resistant. Cachirulo x (G x N No 9), a P-AH, showed less resistance to M. arenaria than to M. incognita. Montclar (P. persica) and the P-AHs Torrents AC and GF-677 were susceptible to both species.