Reaction of Prunus Rootstocks to Meloidogyne incognita and M. arenaria in Spain.

Prunus rootstocks were evaluated for their reaction to Meloidogyne incognita and M. arenaria. Most rootstocks were peach-almond hybrids of Spanish origin. In one experiment three selections of Garfi x Nemared (G x N) and Hansen-5 were highly resistant to M. incognita, but four other rootstocks were susceptible showing high galling indices and population increases. In two experiments with M. arenaria, the hybrid selections G x N nos. 1 and 9 were immune, GF-305 and Hansen-5 were resistant, but nine other rootstocks expressed various degrees of susceptibility. All Spanish rootstocks were susceptible to both Meloidogyne species except for the three G x N selections. The root-knot nematode resistant peach Nemared used as a male parent with Garfi was found to transmit a high degree of resistance to M. incognita and immunity to M. arenaria. Progenies of P. davidiana (Ga x D no. 3), a known source of resistance to root-knot nematodes, were susceptible.