A Search for More Durable Grape Rootstock Resistance to Root-knot Nematode

Abstract

The resistance levels of 6-19B, 10-17A, 10-23B, RS-3, RS-2, Teleki 5C, and Ramsey rootstocks to populations of Meloidogyne incognita R3, M. chitwoodi mixed Meloidogyne spp., Meloidogyne sp. pt. Ramsey, and two resistance-breaking populations of M. arenaria were compared in microplots . Freedom and Harmony rootstocks were included as commercially resistant checks and Cabernet Sauvignon was included as a susceptible check. Each replicate was inoculated by adding field soil containing each nematode population. The level of resistance was determined by comparing final population levels of J2 in soil and number of females and eggs per gram of root over a two-year period. All rootstocks suppressed reproduction of the common Meloidogyne spp.; however, 6-9B, 10-17A, 10-23B, RS-3, and RS-2 only suppressed reproduction by the two resistance-breaking populations of M. arenaria. These data suggest that these five rootstocks exhibit a more durable root-knot resistance than commercially available rootstocks. The population of M. arenaria pt. Freedom was unavailable for study during the original selection process of these five rootstocks.