Resistance of Rosa species and cultivars to Pratylenchus penetrans

Abstract

Methods to screen for resistance to root-lesion nematode Pratylenchus penetrans in Rosa were modified to screen-rooted materials. Sixty days after rooting, plants were transplanted into 50-mL pots filled with river sand and each inoculated with 500 P. penetrans in 400 μL water 10 days later. The inoculated plants were fertilized weekly and incubated in a growth chamber or a greenhouse for 5 months when nematodes were extracted from the sand and root system and enumerated. When used for screening of the 131 Rosa accessions, this approach allowed the observation of a large variation in host suitability. While a majority of the accessions supported the multiplication of P. penetrans, previously reported resistance of R. multiflora 'K1' and R. virginiana to P. penetrans was confirmed. Rosa laevigata anemoides allowed a significantly lower nematode multiplication than the currently prevalent rootstock R. corymbifera 'Laxa'.