Selected Genotypes with the Genetic Background of Vitis aestivalis and Vitis labrusca Are Resistant to Xiphinema index

The ectoparasitic nematode Xiphinema index transmits grapevine fanleaf virus (GFLV) during feeding on grapevine roots, causing fanleaf degeneration in the plant. Hence, resistance breeding is a key to develop novel rootstocks to overcome such threats. In past years, various grapevine species were screened, and a few candidates with partial resistance were identified. However, they were hardly sufficient for viticulture because of their many agronomical defects. To develop reliably resistant rootstocks applicable in viticulture, multiple Vitis spp. genotypes were analyzed using root inoculation with nematodes in glass vials as an early and easy evaluation test. Resistance levels were evaluated 35 days after inoculation based on nematode reproduction factors, focusing on juveniles and eggs. Infection of grapevines with GFLV was analyzed after inoculation with viruliferous X. index. With this fast screening system, putative candidates with resistances against X. index have been identified for future breeding programs. Particularly, genotypes with the genetic background of Vitis aestivalis and Vitis labrusca were found to be nematode-resistant.

Automated summary

In order to develop reliably resistant rootstocks applicable in viticulture, researchers conducted analysis of multiple Vitis spp. genotypes through root inoculation with nematodes in glass vials as an early and easy evaluation test. Resistance levels were assessed based on nematode reproduction factors after 35 days of inoculation, with a focus on juveniles and eggs. Through this fast screening system, potential candidates with resistances against X. index have been identified for future breeding programs, particularly those with genetic backgrounds of Vitis aestivalis and Vitis labrusca were found to be nematode-resistant.