Back to the roots–direct producers as the future of viticulture?

Abstract

Until the second half of the nineteenth century, viticulture in Europe was free from phylloxera (Daktulosphaira vitifoliae) and grapevines were cultivated on their own roots. With the introduction of phylloxera in 1863, viticulture came under severe pressure as the pest eradicated more than 2.5 million hectares of viticultural area. This crisis spurred extensive grapevine breeding activities in Europe based on North American wild Vitis species and hybrids from North America, which were resistant or tolerant against phylloxera. The goals were to produce new wine grape cultivars tolerant to phylloxera (the so-called “direct producers”) and to establish phylloxera-resilient rootstocks for grafting. In the long term, breeding pest- and disease-resistant direct producers proved unsuccessful, mainly due to of the poor wine quality of these cultivars, leading breeders to abandon this approach. However, by the early 20th century, rootstock breeding created several highly resilient rootstock cultivars based on North American wild Vitis species, which grew well in European soils and were compatible for grafting with the European wine grape cultivars. The widespread adoption of these rootstocks, alongside less effective quarantine measures and chemical treatments, saved European viticulture at the time and remains the most effective and economical solution for combating soil-borne pests today.

With advancements in grapevine genetics and molecular biology, research into the resistance traits of rootstocks and wild Vitis species against phylloxera became possible.

In 2009, the first resistance locus against phylloxera was identified. Several other loci have been described in recent years. The knowledge of these resistance loci and their associated molecular markers enable breeders to perform early selection of phylloxera-resistant rootstocks–and wine grape cultivars. This knowledge-driven approach, which is already the standard method for breeding fungus resistant grapevine cultivars, will allow breeding of phylloxera-tolerant cultivars with high wine quality and overcoming the problems earlier breeders faced when trying to establish direct producers.

This talk aims to summarize recent developments in phylloxera resistance research and to discuss the chances and opportunities this knowledge has for breeding future direct producer grapevine cultivars, while also reflecting on the research that is still needed to develop highly resistant and durable direct producers.