With nearly 40.000 planted hectares, Argentina is home to the greatest genetic reserve of Malbec in the world. A native of Cahors, the offspring of Madeleine Noir de Charentes and Prunelard, Malbec has remained in use and prevalent over millennia—a testament to its resilience and popularity. While the importance of this varietal in France has waned since the mid-19th century—a consequence, in part, of the devastation caused by phylloxera—Malbec found a second home in Argentina, and notably in the province of Mendoza, where it was introduced around 1853 by the French agronomer Michel Aimé Pouget. Today, the region holds a veritable genetic treasure of pre-phylloxeric, ungrafted vines—our efforts are aimed at highlighting this treasure and enduring its survival.
This collaborative, interdisciplinary study brings together scholars in the fields of genetics, viral diseases, viticulture, enology, and history to shed light on the fundamental role of Argentine Malbec in the larger preservation and survival of this varietal. Drawing on evidence from ongoing research, our presentation considers the broader importance of genetic diversity today, highlighting the uniqueness of the Argentine context and detailing our own role in the preservation of this varietal: in relation to both the health of our vines and their genetic diversity. Our main aim is the recognition of this varietal as an ancient, emblematic variety and cultural patrimony of humanity. We are impelled in this endeavor by the particular circumstances of Argentina—the unique diversity of Malbec in this area—as by the need to safeguard the future of Malbec in a context of climatic change.
Genetic diversity of Malbec cultivar in Argentina: genetic diversity is low between clones within a clonal-propagated cultivar such as grapevine. However, genetic events, such as somatic mutations, still occur and accumulate over time. Grapevine cultivars were derived from sexual crosses and clonally propagated to preserve their unique traits. Malbec presents remarkable clonal phenotypic diversity and a great capacity for adaptation. However, little is known about its clonal genetic diversity. The first large-scale results were recently achieved using whole genome resequencing for four different clones and the identification of 941 informative polymorphisms (DOI: 10.1038/s41598-021-87445-y). After evaluating 214 Malbec accessions, 14 different genotypic patterns were identified that were grouped into two genetically divergent clonal lineages (FR and AR). The genotypes included in the FR group are closely related to the accessions close to the origin of this cultivar in France or introduced into this country during the last 30 years. The genotypes of the AR group are closely related to accessions with a longer clonal propagation time in Argentina (>70 years), suggesting a closer link with those first plants introduced from France during the 1850s. In other words, what is usually observed at the phenotypic expression level now has genotypic support.
A more immediate threat to Argentine Malbec is viral diseases: Argentina maintained a strikingly low viral presence until the 1990s, a situation that has since shifted—a negative outcome of the industry’s explosive export boom—despite strict legislation and governmental control on the entry of plant materials. Grapevine is affected worldwide by a large number of pathogens with a potentially high economic impact. They include more than 80 known viruses, several of these associated with severe diseases transmitted through propagation material. Thirteen of more than 80 viruses have already been reported in Argentina. While cultural practices are still employed to handle viral outbreaks (primarily the replacement of diseased vines with healthier new ones), the main tool used for the control of viral diseases is the use of virus-free planting stock, obtained through sanitary selection. This selection is based on an evaluation of the sanitary status of promising plants, with the aim of choosing virus-free plants using the most advanced diagnostic techniques. Yet the rising number of viral entities described in recent years has made healthy vines increasingly hard to find. As the main genetic reserve of Malbec in the world, Argentina is ideally suited to a trial selection program. However, the selection of healthy Malbec genotypes could lead to a severe process of genetic erosion. Consequently, the use of advanced techniques for sanitation (meristem tip culture, somatic embryogenesis) of highly valuable genotypes is an attractive pathway for preserving and valorizing the genetic diversity of this cultivar of such significance for the worldwide wine industry. This would increase our ability/readiness to adapt to changing climatic conditions. Inefficient use of resources: plants with viruses produce less.
In 1995, under the direction of the Catena Institute of Wine, we initiated a program geared towards the preservation of 135 pre-phylloxeric, ungrafted Malbec clones drawn from old vineyards in the region of Mendoza, which we later named the Catena Cuttings. Over the past five years, we’ve taken this project a step further, building a nursery of virus-free plants including the Catena Cuttings and exemplars from other varietals such as Cabernet Sauvignon, Chardonnay, Pinot noir and the native Criolla. Malbec has been grown and vinified for over a thousand years. Key to its future is the study and preservation of genetic diversity, and the propagation of virus-free plants.