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The valorisation of genetic variability through the identification suitable genotypes for traits such as yield and must quality is an effective strategy used for grapevine selection. Currently, climate change-driven heat waves and drought affect plant growth and wine quality, but little information is available on intravarietal variability regarding responses to stress. In the current work, the intravarietal genetic variability of the Portuguese variety Arinto was studied for yield, must quality, and tolerance to abiotic stress. An innovative approach using rapid, and nondestructive measurements of surface leaf temperature (SLT), Normalized Difference Vegetation Index (NDVI), Photochemical Reflectance Index (PRI), and chlorophyll content (SPAD), was used in an experimental population of 165 clones of Arinto installed according to a resolvable row-column design with 6 replicates. Also, yield and quality characteristics of the must were quantified. Linear mixed models were fitted to the data, and the empirical best linear unbiased predictors (EBLUPs) of genotypic effects for each trait were obtained as well as the coefficient of genotypic variation (CVG) and broad sense heritability. The results enabled the selection of a group of genotypes with increased tolerance to stress, which maintained the must quality of Arinto.

Since the last decade of the last century, it is known that many old grapevine varieties are descendants of other varieties through natural crossing. Portugal has an important program for the conservation of representative samples of intra-varietal variability of all autochthonous varieties, managed by the Portuguese Association for Grapevine Diversity (PORVID), which makes looking for genotypes with dubious identification an important activity from a perspective of its valorisation. This communication presents the results of the molecular analysis of 5,000 samples (accessions) from the PORVID’s collection, using nine microsatellite loci currently recommended by the International Organization of Vine and Wine (OIV) for genetic grapevine identification. The results obtained confirmed the molecular identity of 4,220 samples corresponding to 214 varieties present in the official list of Portuguese varieties. In 780 samples, 95 profiles with a plural number of accessions revealed not to be listed in the Vitis International Variety Catalogue (VIVC) database, corresponding to possible varieties either descendent from natural crossing from at least one known parental variety, or from undetermined origin. Furthermore, the need for a comprehensive strategy aimed at uncovering other hidden varieties is discussed to prevent their imminent loss, deepen understanding of their origin, and add economic value and sustainability to the vine and wine sector.

The antiquity and diversity of traditional grapevine varieties guarantee a strong historical and natural character and add high economic value to viticulture and wine. A high level of intra-varietal diversity of quantitative traits was naturally created and accumulated over centuries. Nowadays, this diversity allows one to carry out selection within a variety and adapt it to the most diverse environmental, agricultural, and market contexts. However, an unusually intense process of genetic erosion of intra-varietal diversity broke out in the 1980s and threatens to destroy within a few decades the diversity created over centuries and millennia. Therefore, the definition of strategies and methods for conserving and exploring intra-varietal genetic variability is crucial for the sustainability of viticulture rich in history and traditions. Those strategies are presented in this work.

Clonal selection allows control of virus diseases and selection of genotypes on agronomic, viticultural or enological criteria. Clonal selection has the major drawback that it impoverishes genetic diversity and exposes growers to environmental instability of clones (genotype X environment interaction). Clonal selection has become the almost unique way of propagating plant material for vineyards, hence threatening the genetic diversity of the grapevine. For major grapevine varieties, some genetic diversity is maintained in institutional collections. However, this way of conservation is insufficiently developed, it is expensive and remains fragile. A cost effective way to preserve intra-varietal diversity is to maintain a limited proportion of mass selection in vine propagation. Private clonal selection can also contribute, in a more limited way, in maintaining genetic resources. Another approach to carry out conservation and selection of grapevine is the methodology followed in Portugal. This strategy is exemplified with the conservation/selection of an ancient Portuguese variety. The work begins with the “ex situ” conservation of a representative sample of the intravarietal diversity of the variety, which, in practice, corresponds to a large field trial with hundreds of clones under an experimental design suitable for reducing random variation of quantitative traits. From evaluating those traits (yield and must quality traits), the intravarietal diversity is quantified and the range of the predicted genotypic effects for each of those traits is analyzed. Different mass selections (polyclonal selections) are carried out for distribution and planting of new vineyards. These different mass selections provide high economic gains and also the preservation of diversity in a complementary manner to that which started the work on-farm conservation.

Grapevine (Vitis vinifera L.) diversity richness results from a complex domestication history over multiple historical periods. Expansion of human activity led to the creation of thousands of varieties with extensive phenotypic diversity. Unfortunately, the recent favoring of specific varieties/clones, and the globalization-driven exposure to pathogens, has led to extensive genetic erosion in this widely cultivated and economically significant crop. Fighting this genetic erosion whilst addressing issues of resilience to climate change, yield and other traits, requires a crucial understanding of the genetic basis of grapevine variation. This scientific field has witnessed significant advances due to the use of genomics approaches, enabled by Next Generation Sequencing. Here, NGS-driven whole genome resequencing strategies have been used to tackle multiple aspects associated with the extant genetic diversity present in grapevine germplasm, including a clarification of different features of its recent evolutionary history that suggest a meaningful role of the Iberian Peninsula in grapevine domestication. These different aspects of grapevine biology, which require genome-level analysis, employ multiple genomics and bioinformatics strategies that help bridge the gap between population history, genomic variation and gene function. Funding: Fundação para a Ciência e Tecnologia (FCT/MCTES) for project GrapeVision (PTDC/BIA-FBT/2389/2020) and support to H.A. (CEECIND/00399/2017/CP1423/CT0004); FCT/MCTES and POCH/NORTE2020/FSE for support to S.F. (SFRH/BD/120020/2016); FCT/MCTES and POPH-QREN/FSE for support to M.C. (CEECINST/00014/2018/CP1512/CT0002). [ABSTRACT FROM AUTHOR]