Portugal's history of viticulture and vinification covers many centuries and has included the use of an extensive number native varieties. In addition, through experimentation and field trials a number of new varieties have emerged and are now playing key roles in producing the country's wide array of wines. The relative absence of many international varieties such as Cabernet Sauvignon, Chardonnay and Semillon is another characteristic of this country's wine industry, although in recent decades many of these varieties have been brought into wider use as the lists below reveal. Portugal's wine production in 2019 was 6.5 million hectolitres (Mhl), consistent with its annual average since 2015, and the forecast for 2020 is also 6.5 Mhl. This industry makes an important contribution to the country's annual income by attracting a vigorous local market and by being exported all over the world with France, the United States, the United Kingdom, Brazil and Germany as the main destinations. Evidence gained from recent research may suggest that the industry has not yet reached its maximum level of winegrape output efficiency. Among other wine exporting nations, Portugal was ranked as the world's 9th largest in 2018-2019. == Identifying a variety - the problem with homonyms and synonyms == Wine grape varieties are usually known by what is called the "prime name", and it is under this name they are listed in official and academic documents such as the Vitis International Variety Catalogue (VIVC) and Kym Anderson et al.'s Which Winegrape is Grown Where?: A Global Empirical Picture. Sometimes in a particular country, a variety may have a prime name which is different from its prime name in the international context. For example, the variety called Tempranillo or Tempranillo Tinto internationally is officially listed in Portugal as Aragonez, and is also known in different regions as Tinta Roriz or Aragonês. Along with the prime name, the other names, that is homonyms and synonyms, by which each variety is known are also included in the lists below. These homonyms and synonyms indicate how many of the wine grape varieties grown in Portugal are known by more than one name both within the country itself and internationally. For example, the synonyms for Tinta Caiada (also called Tinta Lameira in Portugal, and known elsewhere by its Spanish name, Parraleta), listed by country of origin, are: Bonvedro, False Carignan (Australia); Espagnin Noir (France); Bastardão, Bonvedro, Bomvedro, Lambrusco de Alentejo, Monvedro, Monvedro do Algarve, Monvedro de Sines, Murteira, Olho Branco, Pau Ferro, Perrel, Preto Foz, Preto João Mendes, Tinta Caiada, Tinta Grossa, Tinta Lameira, Tintorro, Torres de Algarve (Portugal); Bonifaccencu, Bonifacienco, Carenisca, Caricagiola (Sardinia); Bastardo, Cua Tendra, Parraleta, Parrel, Salceño Negro (Spain). In an international context, some varieties have more than 200 or 300 homonyms or synonyms: over 250 for Chasselas Blanc, about 300 for Pinot Noir, and close to 350 for Moscatel Galego Branco. Often homonyms or synonyms of a particular variety are a direct translation from one language or dialect to another. Pinot Blanc, for example, originated from France and therefore its prime name is in French, but in Italian it is called Pinot Bianco (bianco = white) and Pinot Bijeli (bijeli = white) in Croatian and languages or dialects related to Serbo-Croatian. Sometimes, when a variety originated from a particular place or has been grown there for a long time, it can be given a local name that reflects that association. Arinto, for example, has among its synonyms Arinto d'Anadia, Arinto de Bucelas, Arinto do Dão and Arinto do Douro as well as Asal Espanhol, Pé de Perdiz Branco and Terrantez de Terceira. Further confusion has arisen when a particular homonym or synonym has been given to more than one variety. Espadeiro, for example, is the prime name for a variety; but as Wein-Plus warns, "It must not be confused with Camaraou Noir, Manseng Noir (both from France), Padeiro, Trincadeira Preta or Vinhão (all five with the synonym Espadeiro), despite the fact that they seem to share synonyms or have morphological similarities. Probably the greatest confusion of identity has come about through misidentification, misnaming, or mislabelling. Some growers, for example, have found themselves with vines for which they have no formal identification and have based their decision on observation or even guesswork; so if the vine, grape or seasonal behaviour is similar to that of another variety, it is not surprising that the variety is given an incorrect name. The occurrence of mislabelling was also frequent in the past, especially when the gathering and exchanging of cuttings were carried out informally and without some form of control. New legislation and strict administration have reduced but not eliminated this risk. == Ampelography and the establishment of the National Ampelographic Collection == A major step in mapping and conserving Portugal's unique grape profile was the establishment in 1988 of the Coleção Ampelográfica Nacional (National Ampelographic Collection or CAN), a germplasm bank containing as many of the country's unique native varieties as have been found so far along with those varieties that have been introduced from elsewhere. The collection is located at the Instituto Nacional de Investigação Agrária e Veterinária, I.P. (National Institute for Agricultural and Veterinary Research or INIAV) in Dois Portos, and has been described as the "national reference collection" and "in addition to its preservation aspect, also has pedagogical functions and supports national and international research." Another of its functions was, as Eiras-Dias wrote, "to solve the problems of synonymy and homonymy spread over the different wine regions." The extent of this problem and its many causes have already been discussed above. Other examples given by Eiras-Dias are " Castelão (vs. Periquita, vs. Trincadeiro, vs. João de Santarém, vs. Castelão Francês) or Fernão Pires (vs. Maria Gomes)" with debate about the standardisation of their identity causing hot debate in the early 1980s. In his words, the widespread nature of this problem to confusion which, in turn, "had very negative effects on the knowledge and management of the rich viticultural heritage of the country." Steps that led to the founding of CAN began in 1981 with the setting up of the Projecto Nacional de Ampelografia e Sinonímia das Variedades de Videira (National Ampelographic and Synonymous Grapevine Varieties Project or PNASVV). This just predated Portugal's accession to the European Economic Community (a precursor of the European Union (EU) into which on its establishment, EEC was absorbed) and was motivated by a need to be able to operate efficiently within the broader European context. Between PNASVV's formation and the establishment of CAN, a number of regional-based ampelographic projects began, and by the time the national collection was operating, the role and value of ampelography in the wine industry had been established. The integration of CAN with the government's legislative and administrative involvement in the wine industry was shown when CAN's listing became the core of the government's 2000 ordinance list and later revisions including the 2017 "Catálogo Nacional de Variedades de Videira" (National Catalogue of Vine Varieties or NCVV). New information from CAN continues to be provided to the government for the updating of its list, to VIVC and to the EU's certification body, the European Commission (EC). == Scientific research and the establishment of identity == In recent years, genetic testing, DNA profiling and genomics have played a major role in establishing the identity and parentage of grape varieties. Especially Jorge Böhm has to be named when it comes to the scientific research of Portuguese grape varieties, since he's well-known for his success in improving most of the native varieties by mutating new clones with his own plant nursery. But the availability of these services has been limited and largely concentrated on those varieties playing key roles in wine production. This means there is still much work to be done, leaving many varieties still clouded in mystery, and if they are varieties which have passed out of use, it seems unlikely their identities will ever be investigated. One groundbreaking Portuguese research program carried out in the Douro-Porto regions was set up: "…to compare the effectiveness of RAPD (Random Amplified Polymorphic DNA) and ISSR (Inter Simple Sequence Repeat) molecular techniques in the detection of synonyms, homonyms and misnames. RAPD and ISSR analysis enabled the detection of 36 different band patterns, reducing in about 36% the original material. Several accessions grown under different names, between and within collections, were confirmed as the same genotype, namely Gouveio/Verdelho, Sousão Douro/Vinhão and Arinto Oeste/ Pedernã. Similarly, some homonyms/misnames were also identified, namely within Azal Tinto and Rabigato accessions. RAPD and ISSR markers revealed to be adequate molecular techniques for grapevine varieties fingerprinting with advantages over other molecular procedures, contributing for a good management of grapevine collections." The findings from this research illustrated why it has become necessary to sort out the confusion that has been caused and sustained by the use of false and misleading synonyms and homonyms. Regarding, for example, the problem with identifying Sousão (now officially known as Sezão) and Vinhão, the report said: "Results highlight the genetic proximity between Sousão and Vinhão accessions. Sousão is the prime name of a cultivar grown especially in ‘Vinhos Verdes' Region whose cultivar designation was modified to Sezão in the last review of the ‘Portuguese List of Varieties fit for Wine Production'. Vinhão has been reported as the synonym of the