'BRS Vitória' - a novel seedless table grape cultivar exhibiting special flavor and tolerance to downy mildew (Plamopara viticola)

CULTIVAR RELEASE

'BRS Vitória' – a novel seedless table grape cultivar exhibiting special flavor and tolerance to downy mildew (Plamopara viticola)

João Dimas Garcia Maia^I; Patricia RitschelI, ^*; Umberto Almeida Camargo^I; Reginaldo Teodoro de Souza^I; Thor Vinicius Martins Fajardo^II; Rosemeire de Léllis Naves^I; César Luís Girardi^II

^IEmbrapa Uva e Vinho, Estação Experimental de Viticultura Tropical, Córrego Barra Bonita, s/nº, CP 241, 15.700-971, Jales, SP, Brazil

^IIEmbrapa Uva e Vinho, Rua Livramento, 515, BairroConceição, 95.700-000, Bento Gonçalves, RS, Brazil

^IIIVino Vitis Consultoria Ltda., Rua Aguinaldo da Silva Leal, nº 141, Apartamento 301, Bairro Cidade Alta, 95.700-000, Bento Gonçalves, RS, Brazil

ABSTRACT

'BRS Vitória' is a novel cultivar of black seedless table grape. Its main traits meet the most important demands from the viticulture segment in Brazil.It is recommended for cultivation in tropical and subtropical areas, with excellent horticultural performance, high bud fecundity and resistance to downy mildew, the most important disease which affects grapevines in Brazil.

Key words: Genetic breeding, adaptation, resistance, fruit quality.

INTRODUCTION

Table grapes of the vinifera-type are mainly produced in subtropical and tropicalBrazilian regions, especially seeded cultivars, such as Itália and its sports(Nachtigal 2003). Consumer markets, mainly international ones, are interestedin growing seedless table grapes. However, several attempts to adapt managementpractices for traditional seedless cultivars introduced in Brazil, such asThompson Seedless, Centennial and Crimson Seedless were unsuccessful (Camargoet al. 1997).

Thus, vinifera-type of seedless table grape cultivars is an important demand of thelocal viticulture industry, especially those aiming at fruit exportation. Inorder to achieve yield quantitative and qualitative standards, novel cultivarswould preferentially be adapted to Brazilian climatic conditions, as well aspresent high natural bud fecundity and quality compatible with theinternational market requirements.

Moreover, cultivars which are tolerant to the main pests and diseases are a common demandfrom the Brazilian grape productive chain. In regions favoring the incidence ofdiseases, such as downy mildew (Plasmopara viticola) and powdery mildew(Uncinula necator), phytosanitary control may consist of up to 30% ofthe production costs (Grigoletti Júnior and Sônego 1997).

'BRS Vitória' is a novel cultivar of black seedless table grape, whose main traitscomply with the most important demands of the segment in Brazil. The cultivaragricultural and yield performance was adequate in trials carried out in theregion of the São Francisco River Valley, located in the Northeast of Brazil, in the Northwestern and Central regions of the state of São Paulo, in theNorthern Paraná, and in the state ofMinas Gerais. It presented excellent horticultural performance in theseregions, high bud fecundity, and tolerance to downy mildew.

Breeding methods

'BRS Vitória' was selected from the cross 'CNPUV 681-29' ['Arkansas 1976' x 'CNPUV147-3' ('Niagara Branca' x 'Vênus')] x 'BRS Linda', made in 2004, at EmbrapaGrape and Wine, Experimental Station of Tropical Viticulture (EVT), in theMunicipality of Jales, State of São Paulo. Three hundred and ninety-nineembryos were rescued from the cross, giving rise to 158 plants, which weregrafted in the vineyards of Embrapa Grape and Wine-EVT. The first harvest took placein August 2007, where the original plant was selected as CNPUV 1167-133 due toits good bud fecundity, raspberry flavor, high sugar content and absence ofseeds. Subsequently, from 2007 to 2012, the horticultural and grape qualitytraits observed in the first harvest were confirmed, along with downy mildewtolerance, which is the main grapevine disease in Brazilian tropical climaticconditions. 'BRS Vitória', labeled Selection 22, was also evaluated from 2010to 2012 in the municipatility of Marialva, North of Paraná, in Tupi Paulista, Northwestern of São Paulo, and in the municipatility of Curaçá, in the state ofBahia (São Francisco River Valley); and from 2011 to 2012, in Indaiatuba andElias Fausto, Center of São Paulo. In 2012, the first harvest occurred in theregion of Jaíba, Minas Gerais, and also in Petrolina, state of Pernambuco, inthe São Francisco River Valley. Grape quality and yield remained stable in theseveral areas where the novel cultivar was assayed.

Main traits and performance

'BRS Vitória' is a vigorous cultivar that contributes to proper vineyard formation in the very first year. It presents wide climate adaptation, expressed by itsexcellent horticultural performance in several regions where it was assayed.The clusters are slightly compact, requiring especial management practices, including the use of growth regulators for elongation and berry thinning with scissors. Yields can be higher than 30 t ha^-1, but 25 to 30 t ha^-1 are recommended for regions with two annual cycles, one vegetative, and theother productive. In regions where it is possible to obtain two annualharvests, it is recommended to limit yields to 16 to 24 t ha^-1 cycle^-1in order to maintain high berry quality. Due to its high level of acidity, harvest is recommended at 19º Brix or higher. At this stage, 'BRS Vitória'berries present the best balance between sugar level and acidity, resulting inan especial pleasant raspberry flavor without astringency. 'BRS Vitória'productive cycle varies from 90 to 135 days, depending on the thermal sum inthe region. The longest cycle was observed in Northern Paraná and in the Centerof São Paulo, whereas the shortest occurred in Curaçá, Bahia, in São FranciscoRiver Valley (Table 1). The thermal requirements for 'BRS Vitória' wereestimated in 1, 511 degree-days from pruning to harvest, and 1, 375 degree-daysfrom bud sprouting to the end of maturation, considering the trough temperatureof 10 ºC.

Fielde valuations to determine the reaction of 'BRS Vitória' to downy mildew [Plasmoparaviticola (Berk. & Curt) Berl] were accomplished in EVT, in January 2008and 2009, with temperature and humidity favorable to the disease incidence. Thereaction to downy mildew was determined by the severity evaluation using agrade scale ranging from 1 to 9 (IPGRI 1997) as follows: 1: highly resistant;3: resistant; 5: moderately resistant; 7: susceptible; 9: highly susceptible.The novel cultivar was graded as resistant (grade 3) in 2008, and highlyresistant (grade 1) in 2009. Therefore, 'BRS Vitória' is conservativelyclassified as resistant (grade 3), the most severe grade attributed to thematerial during the evaluations. The current resistance level means an advancein comparison to that of other seedless cultivars available in the market.

The disease evolution in other genotypes with distinct levels of susceptibility todowny mildew was studied in 2006, from November to December, when the climateconditions in Jales, São Paulo, were extremely favorable to the pathogendevelopment. For genotypes evaluated as resistant (grade 3), as 'BRS Vitória', the initial symptoms were observed 16 days after the arrest of fungicidesapplication (Naves et al. 2008). Thus, it is inferred that the number ofsprayings to control downy mildew in tropical regions can be reduced by the useof 'BRS Vitória' in comparison to the spraying routine program traditionallyadopted for the growing of vinifera grapes. Further studies will be carried outto determine the percentile of reduction.

During the biological assays, a high level of tolerance to leaf blight was alsoobserved. The etiological agent for the disease has not yet been identified.The cultivar is susceptible to leaf-rust (Phakopsora euvitis Ono) andanthracnosis (Elsinoe ampelina (De Bary) Shear) during the rainy seasonand, also, to the attack of fruit fly [Anastrepha fraterculus (Wied.)(Diptera: Tephritidae) and Ceratitis capitata (Wied. 1824)]. InMarialva, Paraná, the occurrence of grape ripe rot [Glomerella cingulata (Ston.) Sapuld & Schrenk] was also observed. Upon the occurrence offavorable conditions to diseases or pests, standard control to vinifera grapesis recommended. The novel cultivar presents good tolerance to berry cracking inthe presence of heavy rainfalls during grape maturation.

According to international commercialization laws, the minimal solid soluble contents mayvary from 14.0 to 17.5 ºBrix, depending on the cultivar and growing conditions.Fruit flavor comes mainly from the balance between sugars and acids (SS/TA ormaturation index). High SS/AT ratio is desirable to consumer markets, and itoffers an adequate fruit evaluation parameter, being more significant than thesugar or acidity contents alone. For table grapes, the recommended ratio shouldbe equal or superior to 20 (Bleinroth 1993). 'BRS Vitória' presents an adequatesugar content, with potential of reaching up to 23 ºBrix (Figure 1).Regarding the high acidity, the harvest is recommended when the grape presentsat least 19 ºBrix, a point of good balance between sugar content andacidity, resulting in a distinguished special raspberry flavor with noastringent taste in the peel.

In post-harvest assays, after 20 days of cold storage (temperature of 0 ºC andrelative humidity of ±95%), followed by three days under shelf-life conditions, rachis' darkening and dehydration were observed. These traits influenced berrylosses, which reached about 2.15%, a level considered low to intermediate.Signs of rot were not observed during storage. Moreover, the balance sugar/aciddid not change, and the berries organoleptic quality was maintained. The SS/TAratio of 'BRS Vitória' was 25.26 after the storage, indicating high potentialfor consumer acceptability (Figure 1).

Phytosanitary status

'BRS Vitória' was screened for the presence of viral infections. In this indexingprocess, the main viruses causing grapevine diseases, such as Leaf roll complexand Rugose Wood Complex were considered. Diagnosis screen was based on RT-PCR(conventional or real-time) or molecular hybridization techniques. These methodologiesare very sensitive and allow the detection of the viral nucleic acid ininfected plants, which are discharged from the development process of producingpropagative material. Thus, exclusively plants identified as healthy were usedas foundation stocks to obtain propagative material for the multiplication of'BRS Vitória'.

Informationon propagative material of the novel cultivar BRS Vitória can be obtained at Embrapa Products and Market, Business Office in Campinas (www.campinas.spm.embrapa.br).

Received 1 August 2013

Accepted 9 April 2014

• Bleinroth EW (1993) Determinação doponto de colheita In Gorgatti Neto A, Gayet JP and Bleinroth EW (eds.) Uvapara exportação: procedimentos de colheita e pós-colheita. EMBRAPA -SPI/FRUPEX, Brasília, p. 20 -21 (Publicações Técnicas, 2).
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• Grigoletti Júnior A and Sônego OR (1997) Principaisdoenças fúngicas da videira no Brasil Embrapa-CNPUV, Bento Gonçalves, 36p.(Circular Técnica, 17).
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• Naves RL, Santana APS, Ritschel PS, Camargo UA, Maia JDG, Henrique CR and Lacerda LA (2008) Avaliação daresistência ao míldio em cultivares e seleções de uvas de mesa apirênicas. TropicalPlant Pathology 33: S201 (Suplement).

Publication Dates

• Publication in this collection
  25 Nov 2014
• Date of issue
  Oct 2014

History

• Accepted
  09 Apr 2014
• Received
  01 Aug 2013