ABSTRACT: Genetically diverse interspecific hybrids of Vitis were selected for resistance to Pratylenchus brachyurus. Three segregating populations with 57 hybrid crosses were evaluated. The parents included Vitis romanetiiC166-043 × 07355-075, 06354-047 × Cereza and 06354-047 × Nocera, selected from the germplasm bank at the University of California, Davis, the United States. The experiment was arranged in a randomized block design, with three replications and three plants per plot. Root mass, nematodes per gram of root and reproduction factor were determined and used as quantitative variables; 16 multi categoric descriptors were also evaluated. The traits were analyzed using the Ward-Modified Location Model procedure (Ward-MLM) for the composition of genotype groups. Genetic parameters and prediction of genetic values by Restricted Maximum Likelihood / Best Linear Unbiased Prediction (REML / BLUP) were assessed. The Ward-MLM classification strategy supported the formation of three homogeneous groups. Group I comprised 13 hybrids; Group II, 26 hybrids; and Group III, 18 hybrids. Groups II and III contained hybrids resistant to P. brachyurus. High broad sense heritability values were found for root mass, reproduction factor and nematodes per gram of root, which provided genetic gain and allowed selection of resistant genotypes available for cloning, since the total genetic variance occurred due to the dominance effects. Of the 57 genotypes assessed, those with the lowest genotypic values for reproduction factor were selected as resistant, including: CH3.2, CH3.23, CH3.8, CH3.37, CH3.38, CH3.41, CH3.36, CH2.1, CH2.7, CH1.1, CH1.3 and CH1.2.

ABSTRACT Genomic selection (GS) has recently been proposed as a new selection strategy which represents an innovative paradigm in crop improvement, now widely adopted in animal breeding. Genomic selection relies on phenotyping and high-density genotyping of a sufficiently large and representative sample of the target breeding population, so that the majority of loci that regulate a quantitative trait are in linkage disequilibrium with one or more molecular markers and can thus be captured by selection. In this study we address genomic selection in a practical fruit breeding context applying it to a breeding population of table grape obtained from a cross between the hybrid genotype D8909-15 (Vitis rupestris × Vitis arizonica/girdiana), which is resistant to dagger nematode and Pierce’s disease (PD), and ‘B90-116’, a susceptible Vitis vinifera cultivar with desirable fruit characteristics. Our aim was to enhance the knowledge on the genomic variation of agronomical traits in table grape populations for future use in marker-assisted selection (MAS) and GS, by discovering a set of molecular markers associated with genomic regions involved in this variation. A number of Quantitative Trait Loci (QTL) were discovered but this method is inaccurate and the genetic architecture of the studied population was better captured by the BLasso method of genomic selection, which allowed for efficient inference about the genetic contribution of the various marker loci. The technology of genomic selection afforded greater efficiency than QTL analysis and can be very useful in speeding up the selection procedures for agronomic traits in table grapes.

Dez cultivares de videira foram genotipadas com oito locos microssatélites a fim de confirmar a sua identidade e caracterizar sua diversidade genética. Destas, o perfil de nove cultivares foram idênticos aos da base de dados e o de 'Magoon' foi idêntico a 'Regale' deste estudo e de 'Regale' da base de dados da Universidade da Califórnia (Davis), indicando um provável erro de plantio. O número de alelos variou de 5 (VVM5) a 9 (VVMD31). A heterozigosidade observada variou de 37,14 (VVMD5) a 97,14% (VVMD27), sem diferenças significativas em relação aos valores esperados para todos os locos, exceto para VVMD5. Os valores de conteúdo de informação polimórfica (PIC) foram superiores a 0,25 em mais de 85% dos locos analisados, sendo que VVMD31 apresentou-se como o mais informativo. Por meio da análise de agrupamento UPGMA foi possível separar as cultivares em 2 grupos distintos. Dentro de cada grupo, as cultivares mais divergentes foram 'Bountiful' (V. rotundifolia) e 'Goethe' (V. labrusca), que também apresentaram o maior número de alelos privados, 4 e 7, respectivamente. Quando comparados os dois grupos, as cultivares mais divergentes foram 'Bountiful' e 'Bordo', com a maior distância de Nei. Foi evidenciado que há variabilidade genética suficiente nas cultivares utilizadas neste estudo para subsidiar programas de melhoramento genético.

Ten grapevine cultivars were genotyped at eight microsatellite loci to characterize their identity and genetic diversity. Of these, nine cultivar profiles matched with those of databases and 'Magoon' matched with 'Regale' in the present study and 'Regale' in the University of California (Davis) database, implicating a likely error in planting. The number of alleles ranged from 5 (VVM5) to 9 (VVMD31), and the observed heterozygosity ranged from 37.14 (VVMD5) to 97.14% (VVMD27), with no significant differences in relation to the expected values for any of the loci, with the exception of VVMD5. The polymorphism information content values were observed to be above 0.25 in more than 85% of the loci analyzed, and VVMD31 was the most informative. The UPGMA analysis clustered the cultivars into two distinct groups. Within each group, the most divergent cultivars were 'Bountiful' (V. rotundifolia) and 'Goethe' (V. labrusca), also exhibiting the largest number of private alleles, 4 and 7, respectively. When comparing the two groups, the most divergent accessions were 'Bountiful' and 'Bordo', with the highest Nei distance. It was demonstrated that there is sufficient genetic variability in the cultivars used in this study to support breeding programs.