Genetic Relationships among Table-Grape Varieties

Abstract

Genetic relationships among important table-grape varieties were studied through nuclear and chloroplast microsatellite analysis. A total of 376 accessions were genotyped with 25 nuclear microsatellite loci using three multiplex PCRs. The average alleles per locus was 9.96, while the probability of identity was 1.66 x 10⁻²¹. A comparison among genotypes, morphology when needed, and literature data has defined synonyms, homonyms, sports, and mistakes among the plant material. In this study, groups of varieties such as Afus Ali, Ahmeur bou Ahmeur, Chasselas, and Muscat of Alexandria were clarified. A parentage analysis of table-grape cultivars was also carried out using a nonredundant genotype table, which included 273 accessions, accompanied by a thorough search in the literature and chloroplast haplotypes to define the direction of the crosses found. In most cases, the information available about the crosses originating these cultivars was correct, particularly in seedless cultivars. Nevertheless, some cultivars such as Cardinal could not originate from the crosses described or suggested in the literature and alternative parents have been proposed. In other cases, where previous information could not be found or was incomplete, some light has been shed on the genetic origin of some cultivars; for instance, the ancestors of Alphonse Lavallée, Admirable de Courtiller, and Calmeria have been suggested. A mathematical analysis, in the form of likelihood ratios, was done to determine the reliability of the suggested crosses.