Assessing the identity of the variety 'Pedro Giménez' grown in Argentina through the use of microsatellite markers

Pedro Giménez' is a white criolla variety cropped in Argentina, mainly in Mendoza and San Juan, being the most planted white variety destined for wine making in the country. Its origin remains unknown, as well as its relationship with Spanish variety 'Pedro Ximénez', mostly grown in Jerez, Spain. Previous works have probed that most of Criollas varieties existing in America at the moment, are the offspring of 'Muscat of Alexandria' x 'Criolla Chica'. The aim of the present work was to compare 'Pedro Giménez' with the Spanish variety 'Pedro Ximénez', and to establish its degree of relatedness to 'Muscat of Alexandria' and 'Criolla Chica'. Therefore we used a set of 18 nuclear SSR loci and 3 chloroplast SSR loci. 'Pedro Giménez' shared only 38% of the alleles under analysis with 'Pedro Ximénez', indicating that they are indeed two different varieties. In all 18 polymorphic nuclear SSR loci 'Pedro Giménez' shared 50% of its alleles with 'Muscat of Alexandria', while the other 50% of the alleles present in 'Pedro Giménez' were also present in 'Criolla Chica'. This data, along with those from the chloroplast SSR analysis, strongly suggest that 'Pedro Giménez' is the progeny of 'Muscat of Alexandria' x 'Criolla Chica', being the latest one the most likely female progenitor.

Genetic diversity among alfalfa genotypes (Medicago sativa L.) of non-dormant cultivars using SSR markers and agronomic traits

The aim of this study was to assess genetic diversity among 40 alfalfa (Medicago sativa L.) genotypes of different non-dormant (FD=8) cultivars. Biomass yield, regrowth speed and reaction to spring black stem, lepto leaf spot, and rust were evaluated. Analyses of variances were performed using a mixed model to examine the agronomic variation among individuals. A principal component analysis on standardized agronomic data was performed. Agronomic data were also used to calculate Gower's distance and UPGMA algorithm. For the molecular analysis, six SSR markers were evaluated and 84 alleles were identified. The genetic distance was estimated using standard Nei's distance. Average standard genetic diversity was 0.843, indicating a high degree of variability among genotypes. Finally, a generalized procrustes analysis was performed to calculate the correlation between molecular and agronomic distance, indicating a 65.4% of consensus. This value is likely related to the low number of individuals included in the study, which might have underestimated the real phenotypic variability among genotypes. Despite the low number of individuals and SSR markers analyzed, this study provides a baseline for future diversity studies to identify genetically distant alfalfa individuals or cultivars.