Desenvolvimento de marcadores microssatélites e caracterização da diversidade genética molecular de acessos de alho (Allium sativum L.)

Abstract

Development of microsatellite markers and characterization of molecular genetic diversity among garlic (Allium sativum L.) accessions Garlic is an important crop not only for its culinary attractiveness, but also because of a huge number of medicinal properties. The genetic resources in germplasm require characterization by morphological traits and molecular markers to be effectively used in breeding programs. A novel set of 16 SSR loci specific to garlic were developed. Ten loci were polymorphic, moderate to highly informative, with an average PIC of 0.545 and maximum of 0.851. A total of 151 accessions of garlic from three Brazilian germplam, IAC, ESALQ, and Embrapa, were evaluated for genetic diversity using 10 novel polymorphic SSR loci and other 7 available in the literature. A total of 90 alleles were detected, the average allelic richness was 2.258 alleles per locus and the Shannon index 1.176. The Embrapa collection had the vast majority of private alleles and multi locus genotypes (MLGs). The whole collection was reduced to 65 MLGs. The M strategy were used to define a core collection, 16 accessions were selected with 100% coverage of alleles and minimum redundancy. Overall G ST " was 0.200 and for MLGs, 0.068, indicating a high genetic differentiation within collections, and G IS was-0.195, indicating an excess of heterozygosity, which was expected as garlic is vegetatively propagated. MLGs were structured in two subgroups by Bayesian approach, consistent with the clustering based on genetic distances and PCA. The groups were coherent with the classification of accessions according to phenology (noble and semi-noble). The new SSR loci are tools for future studies of genetic diversity, germplasm conservation, mapping, and associative genetics, and hopefully will shed light on garlic breeding programs.