Classification of genetic variation in garlic (Allium sativum L.) using SSR markers

Abstract Garlic bulb is an important seasoning ingredient in many of the world's cuisines. However, clonal lineages within this species show a remarkably high degree of phenotypic diversity in bulb size and color. Present study classified the genetic variations of garlic. Seven selected simple sequence repeats (SSRs) revealed a total of 37 alleles across 120 garlic accessions, with an average of seven alleles per locus. The values for observed heterozygosity ranged from 0 to 0.99 (mean = 0.71). The average genetic diversity and polymorphic information content values were 0.586 and 0.518, respectively. Based on the 37 alleles obtained from the seven SSRs, a phylogram was constructed to understand the relationships among the 120 accessions. The garlic accessions were clustered into four main groups (G1-G4) in the phylogram. Group 1 consisted of accessions of 'Aomori', Group 2 consisted of 64 accessions, Group 3 consisted of 25 accessions, and Group 4 consisted of 20 accessions. Our results indicate that genetic diversity is correlated with geographical region. There may have been local selection pressure and differences in adaptability of the garlic to different geographical conditions. All of the tested loci deviated significantly (P < 0.01) from Hardy-Weinberg equilibrium. Thus, a number of disturbances occurred in the garlic population tested, including natural selection. Our findings will help explain the genetic relationships and population structure of garlic accessions