MOLECULAR INSIGHT INTO GREAT HEADED GARLIC DOMESTICATION

Abstract

Allium ampeloprasum evolved as a complex of cyto- and morpho-types widely distributed either in the wild or domesticated range of the Mediterranean regions. The assessment of genetic and hylogenetic relationships between Mediterranean A. ampeloprasum from different ecological niches can provide clues about the origin and domestication of great headed garlic (A . ampeloprasum var Holmense, 2n = 6x = 48). Minisatellite M13, microsatellite (GTG)5 and nucleotide sequence analysis of the internal transcribed spacer region (ITS) were used to assess DNA polymorphism and genetic diversity. M13 and (GTG)5 molecular markers efficiently discriminated A. ampeloprasum gene-pool from A. sativum. Domesticated A. ampeloprasum (great headed garlic, kurrat and leek) clustered consistently within the ampeloprasum group. Allium sativum was found to be closer to A. ampeloprasum than A. fistulosum and A. schoenoprasum. A high number of single point mutations (SNPs) was recorded over the ITS1-2 spacer sequence. Most of great headed garlic SNPs were heterozygous and shared by different specimens of the speciescomplex. All ITS haplotypes were in cis state. It is inferred that heterozygosity played the major role in great headed garlic domestication, adaptation to horticultural conditions along with the increase of yield trait sizes. Thus the switch from a small and wild phenotype to the large and cultivated is mainly associated to heterozygosity rather than to polyploidy