Abstract:

In this study,we revealed the genetic diversity,principal coordinate analysis and population structure analysis of 676 garlic accessions from all over the word by using 24 pairs of selected primers. The results indicate that a total of 124 polymorphic sites were detected,with an average of 5.17 alleles,an average of 1.77 for Nei's diversity index and 0.62 for Shannon information index. The mean values of observed and expected heterozygosity were 0.33 and 0.34,respectively. The method of neighbor-joining clustered all the accessions into four groups,group Ⅰ included 186 accessions,most of which were derived from middle and high latitudes of Asia,group Ⅱ included 205 accessions,most of which were derived from Europe,Central Asia and North America,group Ⅲ included 132 accessions,most of which were half-bolting types from Asia,group Ⅳ included 153 accessions,most of which were derived from lower latitudes of Asia. The garlic population was divided into three groups by principal coordinate analysis,accessions from lower latitude of Asia gathered in group Ⅰ and group,accessions from middle and high latitudes of Asia,Europe,North America area gathered in group Ⅱ. Population structure analysis divided the germplasm into four groups,which were similar to cluster analysis,there was gene exchange among different garlic groups. The genetic diversity and Shannon's diversity information index of germplasm resources from Europe,Central Asia and North America were the highest,which were 0.3213 and 0.5933,respectively,indicating that this population had rich genetic diversity. The method of neighbor-joining cluster analysis and population genetic structure analysis divided 382 Chinese resources into four groups,mainly from North China,South China,Mongol Xinjiang and Southwest China,respectively. The germplasm of North and South China was distributed at both ends of PC1 by principal coordinate analysis,showing a distant phylogenetic relationship. The results can provide scientific basis for the identification and evaluation of garlic germplasm and the breeding of superior garlic varieties.

Key words: garlic, SSRseq, population structure, genetic diversity