Genetic diversity of sixteen populations of Philippine Allium sativum L. (garlic)

Garlic has found a wide range of uses of culinary and traditional folk medicine in the Philippines which has encouraged farmers to cultivate different varieties all over the country. However, the genetic diversity of garlic has not been explored by local scientists relative to onion (Allium cepa). Hence, the present study looked into the genetic diversity of Philippine garlic. Sixteen Philippine Allium sativum L. populations of 25 individuals each were examined from the major garlic producing provinces in Luzon (Batangas, Laoag, La union, Mindoro and Nueva Ecija); Visayas (Dumaguete and Silay); and Mindanao (Cagayan de Oro) including one outgroup (Allium ascalonicum) using randomly amplified polymorphic DNA (RAPD). Those garlic populations which are made up of smaller bulbs were classified A while those with relatively larger bulbs were classified B. Twelve RAPD primers were used in the analysis. Three primers such as primers O7, N-3 and I-19 yielded polymorphic bands. The analysis yielded 87 RAPD loci. The data was analyzed using POPGENE vi. 32 followed by the construction of a phylogenetic tree. Genetic diversity as determined with RAPD markers was found among populations. Six clusters were obtained from the phylogenetic tree. The first cluster is composed of six populations (Dumaguete A, Cagayan de Oro A, Vigan A, Batangas B, Mindoro A and Laoag A). The second cluster is also made up of six populations (Cabanatuan A, Silay A, Cabanatuan B, La Union A, Munoz B and Dumaguete B). The third, fourth and fifth clusters are composed of Batangas A, Vigan B and Mindoro B, respectively. The sixth cluster which represented the most distant branch of the tree consisted only of Allium ascalonicum. each cluster represented populations having relatively similar bulb size, number of cloves, aroma and growth rate. Results of this study therefore will serve as a guide for selection breeding to garlic farmers.