Genetic Characterization of a Plum Landrace Collection from La Palma, Canary Islands

Abstract

A plum collection located in the island of La Palma, Canary Islands, composed of twenty-nine European and Japanese plums was analyzed using nine simple sequence repeat (SSR) highly polymorphic loci. First, a cytometry flow analysis was performed to determine the ploidy level. Sixteen accessions turned out diploid and thirteen hexaploid. According to morphological characteristics, fourteen of the sixteen diploid accessions were assigned to Prunus salicina, and two accessions to P. cerasifera. All the hexaploid accessions were assigned to P. domestica. The 29 accessions were compared using SSR markers with twenty-two P. domestica accessions maintained at the CITA plum germplasm collection located in Zaragoza, Aragón, Spain. A principal component analysis (PCA) and a clustering approach grouped the accessions according to the assigned species and geographical location, while some synonyms and homonyms were found within La Palma accessions. The two principal components explained 80.3% (67.3% and 13%, respectively) of the total variance. A tree generated with UPGMA hierarchical clustering and Bruvo distance grouped the accessions in two main clusters according to ploidy level and species assignment. The STRUCTURE approach clearly differentiated La Palma diploid accessions and some of the hexaploid accessions from those of the CITA collection. The results obtained could be used for management and conservation purposes of this valuable local plum germplasm.