DEVELOPMENT OF MICROSATELLITE MARKERS OF LOQUAT (ERIOBOTRYA JAPONICA) AND ITS APPLICATION ON GENETIC DIVERSITY STUDIES

Loquat (Eriobotrya japonica (Thunb.) Lindl.) was introduced in Europe in the XVIII^th century. First, it was introduced as an ornamental tree. Later, when types with larger fruits were selected, it was grown for its fruits. In Europe, it was grown in regular orchards at the beginning of the XX^th century. To improve loquat cultivation and preserve genetic resources, a collection was established in 1993 at the ‘Instituto Valenciano de Investigaciones Agrarias’ (IVIA), Valencia, Spain. Germplasm management and conservation of genetic resources could be accomplished if detailed characterization of plant material were available. It is important to establish a correct identification of accessions and their genetic relationships.
Among the different techniques available for germplasm studies, molecular markers have some advantages over other marker types. The environment does not affect these markers; they can be detected in all tissues and stages of development; and the number of markers available is very high. Among the different markers, microsatellites or SSR (simple sequence repeats), short sequences containing tandemly repeated copies of 1–6 nucleotide fragments (Rafalski et al., 1996), have been shown as a good source of polymorphism very abundant in eukaryotic genomes. The aim of this study was to develop SSR sequences from loquat and to test its usefulness for genotyping loquat accessions closely related, as a tool for better germplasm management and future cultivar breeding. As a result, eight primers flanking SSRs were obtained. These sequences along with 14 additional from apple were tested in a set of 39 accessions from the germplasm collection at IVIA. Results obtained allowed to discriminate groups of accessions according to their genetic distance.