DEVELOPMENT OF MICROSATELLITE MARKERS FOR FINGERPRINTING AND BREEDING SUBTROPICAL FRUIT TREE SPECIES

Abstract

Microsatellites or SSRs are considered as the marker of choice for fingerprinting and breeding in both plant and animal species. However, in most subtropical fruit tree species no SSR sequences are currently available. In this work, we describe the development of SSR sequences in three subtropical fruit tree species: cherimoya (Annona cherimola Mill.), lychee (Litchi chinensis Sonn.) and mango (Mangifera indica L.). In order to develop the SSRs a genomic library enriched in GA/CT repetitive sequences was performed for each species from DNA of standard cultivars: Fino de Jete for cherimoya, Mauritius for lychee and Tommy Atkins for mango. Microsatellite polymorphism was evaluated in germplasm collections of the three species. For cherimoya, 15 polymorphic SSRs were studied in 40 accessions; for lychee, 12 polymorphic SSRs in 21 accessions; and for mango 15 polymorphic SSRs in 30 accessions. For all the three species studied, the microsatellite enrichment procedure was highly successful since over 70% of the clones studied contained the repetitive sequence in cherimoya and mango and over 50% in lychee. The results are discussed in terms of their implications for fingerprinting, germplasm resources management and breeding of subtropical fruit tree species.