Molecular marker-based characterization of ecuadorian dry forest tamarind plus trees

espanolPara aumentar el potencial del tamarindo como especie domesticada con valor economico es importante caracterizar la variabilidad en Ecuador con propositos de mejoramiento. Nuestro objetivo fue investigar la diversidad genetica de 32 arboles elite de tamarindo utilizando marcadores de secuencia inter-simple repetida (ISSR). Se examinaron 84 loci con 12 marcadores, con un numero promedio de 4,42 loci per primer; 8 loci (9,52 %) fueron monomorficos y 76 (90,48 %) polimorficos, revelando variabilidad genetica entre individuos. El contenido de informacion polimorfica (PIC) oscilo entre 0,29 (ISSR_808) y 0,93 (ISSR_HB12), mientras que el indice de marcador fluctuo entre 26,4 (ISSR_814) y 62,5 (ISSR_17899A). ISSR_HB11, ISSR_836, ISSR_842, ISSR_848, ISSR_860, ISSR_17899A e ISSR_17899B fueron utiles para discriminar accesiones segun sus CIPs. El analisis de conglomerados de Ward formo dos grupos principales y cinco subgrupos con 46 % de similitud segun la distancia de Jaccard. Genotipos de Loja, Manabi y Guayas se aglomeraron en un grupo; mientras que solo accesiones de Manabi quedaron en el otro, indicando mayor diversidad en la ultima provincia. Los genotipos T1-ECUM-001 y T1-ECUM-002 presentaron 76 % similitud, mientras T1-ECUM-008, T1-ECUM-010, T1-ECUM-012, T1-ECUM-017 y T1-ECUM-018 compartieron 60 %. Todos los materiales de Loja se agruparon con 65 % de similitud. Otros genotipos se concentraron con similitud de 54 %. El coeficiente de correlacion cofenetica (0,634) mostro buen ajuste entre la matriz de datos y los resultados del dendrograma. Se encontro un grado razonable de diversidad entre los genotipos de tamarindo potencialmente util para seleccionar arboles elite para propagacion clonal asi como para identificar progenitores diversos para programas de hibridacion. EnglishTo improve the potential of tamarind as an economically valued domesticated species it is important to characterize its variability in Ecuador for breeding purposes. Our aim was to investigate the genetic diversity of 32 tamarind plus trees using inter-simple sequence repeat (ISSR) markers. Eighty four loci were examined using 12 markers, with a mean number of 4.42 loci per primer; 8 loci (9.52 %) were monomorphic and 76 (90.48 %) polymorphic, revealing genetic variability among the individuals. Polymorphic information content (PIC) values varied from 0.29 (ISSR_808) to 0.93 (ISSR_HB12), whereas the marker index ranged from to 26.4 (ISSR_814) to 62.5 (ISSR_17899A). Primers ISSR_HB11, ISSR_836, ISSR_842, ISSR_848, ISSR_860, ISSR_17899A and ISSR_17899B were useful to discriminate the grouping of the accessions according to their PIC values. Ward cluster analysis grouped accessions into two major groups with five subgroups with 46 % similarity according to Jaccard distance. The genotypes from Loja, Manabi and Guayas provinces were grouped in the first cluster; while only individuals from Manabi located in the other group, indicating major diversity in the latter province. Genotypes T1-ECUM-001 and T1-ECUM-002 presented 76 % similarity, while T1-ECUM-008, T1-ECUM-010, T1-ECUM-012, T1-ECUM-017 and T1-ECUM-018 shared 60 %. All materials from Loja grouped with 65 % similarity. Other genotypes clustered with similarity of 54 %. The cophenetic correlation coefficient (0.634) showed a good fit between the data matrix and the dendrogram results. A reasonable degree of diversity was found among tamarind genotypes potentially useful to select plus trees for clonal propagation as well as to identify diverse parents for hybridization programs.