Genetic redundancy among durum wheat accessions as assessed by SSRs and endosperm proteins

Abstract

Reducing duplication in ex-situ collections is complicated and requires good quality genetic markers. This study was conducted to assess the value of endosperm proteins and SSRs for validation of potential duplicates and monitoring intra-accession variability. Fifty durum wheat (Triticum turgidum ssp. durum) accessions grouped in 23 potential duplicates, and previously characterised for 30 agro-morphological traits, were analysed for gliadin and high molecular weight glutenin (HMWG) subunit alleles, total protein, and 24 SSRs, covering a wide genome area. Similarity and dissimilarity matrices were generated based on protein and SSRs alleles. For heterogeneous accessions at gliadins the percent pattern homology (PH) between gliadin patterns and the Nei's coefficient of genetic identity (I) were computed. Eighteen duplicates identical for proteins showed none or less than 3 unshared SSRs alleles. For heterogeneous accessions PH and I values lower than 80 identified clearly off-types with more than 3 SSRs unshared. Only those biotypes differing in no more than one protein-coding locus were confirmed with SSRs. A good concordance among proteins, morphological traits, and SSR were detected. However, the discrepancy in similarity detected in some cases showed that it is advisable to evaluate redundancy through distinct approaches. The analysis in proteins together with SSRs data are very useful to identify duplicates, biotypes, close related genotypes, and contaminations.Additional key words: cereals; duplicates; ex-situ collections; molecular data; prolamins. ResumenEvaluación de la redundancia genética con microsatellites y proteínas del endospermo en accesiones de trigo duro Reducir la existencia de duplicados en las colecciones ex-situ es una tarea complicada que require el uso de buenos marcadores geneticos. En el presente trabajo, se evalúa el valor de las proteínas del endospermo y de los SSRs para la identificación de duplicados potenciales y el análisis de la variabilidad dentro de las accesiones. Se han seleccionado 50 accesiones de trigo duro (Triticum turgidum ssp. durum), agrupadas en 23 duplicados potenciales y previamente caracterizadas para 39 caracteres agro-morfológicos. Se ha analizado su composición en proteina total, alelos de gluteninas de alto peso molecular (HMWG) y 24 SSRs, cubriendo gran parte del genoma. Con los datos de los alelos de proteínas y SSRs se han generado matrices de similitud y disimilitud. En las accesiones heterogéneas para gliadinas se ha calculado el porcentaje de homología entre los patrones de gliadinas (PH) y el coeficiente de identidad genética de Nei (I). Los 18 duplicados idénticos en su composición en proteínas mostraron menos de 3 alelos SSRs diferentes. En las accesiones heterogéneas, los valores de PH e I menores de 80 identificaron a los individuos fuera de tipo, con más de 3 alelos SSRs diferentes. Solamente aquellos biotipos que diferían en no más de 1 locus proteíco se confirmaron con SSRs. Se ha detectado una buena concordancia entre los datos de prote...

DNA fingerprinting based on simple sequence repeat (SSR) markers in sugarcane clones from the breeding program RIDESA

“…Determining the genetic profile of varieties has great importance in breeding, allowing for the identification of duplicates in the germplasm bank and the organization of crosses leads to a better breeding result (Ruiz et al, 2011). In addition, it enables the establishment of criteria for the protection of varieties, with the genetic profile included as a unique feature of each access.…”