Genetic diversity of the main progenitors of sugarcane from the RIDESA germplasm bank using SSR markers

Abstract

Sugarcane is a crop of economic importance in tropical and subtropical countries, with a high diversity of genetic resources and a long history of genetic manipulation (breeding); however, a reassessment of the genetic variability available to breeders is required in order to further the development of modern varieties. Some methods based on morphological and genealogical data have been used, however, morphological characters are influenced by the environment and genealogical data can result in distorted information. On the other hand, SSR molecular markers can reliably distinguish between closely related individuals, a property particularly useful in crops that have a narrow genetic base. The aim of this study was to evaluate the genetic diversity of the main progenitors of sugarcane from the germplasm bank of RIDESA, using SSR markers. Forty-seven varieties were analyzed and the results showed a total of 124 polymorphic alleles with sizes ranging from 81 to 340bp. Of these, 22 were classified as rare alleles and twelve others were considered common. The microsatellites used, showed elevated values for polymorphism and discriminatory power, as well as low indices of genetic identity. The average similarities observed between the main progenitors from RIDESA were low, probably as a consequence of high levels of ploidy and heterozygosity for this crop. Moreover, the cluster analysis showed a complex overall structure, as there was no tendency to form groups with varieties obtained from the same hybridization or parent.