Genetic Variability and Clustering Patterns of Sugarcane (Saccharum spp.) Germplasms with Respect to Sucrose-Related Traits

Fifty-five sugarcane genotypes from around the world were collected and evaluated for potential use as parental material in the USDA ARS Canal Point (CP) sugarcane breeding program in Florida, USA. The genotypes were planted in a trial with four check cultivars on organic soils with four replications, and data were collected for two years [i.e., plant cane (PC) and first ratoon (FR) crops] to assess sucrose-yield-related traits and the cane-yield-related traits in PC. Using a multivariate analysis, variation was observed in all cane—[i.e., stalk weight, stalk population and cane yield] and sugar-yield-related traits [i.e., Brix, Pol, sucrose content and commercial recoverable sucrose (CRS)]. The mean CRS content was greater in the FR crop than the PC crop. Significant variations were attributed to genotype (G), crop cycles (C) and G × C effects. Variations between crop cycles were highly significant for all sucrose yield components, which could complicate the downstream selection of genotypes for sucrose yield. Based on CRS content, genotypes could be grouped into six distinct clusters. Based on plant cane data, cane yield traits (stalk weight, stalk population and cane yield) were used to estimate the breeding values of parents. Of the 55 genotypes, 8 had significantly greater t-BLUP values for cane yield, along with CP 00-1101. Combined sucrose yield traits, (Brix, Pol and sucrose content) from the two crops were used to estimate the breeding values of parents. Of the 55 genotypes, 10 genotypes had significantly greater t-BLUP values for CRS, along with CP 00-1101, CP 96-1252 and CP 01-2390, and can be considered as elite parents in future breeding efforts. These results provide a foundation for the efficient integration of genetic diversity in developing commercial cultivars, with improved sucrose yields, into the CP sugarcane breeding program.