Phenotypic and Molecular Characterization of a Core Collection of Saccharum spontaneum L. in China

Saccharum spontaneum L. is widely used in developing new sugarcane ( Saccharum spp. hybrids) cultivars due to its ability to transmit high vigor, ratooning ability, and increased tolerance to various biotic and abiotic stresses. Interspecific hybridization helps to broaden the genetic diversity of modern sugarcane cultivars, but there is a continual need to collect and characterize new sources of germplasm. The objective of this study was to evaluate a primary core collection of 92 S. spontaneum genotypes (82 were of Chinese origin) using 29 phenotypic traits and 15 simple sequence repeat markers. There was considerable morphological variation among the S. spontaneum genotypes. Principal component and heatmap analyses indicated that the genotypes could be separated into four groups using two major traits related to yield (stalk length, stalk diameter, and stalk weight) and juice quality traits (juice Brix, juice fiber, juice sucrose, and apparent purity). Genotypes collected from the same geographic location did not cluster together, so geography alone was not a good predictor of genotypic divergence in this collection. Phenotypic trait data alone failed to fully differentiate genotypes, but a combination of phenotypic and molecular data was useful in characterizing the genotypes. The phenotypic and molecular characterization of unexploited S. spontaneum germplasm will facilitate in the identification of potential parents for introgression and identification of high-yielding, disease-resistant cultivars, energy canes, and cultivars suited for abiotic stresses, thereby increasing the economic sustainability of sugarcane.