Characterization of saccharum species germplasm for starch content

Authors: ZHOU, MARVELOUS - South African Sugar Association; KIMBENG, COLLINS - Louisiana State University; Edme, Serge; Hale, Anna

Submitted to: Journal of Plant Studies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2012
Publication Date: 11/30/2012
Publication URL: http://handle.nal.usda.gov/10113/57145
Citation: Zhou, M., Kimbeng, C., Edme, S.J., Hale, A.L. 2012. Characterization of saccharum species germplasm for starch content. Journal of Plant Studies. 2(1):54-71. DOI: 10.5539/jps.v2n1p54.

Interpretive Summary: To improve sucrose yield, sugarcane breeding programs have to appraise two of its primary components, i.e. cane yield and quality traits (sucrose, purity, pol). One of the hidden quality traits not being taken into consideration is starch, which is viewed as an impurity at the mill. Even though starch is converted to sucrose in the later stages of growth of the sugarcane crop, a high concentration (=250ppm) in the juice at extraction impedes crystallization or recovery and discoloration during the milling and refining processes. Great interest is still devoted to broaden the genetic diversity of sugarcane cultivars by transferring genes from the wild species. By so doing, these wild species will contribute different levels of starch to the progeny cultivars.This study surveyed the sugarcane germplasm collection, comparing wild relatives with cultivars and revealed different oncentrations of starch in the species. The cultivars and S. officinarum species tended to have lower starch content, whereas the sinense and spontaneum species contain higher levels of starch. However, low-starch cytotypes were identified in the wild section of the Saccharum complex, particularly in the spontaneum species which are used extensively to impart disease resistance, stress (cold) tolerance, and tillering capacity. This information is important since there is an utmost interest in using the wild germplasm as parents for breeding cultivars with higher sucrose yield, stress resistance, and bio-energy purposes.

Technical Abstract: The renewed interest in wild Saccharum species germplasm across sugarcane breeding programs has been necessitated by the need to widen the genetic base of breeding populations. Modern sugarcane cultivars were derived from inter-specific hybridization between S. officinarum and S. spontaneum. Very few genotypes were used in the initial hybridization event in 1900s resulting in narrow genetic diversity in modern sugarcane cultivars. Characterization of genotypes in the Saccharum collections would aid its utilization. Starch is considered as an impurity in sugarcane juice because it adversely affects the quantity and quality of sugar products, refining processes and is negatively associated with sucrose content. Therefore knowledge about the starch content of S. spontaneum and other related species would be of interest to breeders. The objective of this study was to characterize the United States of America (USA) sugarcane wild germplasm and related species for starch content. The juice samples used in this study were collected at the United State Department of Agriculture, Agricultural Research Services (USDA-ARS) Sugarcane Research Station at Houma, Louisiana; Canal Point and Miami, Florida germplasm collections. There were highly significant (P<0.001) differences in starch content among species and genotypes within species. There was a non-discrete distribution for starch within the species providing an opportunity for identifying low starch genotypes for use in germplasm enhancement programs. S. spontaneum genotypes produced the greatest variability for starch providing an opportunity for identifying low starch genotypes for use as parents. Cultivated species such as S. officinarum and S. robustum produced low starch indicating that low starch offered advantages for sucrose production. The results of this study would be more useful for parent selection within germplasm for introgression breeding.