GENETIC IMPROVEMENT OF SUGARCANE BY CONVENTIONAL AND MOLECULAR APPROACHES
Location: Sugarcane Research Unit
Title: Genetic analysis of the sugarcane (Saccharum spp.) cultivar "LCP 85-384".II. identification of QTAs for starch
Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: June 2, 2010
Publication Date: June 16, 2010
Citation: Suman, A., Zhou, M.M., Pan, Y.-B., Kimbeng, C.A. 2010. Genetic analysis of the sugarcane (Saccharum spp.) cultivar "LCP 85-384".II. identification of QTAs for starch [abstract]. Journal of the American Society of Sugar Cane Technologists. 30:138.
Starch in sugarcane juice can impede the extraction of sugar during processing and also
affect the quality of the refined sugar. The problem has been exacerbated by the widespread adoption of green cane harvesting in sugarcane. More starch is usually present in the leaves and young growing portions of the plant than the stalk although judging on a per weight basis a greater proportion of starch is still being contributed by the stalk. The deliberate effort by breeders to broaden the genetic base of sugarcane using Saccharum spontaneum germplasm which is high in starch may also be contributing to the increasing levels of starch in recent cultivars. Alpha-amylase enzymes are used during sugar processing to hydrolyze starch but this practice is expensive and not always efficient.
Developing sugarcane cultivars low in starch content is a more preventative, economical, and sustainable solution. Identifying quantitative trait alleles (QTAs) that associate with starch content and using them in marker-assisted selection during sugarcane improvement would be an efficient way to reduce the starch content. For this purpose, linkage and QTL mapping experiments were conducted in Louisiana using a selfed population of LCP 85-384. Linkage analysis led to the mapping of 717 AFLP, SSR, and TRAP single dose markers onto 108 co-segregating groups (CGs) with a cumulative map length of 5,348 cM. Starch data collected from two replicated field plots of 227 individuals was used to identify QTAs by the composite interval mapping (CIM) method employed in MapQTL v 5.0. A total of 10 QTAs located on eight CGs were detected for starch. These QTAs explained 5.4% to 32.3% of the phenotypic variation with positive additive effects for nine of the ten QTAs. Tentative assignments of QTAs to the parental genomes of LCP 85-384 showed that six QTAs were contributed by both parents, one by the female (CP 77-310) and two by the male (CP 77-407) parent.