Location: Sugarcane Field StationTitle: Exploring Broad Genetic Resources Available to Sugarcane) Author
Submitted to: Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2012
Publication Date: 10/15/2012
Citation: Wang, J.P., Ayala-Silva, T., Nayak, S.N., Todd, J.R., Villa, A., Glynn, N.C., Yang, X., Glaz, B.S., Comstock, J.C., Kuhn, D.N., Gutierrez, O.A., Gilbert, R. 2012. Exploring Broad Genetic Resources Available to Sugarcane. Symposium on New Paradigms in Sugarcane Research, October 15-17, 2012, Coimbatore, India. p.172. Ed. by R. Viswanathan et al. Interpretive Summary:
Technical Abstract: Sugarcane (Saccharum spp.) is used for sugar and energy. It has a high photosynthetic efficiency and is one of the most productive crops globally. Breeders of energycane and sugarcane have overlapping goals in creating cultivars that resist biotic and abiotic stresses. The World Collection of Sugarcane and Related Grasses (WCSRG) in Miami FL contains approximately 1000 accessions from 45 countries of Saccharum germplasm including 16 different species with S. spontaneum, S. officinarum and S. hybrids the most abundant. This collection prospectively contains many valuable alleles for abiotic stress, disease and sucrose and biomass yields. The aim of this study is to identify useful materials from the collection that can be incorporated into breeding programs. The phenotypic study involved measuring different traits including stalk height, stalk diameter, internode length, stalk color, % flowering, leaf sheath pubescence, inner stalk aerenchyma and pith, Brix, and susceptibility to Sugar Cane Yellow Leaf Virus (SCYLV). The initial results found 23 wild grasses that have a Brix higher than 12, and a combined total of 26.6% of S. officinarum and Saccharum hybrids that are resistant to SCYLV. For the genotypic evaluation, 192 co-dominant microsatellite markers were used initially to screen 8 diverse species from the WCSRG. Of these 76 (39.6%) of the markers were found to be polymorphic with polymorphism information content ranging from 0.22 to 0.89. These polymorphic markers were used to genotype all 1002 accessions individually with approximately 200 alleles scored across all. The phylogenetic analysis revealed that the WCSRG was spread among six major and six minor clustering groups. S. officinurum was scattered in four of the major and four of the minor sub groups indicating that it was the most diverse; whereas, the S. spontaneum the other major species was only spread among two major groups and one minor group and had comparatively less diversity. The Saccharum hybrids were spread among 5 of the groups and S. sinense and S. robustum clustered mostly with S. officinarum revealing a close relationship between these species. Phenotypic and genotypic analyses were used to select a core collection of about 300 accessions that represent >80% of the diversity present in the WCSRG, which will be utilized by breeders in crosses for sugarcane and energycane development to improve yields and resistance to stresses. The core collection may also be used to create an association map for the discovery of desirable alleles or for an enriched association mapping panel. During the next few years, replicate testing of the core collection of yield and other traits will occur at Canal Point, FL and alleles of various candidate genes for target traits will be investigated to identify desirable alleles contributing to these phenotypic traits.