2010 Annual Report
1a.Objectives (from AD-416)
The long-term goals of this project are to develop sugarcane cultivars that are better adapted and more economical to grow and harvest, to meet current and evolving needs of both a sugar and a biofuels industry, and to gain a greater understanding of sugarcane from genetic and physiological perspectives. The objectives are to utilize: (1) a basic breeding program to broaden the genetic base of parental germplasm and increase the adaptability of sugarcane to more temperate climates through the introgression of genes from wild species (Saccharum spontaneum) and related genera of sugarcane, and (2) parental clones from the basic program to develop sugarcane cultivars that are: higher yielding (gross cane and sugar), require fewer inputs, more tolerant to disease and insect pests, and adapted to a broader range of environments than current cultivars (commercial breeding program). To assist in the selection process, trait-specific molecular markers for early sucrose accumulation, sugarcane borer resistance, and cold tolerance will be developed.
1b.Approach (from AD-416)
Included in the basic program’s breeding strategy to increase the genetic diversity of parental clones are: (1) acquisition and maintenance of germplasm from wild species of Saccharum and related genera; (2) characterization of parents and progeny for traits (cold tolerance, stubbling ability, disease resistance, and sugarcane borer resistance) that will increase the adaptation of sugarcane to Louisiana’s temperate climate; (3) utilization of crossing and molecular marker techniques to produce interspecific and intergeneric hybrids containing new sources of disease and insect resistance and cold tolerance; and (4) recombination of progeny through backcrossing to develop parental material containing a concentration of desirable genes for the commercial breeding program. Screening procedures will be developed to determine relative cold tolerance among clonal material in the basic breeding program. In the development of cultivars for sugar and bioenergy, emphasis will be placed on yield components (stalk number, height, and diameter), quality components (sucrose and fiber accumulation), longevity (stubbling ability), harvestability (root anchorage, stalk erectness, and stalk brittleness), hardiness (winter survival, early spring vigor, and stalk freeze tolerance), stress tolerance (droughts, floods, and heavy clay soils), and resistance to stalk boring insects (sugarcane borer and Mexican rice borer) and diseases (smut, rust, leaf scald, mosaic, yellow leaf virus, and ratoon stunting disease). Recurrent selection techniques will be utilized to accelerate the rate of genetic improvement for important traits. In addition, trait-specific markers closely associated with desirable traits such as sucrose accumulation, cold tolerance, and resistance to the sugarcane borer will be developed to assist breeders in eliminating undesirable plants early in the selection process.
Project receives support from the American Sugar Cane League (6410-21000-014-04T) through a Trust Fund Cooperative Agreement, "Improving Sugarcane Production Efficiency," as well as the in-house project 6410-21000-014-00D, "Genetic Improvement of Sugarcane by Conventional and Molecular Approaches." Additional details of research can be found in the reports of the subordinate projects.
Parental lines were placed on crossing carts at the Agricultural Research Service (ARS), Sugarcane Research Unit's (SRU) newly built crossing and photoperiod facilities at Shriever, LA; at the old crossing facilities at Houma, LA; and at Canal Point, FL, in preparation for the fall 2010 crossing season. Last fall, 6,428 commercial sugarane seedlings were advanced to first clonal stage, 736 clones were avanced to the second clonal stage, and 58 clones were were given permanent alphanumeric designations and advanced into multi-location nurseries for yield testing. Regional tests involving five high-fiber clones developed by SRU were harvested in Georgia (2), Louisiana, Mississippi (2), and Texas (2) in partial fulfillment of the requirements of a Department of Energy-dedicated energy crop grant.
A total of 6,448 new seedlings from the sugarcane borer resistance recurrent selection program were set to the field in spring 2010. Two parents from the recurrent selection program for sucrose and five parents from the recurrent selection for sugarcane borer resistance were included on crossing carts at Houma, LA, to continue recurrent selection for increasing sucrose content and resistance to the sugarcane borer.
Last fall, 2,758 selections were made from the basic seedlings planted in 2007, and an additional 312 selections were planted in a second line trial in the fall of 2009. Fifty-one basic clones were selected for inclusion in the 2010 parental population on the breeding carts. Characterization of wild clones for traits of interest, in particular, cold tolerance and disease resistance, is continuing.
In order to produce more markers to be added to the preliminary LCP 85-384 linkage map, 110 new single-sequence repeat (SSR) markers were identified for fingerprinting the LCP 85-384 mapping population. In addition, genetic analysis of several traits (starch and fiber content, plant height, stalk diameter, etc.) and a search for sugar content-related single nucleotide polymorphism (SNP) deoxyribose nucleic acid (DNA) markers are in progress.
Release of Ho 02-113 Energy Cane. An alternative to smut-susceptible L 79-1002, a Type II (high-fiber, low-sucrose) energy cane, is needed. ARS researchers at Houma, Louisiana, developed and released Ho 02-113 as a high-fiber sugarcane cultivar to help meet the needs of a cellulosic biofuels industry primarily interested in sugarcane for its fiber yield. It is anticipated that this cultivar will be increasingly used in the southeastern U.S. in place of L 79-1002, and will yield as well as or better than L 79-1002 in most environments.
Chen, P.-H., Pan, Y.-B., Chen, R.-K., Xu, L.-P., Chen, Y.-Q. 2009. SSR marker-based analysis of genetic relatedness among sugarcane cultivars (Saccharum spp. hybrids) from breeding programs in China and other countries. Sugar Tech. 11(4):347-354.
Hodnett, G.L., Hale, A.L., Packer, D.J., Stelly, D., Da Silva, J., Rooney, W.L. 2010. Elimination of a reproductive barrier facilitates intergeneric hybridization of Sorghum bicolor and Saccharum. Crop Science. 50:1188-1195.
Liang, J., Pan, Y.-B., Li, Y.-R., Fang, F.-X. 2010. Assessment of genetic diversity in Saccharum using SSR markers and capillary electrophoresis. Guihaia. 30(1):106-111.
Tew, T.L., Pan, Y.-B. 2010. Microsatellite (simple sequence repeat) marker-based paternity analysis of a seven-parent sugarcane polycross. Crop Science. 50:1401-1408.