2008 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.
The following research supports NP 301: Plant Genetic Resources, Genomics, and Genetic Improvement; Component 3: Genetic Improvement of Crops; Problem Statement 3C: Germplasm Enhancement/Release of Improved Genetic Resources and Varieties.
• A total of 64,300 new commercial-type seedlings were set to the field in spring 2008 from crosses made in the fall 2007. Parental lines, consisting of parents having a history of producing superior progeny and promising experimental varieties based on early stages of testing were placed in Agricultural Research Service’s crossing facilities at Houma, LA, and Canal Point, FL, in preparation for the fall 2008 crossing season. Seed cane nurseries of five high-fiber clones are being increased in AL, AR, GA, and MS in preparation for regional evaluation as dedicated energy crops.
• A total of 5,600 new seedlings from the sugarcane borer resistance recurrent selection program were set to the field in spring 2008. Eight parents from the recurrent selection program for sucrose and 14 parents from the recurrent selection program for sugarcane borer resistance were included on crossing carts at Houma, LA, to continue recurrent selection for increased sucrose content and resistance to the sugarcane borer.
• A total of 23,100 new basic seedlings obtained from crosses of commercial or near commercial sugarcane varieties with wild or related genera of Saccharum were set to the field in spring 2008. Decisions were made based on fall 2007 field data as to which clones should be used as parents in the 2008 crossing season, how many of each parent, and what photoperiod treatment should be given. Characterization of wild clones for traits of interest, especially cold tolerance is continuing.
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