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ARS Home » Southeast Area » Canal Point, Florida » Sugarcane Field Station » Research » Research Project #422807

Research Project: MANAGEMENT OF DISEASES OF SACCHARUM HYBRIDS THROUGH DEVELOPMENT AND EVALUATION OF RESISTANT GERMPLASM

Location: Sugarcane Field Station

2015 Annual Report


1a. Objectives (from AD-416):
1. Optimize assessment technologies for evaluating sugarcane disease resistance. 2. Characterize biological and molecular variation of endemic and emerging sugarcane pathogens. 3. Evaluate sugarcane and energy cane clones to identify resistant germplasm to diseases that are economically important and threatening in the varietal development programs. 4. Identify parental clones and characterize populations that will enhance the development of resistant cultivars for commercial release.


1b. Approach (from AD-416):
1. For brown rust, seedlings of three crosses that vary in the proportion of brown rust susceptible progeny will be in inoculation experiments to evaluate conditions that have promoted infection using older plants. 2. Sentinel plots of susceptible cultivars that were previously rated resistant and resistant commercial cultivars will be planted with two replications in each of the ten Stage IV locations annually (the test has a three crop cycle). Spores will be collected separately from each variety of this test and inoculated to a duplicate set of standard cultivars (of all cultivars that spores were collected from plus B4362). Differences in rust reaction based on sporulation between the isolates on each cultivar will be recorded and verified by repeating the inoculation test. For orange rust, similar experiments as described above will be conducted once handling procedures are developed that eliminate problems with spore viability. For other diseases/pathogens, clones will be surveyed at two month intervals on the Sugarcane Field Station and in 6 growers’ fields for outbreaks of both exotic and endemic diseases. Once something new is suspected the pathogen (pathogenic race) will be identified and similar experiments as that described for brown rust above will be conducted. 3. Sugarcane clones in the cultivar development programs for sucrose and bio-energy will be screened for their disease reactions to the major pathogens in artificial inoculation tests and ratings will be determined based on incidence and severity of disease. 4. Sugarcane progeny of selected families, parental clones in the Canal Point (CP) Cultivar Development Program and clones in other populations will be inoculated using standard procedures and disease resistant individuals will be identified.


3. Progress Report:
Sugarcane diseases cause economic losses; thus, the Cultivar Development Program screens its germplasm for resistance. Both natural infection and artificial inoculation data are obtained to ensure only the most resistant clones are advanced and released from the program. Unfortunately, pathogenic changes have evolved causing the loss of some clones that were previously classified as resistant. However, resistant varieties have been released.


4. Accomplishments
1. Elimination of susceptible clones of sugarcane is essential in the Cultivar Development Program. Thus, all the clones in the cultivar development program were screened in Stage II (1500) Stage III (135) and Stage IV (18) in the variety development program for organic soil (muck) were screened for their disease reactions to ratoon stunt, smut, brown rust, orange rust, leaf scald and mosaic. Similarly, clones for sand soil were screened. Clones with unacceptable susceptibility levels were discarded. Seven clones were released and these cultivars will allow Florida sugarcane growers to continue to economically grow sugarcane and produce approximately 20% of the sugar consumed in the United States. Resistant sugarcane cultivars provide growers an effective means of controlling diseases.


Review Publications
Leon, R.G., Gilbert, R.A., Comstock, J.C. 2014. Energycane (Saccharum spp. x Saccharum spontaneum L.) Biomass Production, Reproduction, and Weed Risk Assessment Scoring in the Humid Tropics and Subtropics. Agronomy Journal. 107(1):323-329. doi: 10.2134/agronj14.0388.
Sandhu, H.S., Gilbert, R.A., Comstock, J.C., Gordon, V.S., Korndorfer, P., El-Hout, N., Arundale, R. 2015. Registration of 'UFCP 74-1010' Sugarcane. Journal of Plant Registrations. 9(2):179-184. doi: 10.3198/jpc2014.06.0042crc.