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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

2017 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:
Economic losses caused by sugarcane diseases, especially sugarcane brown and orange rusts, mosaic, ratoon stunting disease (RSD), smut, and leaf scald, are substantial. Thus, the Canal Point (CP) Cultivar Development Programs (CP programs) screen its germplasm for resistance to these diseases. Data are obtained in natural infection and inoculated trials ensuring that resistant or disease tolerant clones are advanced and released from the program. Because pathogenic changes occur over time, developing resistance is continuous in the CP programs. Total of 18 CP cultivars were released in the last 5 years and all of these cultivars are resistant or tolerant to most diseases.


4. Accomplishments
1. Since 2012, the Canal Point (CP) Cultivar Development Programs have been requiring the elimination of susceptible clones. Thus, all susceptible clones in the seedling, Stage I and Stage II are eliminated if exhibiting disease symptoms based on natural infection. In two CP Cultivar Development Programs (Organic-soil CP program and Sand-soil CP program), clones in both the muck and sand programs were screened annually in inoculation tests at Stage III (135 clones), Stage III increase (40 clones) and Stage IV (13 clones) for their disease reactions to ratoon stunt, smut, brown rust, orange rust, leaf scald and mosaic. All clones with unacceptable susceptibility levels were discarded. Thus, the Canal Point (CP) sugarcane cultivars released in the last five years are resistant or tolerant to most diseases.

2. In 2012, a total of five Canal Point (CP) cultivars (CP05-1526, CPCL02-6848, CPCL05-1102, CPCL05-1201, CPCL05-1791) were released (2 for both muck and sand soils, 2 for muck only and 1 for sand only, respectively) by scientists in the ARS Canal Point, Florida, with collaboration of University of Florida and Florida Sugar Cane League. These resistant cultivars have contributed greatly to the Florida sugarcane sustainable production. In 2013 and 2014, three new CP cultivars were released. CP06-2400 was released in 2013 and mainly for muck soils. CP06-2042 (for both muck and sand) and CP07-2137 (for sand soils only) were released in 2014. In 2015, a total of seven CP cultivars (CP07-2320, CP08-1110, CP06-2425, CP06-2495, CP06-3130, CP06-2964, and CP07-1313) were released by the Florida sugarcane variety committee. CP07-2320 is for both muck and sand soils; the rest of them are for sand soils only. In 2016, a total of eight clones were released (1 for both muck and sand soils, 2 for muck only and 5 for sand only). Overall, these disease resistant CP cultivars have contributed to the Florida sugarcane industry and will allow Florida sugarcane growers to continue to economically grow sugarcane and produce approximately 20% of the sugar consumed in the United States and provide growers an effective means of controlling diseases.

3. Sugarcane yellow leaf disease is caused by Sugar Cane Yellow Leaf Virus and aphids transmit the virus. Unfortunately, there is not an efficient screening method to determine resistance consequently a molecular marker for resistance will be most beneficial. A typical population (X02-724) has been evaluated for its yellow leaf reaction for 4 years based on natural field exposure to infection by scientists in the ARS Canal Point, Florida. The phenotypic disease data obtained from this segregating population are important for future marker development and screening diseases.


Review Publications
Singh, M., Comstock, J.C., Davidson, W., Gordon, V.S., Sandhu, H., McCord, P.H., Zhao, D., Sood, S.G., Baltazar, M., McCorkle, K.M. 2017. Registration of ‘CP 06-2425’, ‘CP 06-2495’, ‘CP 06-2964’, ‘CP 06-3103’, and ‘CP 07-1313’ sugarcane for sand soils in Florida. Journal of Plant Registrations. 11:143-151.
Zhao, D., Comstock, J.C., Sighn, M., Davidson, W., Abbott, T.E., Gordon, V.S., Sandhu, H., McCord, P.H., Sood, S.G., Baltazar, M. 2017. Registration of ‘CP 08-1110’ sugarcane. Journal of Plant Registrations. 11:135-142.
Davidson, W., Sandhu, H., McCord, P.H., Comstock, J.C., Edme, S.J., Zhao, D., Glaz, B.S., Sood, S.G., Glynn, N.C., Gilbert, R., Singh, M., Baltazar, M., McCorkle, K.M. 2017. Registration of ‘CP 06-2042’ sugarcane. Journal of Plant Registrations. 11:121-128.
Gordon, V.S., Comstock, J.C., Sandhu, H.H., Gilbert, R.A., Korndorfer, P., El-Hout, N., Arundale, R., Sood, S.G. 2016. Registration of 'UFCP 84-1047' sugarcane for use as a biofuel feedstock. Journal of Plant Registrations. 10:251-257.