Location: Sugarcane Field Station
2022 Annual Report
Objectives
1. Identify pathogenic variation in sugarcane pathogens that are endemic and emerging within the United States. 1. A: Identify variation in sugarcane pathogens that are endemic and detect emerging pathogens in Florida. 1. B: Characterization of endophytes of sugarcane during disease development. 2. Screen germplasms of sugarcane and related grasses for resistance to major diseases such as brown rust, orange rust, leaf scald, sugarcane mosaic, smut, and ratoon stunting diseases. 2. A: Screen sugarcane clones for brown rust, orange rust, leaf scald, sugarcane mosaic, smut, and ratoon stunting diseases. 2. B: Molecular approach to develop disease-resistant cultivars
Approach
Natural infections of sugarcane clones in Stage IV, small and large seed increases at ten commercial production locations across the sugarcane production region in FL will be surveyed in the spring and fall for all the economically important diseases. Unusual disease symptoms or disease outbreaks on previously disease-resistant cultivars will be investigated as possible emerging pathogens or new pathogenic races\strains of an endemic pathogen. Studies by light, confocal laser scanning microscope, or/and electron microscopy will be conducted to determine if there is any cytological structural difference in the interaction between orange rust race and host. Microbial diversity of a sugarcane variety susceptible to leaf scald and mosaic caused by Xanthomonas albilineans and Sugarcane mosaic virus, respectively. Sugarcane clones in the Stage 3 increase and Stage 4 of the Canal Point Sugarcane Cultivar Development Program will be screened for their reactions to leaf scald, mosaic, ratoon stunt, and smut diseases in artificial inoculation tests. Incidence of Sugarcane yellow leaf virus and ratoon stunt will be determined in the sugarcane clones of small and large seed increases to provide stakeholder status of these diseases in seed canes. Genome-wide markers for mapping genes controlling particular disease resistance in sugarcane will allow finding candidate resistance genes and gene variations. A database to select the reliable and low dosage SNPs for R-gene; SNP array development to realize high throughput genotyping of mapping populations for rapid identification of markers linked to disease resistance in sugarcane; identify haplotype variation associated with diseases (Brown and orange rust, Leaf scald, Smut, and Ratoon Stunting Disease) resistance.
Progress Report
This report documents progress for the Project 6030-22000-012-000D Understanding and Incorporating Disease Resistance into New Sugarcane Cultivars, which started March 2022 and continues research from Project 6030-22000-011-Identification of Resistant Germplasm and Markers Associated with Resistance to Major Diseases of Sugarcane. Pathogenic variability in endemic pathogens and emerging pathogens could cause tremendous losses to sugarcane production. Therefore, monitoring and evaluating pathogens' variability is essential for the sugarcane industry. ARS researchers tested the variation in leaf scald pathogen isolates by inoculation tests on three replications of a set of the cultivars CP 16-1488 (Highly Susceptible), CPCL 13-4079 (Susceptible), CP 80-1743 (moderately susceptible), CP 13-1223 (moderately resistant) and CP 72-2086 (Resistant) by the decapitation method. Inoculated four-month-old plants with a bacterial suspension or water (for a negative control). Rated the disease after two weeks and will continue until 12 weeks after inoculations. The cooperative plant-microbe interactions can promote the recruitment of beneficial microorganisms and limit the development of pathogens. Plant microbiota may thus constitute a key factor to address the challenges of plant health by predicting future plant defense and crop resistance. A trial with four replicates of CP 14-1488 was planted and inoculated with mosaic and leaf scald pathogens. Economic losses caused by brown and orange rusts, leaf scald, sugarcane mosaic virus, ratoon stunt disease (RSD), and smut are substantial. Thus, the Canal Point Sugarcane Breeding and Cultivar Development Programs (CP programs) screen sugarcane germplasm for resistance to these diseases. ARS researchers obtained disease reaction data of these diseases by natural infection and inoculated trials ensuring the development of disease resistant tolerant clones. Because pathogenic changes occur over time, selecting disease-resistant cultivars is an ongoing process in the CP programs. Obtained disease reaction data for clones in the CP sugarcane cultivar development program for 1500 clones in Stage II for brown and orange rust, for 86 clones in Stage III increase (CP 18 Series) for mosaic, and smut, and for 26 clones in Stage IV (CP 17 Series) for mosaic and smut. Advanced clones with acceptable resistance levels to later stages of the programs. Released high yielding and disease-resistant or tolerant cultivars for commercial cultivation. Sugarcane germplasm collections at Canal Point contain great diversity and probably a large number of valuable alleles for disease resistance. For breeders to utilize these germplasm accessions, it will be very informative to determine all the resistance gene and/or allele versions within the accessions of the sugarcane germplasm collections. ARS researchers selected 150 CP breeding parental lines frequently used in the last 10 years for crossing and 40 wild type accessions.
Accomplishments
1. Disease resistant cultivars for commercial production. Sugarcane is a genetically complex polyploid clonally propagated and has multi-year crop cycles. The major diseases in Florida are brown and orange rusts, leaf scald, sugarcane mosaic virus, ratoon stunt disease (RSD), and smut. These diseases could cause 10 to 60% yield losses in the susceptible cultivars under stressed conditions. Therefore, the local sugarcane industry must cultivate high-yielding disease-resistant cultivars for sustainable and profitable sugar production. Sugarcane growers in Florida rely entirely on the improved Canal Point (CP) sugarcane cultivars. The development of the disease resistant cultivars starts with the crossing and subsequent selection of disease resistant clones at every stage of the development and takes more than ten years. In June 2022, Florida Sugarcane Variety Committee released three new cultivars that are resistant and tolerant to the diseases mentioned earlier, CP 15-1407, CP 15-2516, and CP 15-2258, developed by the ARS scientists at Canal Point, in collaboration with the University of Florida and the Florida Sugar Cane League. The CP cultivars have significantly contributed to sustainable sugarcane production in Florida and provided approximately 20% of the sugar consumed in the United States.
Review Publications
Sood, S.G., Momotaz, A., Davidson, W.R., Islam, M.S., Sandhu, H.S., Zhao, D., Baltazar, M., Gordon, V.S., Mccord, P.H., Coto Arbelo, O. 2022. Registration of ‘CP 12-1753’ sugarcane. Journal of Plant Registrations. 16:44-53. https://doi.org/10.1002/plr2.20178.
Islam, M.S., Sandhu, H.S., Zhao, D., Sood, S.G., Momotaz, A., Davidson, W.R., Baltazar, M., Gordon, V.S., Mcccord, P.H., Coto Arbelo, O. 2022. Registration of ‘CP 13-1223’ sugarcane for Florida organic soils. Journal of Plant Registrations. 16:54-63. https://doi.org/10.1002/plr2.20186.
Momotaz, A., Davidson, W.R., Islam, M.S., Sandhu, H.S., Zhao, D., Sood, S.G., Baltazar, M., Coto Arbelo, O., Gordon, V.S., Mccord, P.H. 2022. Registration of 'CP 13-4100' sugarcane. Journal of Plant Registrations. 16:34-43. https://doi.org/10.1002/plr2.20173.
Sandhu, H.S., Zhao, D., Davidson, W.R., Gordon, V.S., Islam, M.S., Mccord, P.H., Sood, S.G., Baltazar, M., Coto Arbelo, O., Momotaz, A. 2022. Registration of 'CP 12-1417' sugarcane. Journal of Plant Registrations. 16:64-72. https://doi.org10.1002/plr2.20192.
Sood, S.G., Davidson, W.R., Baltazar, M. 2021. Survey of Sugarcane yellow leaf virus in Canal Point breeding and cultivar development program. Agronomy. 11(10):1948. https://doi.org/10.3390/agronomy11101948.
Islam, M.S., Mccord, P.H., Olatoye, M.O., Qin, L., Sood, S.G., Lipka, A.E., Todd, J.R. 2021. Experimental evaluation of genomic selection prediction for rust resistance in sugarcane. The Plant Genome. 14(3). Article e20148. https://doi.org/10.1002/tpg2.20148.
