Progress 05/30/20 to 09/30/20
Outputs
Target Audience:This project reached a variety of target audience through our ongoing outreach and academic activities. Target audience included rice producers, rice millers, crop consultants, county extension agents, industry representatives, extensional specialists, scientific communities and the general public. Most of the audience were located in Texas and other southern rice-producing states. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided mentoring and support to train two PhD graduate students, one undergraduate student intern, one postdoctoral researcher, one technical support staff, and one visiting researcher. This project also has provided two virtue field day talks on the updates of rice diseases and management, which will help educate county extension agents, rice farmers, crop consultants about rice disease management. How have the results been disseminated to communities of interest?Results of this project have been disseminated to rice producers, rice millers, crop consultants, county extension agents, chemical industry representatives, extensional specialists and the general public through a variety of outreach activities. These activities include the 2020 Virtual Rice Annual Field Day, two winter extension meetings (Western Texas Rice Belt Conference and Southeast Texas Rice Symposium), one rice crop consultation meeting, nine oral and poster presentations at local, state, and national extension and outreach meetings, and more than ten farm visits. Results of this project also were delivered to national and international scientific communities through the meetings of the 2020 American Phytopathology Society's Virtual Annual Meeting, the 38th Rice Technical Working Group Conference, and the 2020 US Rice Breeders' Annual Meeting, and through article publications in professional and scientific journals. What do you plan to do during the next reporting period to accomplish the goals?We will continue conducting proposed research activites under objectives 1, 2 and 3.
Impacts
What was accomplished under these goals?
1) Improve seedling disease management strategies by better understanding the pathogen populations or causal agents involved, screening germplasm for resistance, and developing effective chemical and biological seed treatment methods. Surveys of fungal pathogens associated with rice seedling diseases in the southern United States (Texas, Louisiana, Arkansas, Mississippi, and Missouri) were conducted to understand the major causes of seeding diseases in dry seeding production systems. More than 70 rice fields in the five rice-growing states were surveyed and more than 380 fungal isolates were collected for pathogenicity tests. Rhizoctonia solani AG11 was the predominant pathogen causing seedling disease, followed by Fusarium spp., and Sclerotium rolfsii. The surveys discovered a new fungal pathogen called Marasminus graminum (sterile white basidiomycete fungus), causing seedling blight of rice, and a new rice seedling disease caused by R. solani AG4. R. solani AG4 was more aggressive in virulence than R. solani AG11, causing more stand loss. A field trial was conducted at Beaumont and Eagle Lake, Texas in 2020 to evaluate the resistance of 40 rice genotypes, including hybrids, to R. solani AG11, a major pathogen causing seedling disease. The pathogen was inoculated into soil prior to seeding and stand loss was assessed at 30 days after seeding. Results from this study indicate that no rice cultivars and breeding lines had a high level of resistance against this pathogen. Majority of these genotypes were very susceptible to this disease. 2) Improve kernel smut management practices by developing a reliable greenhouse inoculation method, screening for resistance germplasm, and identifying effective fungicides and optimum fungicide application timings for main and ratoon crops. Repeated greenhouse tests were conducted to determine the effects of inoculation methods (spray vs. injection) and timing of inoculation on the incidence of rice kernel smut. Although the results were inconsistent, it seemed that the injection inoculation method produced a higher level of infection than the spray method and that inoculation at the boot stage resulted in a high level of disease. A field inoculation trial was conducted for two times in 2020 to verify the effects of timing of the spray inoculation method on rice kernel smut. Inoculation at the boot stage induced the highest level of rice kernel smut. A field trial was conducted at Beaumont, TX to evaluate the efficacy of timing of fungicide applications for control of rice kernel smut in main and ratoon crops. Amistar Top applied at mid-boot was more effective in reducing kernel smut than applied at mid-boot + 14 days. The efficacy of Amistar Top was similar to those of Quilt Xcel and Tilt. The mid-boot stage was the best time to apply fungicide for control of rice kernel smut. 3) Optimize sheath blight and NBLS management practices by screening for resistant germplasm and effective fungicides for main and ratoon crops. A disease nursery was established at Beaumont and Eagle Lake in Texas in 2020 to evaluate the response of rice cultivars or lines to sheath blight and NBLS under Texas environments. The Beaumont site evaluated a total of 65 entries, consisting of 15 inbred and hybrid cultivars from Arkansas, Louisiana, Mississippi, and Texas, 11 elite inbred lines from the Texas Rice Inbred Breeding Program, and 39 hybrid breeding lines from the Texas Rice Hybrid Breeding Program. The Eagle Lake site evaluated a total of 277 entries, consisting of 237 from the Uniform Regional Rice Nursery (URRN) and 40 hybrid breeding lines from the Texas Hybrid Breeding Program. No cultivars or breeding lines had an immune reaction or extremely high levels of resistance to sheath blight. Most of cultivars and lines were rated susceptible or very susceptible to sheath blight. Several inbred lines and most hybrid lines were observed to have partial resistance to sheath blight with a rating of less than 6.0 on a scale of 0 to 9. Most cultivars and elite breeding lines, especially hybrids, had immune reaction or higher levels of resistance to NBLS. These results will assist rice inbred and hybrid breeders in developing new cultivars with improved disease resistance. Two field trials were conducted at two locations in Texas to evaluate the efficacy of 15 fungicide and application timing treatments for control of sheath blight and NBLS in main and ratoon crops. Two new fungicides, Amistar Top and Indeflin, were among the best fungicides in reducing sheath blight. Both new fungicides were more effective than Tilt, and were as effective as Elegia, Equation, Quadris, Quilt Xcel and Sercadis. Amistar Top and Indeflin were also among the best fungicides in reducing NBLS. They provided equal or better control efficacy of NBLS compared to Elegia, Equation, Quadris, Quilt Xcel, Sercadis, and Tilt. Amistar Top was as effective as Tilt for control of NBLS and yield improvement in the ratoon crop.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Zhou, X.G., Liu, G., Zhou, L., and Tabien, R.E. 2020. Resistance of rice cultivars and elite breeding lines to sheath blight and narrow brown leaf spot at Eagle Lake, Texas, 2019. Plant Disease Management Reports 14: CF013.
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Zhou, X.G., Uppala, S.S., Liu, B., Guo, Z., Liu, G., Lei, X., and Gaire, S.P. 2020. Efficacy of fungicides for control of rice kernel smut. Texas Rice Special Section 2020:42-43.
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Gaire, S. P., Zhou, X.G., and Liu, G. 2020. Resistance of rice genotypes against seedling blight and sheath blight. Texas Rice Special Section 2020:41-41.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Lin, F., Gao, S., Tan, C., Zhou, X.G., and Zhang, D. 2020. Identification of rice sheath blight through spectral responses using hyperspectral images. Sensors 20:6243. DOI:10.3390/s20216243.
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Wang, L., Nysetvold, E., and Zhou, X.G. 2020. Propiconazole sensitivity of Tilletia barclayana isolates from the southern United States. Texas Rice Special Section 2020:41-42.
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Way, M.O., Tabien, R., and Zhou, X.G. 2020. Variety selection, early planting critical to high-yielding crops. Rice Farming 54(1):18.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2020
Citation:
Zhou, X.G., Kuma, K.V.K., Zhou, L.W., Reddy, M.S., and Kloepper, J.W. 2020. Combined use of PGPR and reduced rates of azoxystrobin to improve management of sheath blight of rice. Plant Disease 105:
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Zhou, X.G., and Liu, G. 2020. Fungicide seed treatments for early seedling disease control and stand improvement in Texas, 2019. Plant Disease Management Reports 14: CF010.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Zhou, X.G., Liu, G., and Zhou, L. 2020. Effects of application timing of Amistar Top on narrow brown leaf spot, leaf smut and brown spot diseases in main and ratoon rice, 2019. Plant Disease Management Reports 14: CF008.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Zhou, X.G., Liu, G., and Zhou, L. 2020. Efficacy of new fungicides for control of sheath blight and narrow brown leaf spot in rice, 2019. Plant Disease Management Reports 14: CF009.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Zhou, X.G., Liu, G., Zhou, L., and Tabien, R.E. 2020. Resistance of rice cultivars and elite breeding lines to multiple rice diseases at Beaumont, Texas, 2019. Plant Disease Management Reports 14: CF012.
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