Location: Dale Bumpers National Rice Research Center
Project Number: 6028-21000-012-026-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 11, 2026
End Date: Sep 30, 2027
Objective:
Identify control measures and validate quantitative trait loci (QTLs) associated with resistance to rice delphacid and RHBV infection in diverse germplasm, and initiate development of molecular tools for marker-assisted selection and biotechnology-based resistance.
Approach:
Field Sampling and Surveys:Beginning May 2026, Louisiana, Texas, and Arkansas fields will be surveyed for symptomatic leaves, asymptomatic bulk samples, and planthopper vectors. Data on RHBV prevalence, symptom severity, and vector abundance will support spatial–temporal analyses of vector movement, disease intensity, and potential yield loss.Arkansas Delphacid Management:Research plots in southeast Arkansas will evaluate insecticide programs and rice cultivars for effects on delphacid populations. Symptomatic plants will be collected for diagnostics, and regional delphacids will be tested for RHBV to assess viruliferous pressure.Louisiana Surveys:Sweep-net surveys will document vector presence and scout for Hoja Blanca symptoms. Insects and plant samples will be tested for RHBV to estimate viruliferous vector levels statewide.Texas Activities:SY will survey outbreak regions, collect infected plants and vectors, and sequence representative isolates to characterize Texas RHBV diversity. Resistant cultivars and breeding lines will be evaluated under natural infection in main and ratoon crops.Diagnostics and Molecular Work:ELISA and RT-PCR will be used for virus detection in plant and insect tissues. PI lab will develop and optimize an RT-qPCR assay in collaboration with SY. Selected isolates will undergo next-generation sequencing to characterize diversity and emerging variants.Louisiana Diagnostics:SY will lead RNA extraction, RT-PCR, ELISA testing, and co-develop the RT-qPCR assay for quantitative detection.Epidemiology and Distribution:SY will conduct statewide sampling in Louisiana to document disease distribution and analyze relationships among vector density, epidemic progress, and disease incidence.Resistance Screening:Candidate varieties with RHBV resistance QTLs or other resistance traits will be screened across PI and co-PI locations to support breeding for improved resistance.Project Coordination:PI will coordinate meetings, sample transfer, and analyses. Quarterly meetings will review progress. Results will be shared with stakeholders through reports, presentations, publications, and extension programs in collaboration with regional rice research units.