Foward & Reverse Genetics for Rice Improvement, 2022


Thomas H. Tai, Research Geneticist, USDA/ARS Crops Pathology and Genetics Research Unit, Dept. of Plant Sciences, UC Davis

During 2022, characterization of herbicide target gene and metalloid uptake/accumulation gene mutants could not be addressed due to problems with germinating seeds of the mutant lines. The primary focus for the year shifted to identifying a new field site for mutant population development and evaluation.

The feasibility of the UC Davis Plant Sciences Row Crop Facility (RCF) to support generation advance, seed increase, and trait evaluation was tested and the location was found to be suitable. Large, flooded paddies are not possible at RCF as they have been at other locations. The season was spent becoming familiar with the production practices at the RCF and identifying issues and planting/ production solutions for next season. Seeds were produced from about 250 Kitaake M8 mutant families and a few varieties and lines for other projects.

Drone-based phenotyping was initiated, and multispectral imaging data was collected from the RCF site. Analysis of this data looking at various traits such as plant height and coloration is underway in preparation for more rigorous efforts in 2023.

Finally, remnant mutant populations derived from the variety Sabine were screened for resistance to the ACCase-inhibiting herbicide clethodim. Some reputedly resistant mutants were identified, although there were issues with the reliability of the screening. It is probable these plants will prove to be escapes rather than resistant. Nonetheless, the strategy and logistics for herbicide screening at the new site have been worked out. Additional screening to make use of thousands of remnant mutant lines before they lose viability, will be conducted if funding is available next year.