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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #445311

Research Project: Leveraging Rice Mutant Resources for Trait Discovery, Analysis, and Germplasm Enhancement

Location: Crops Pathology and Genetics Research

Project Number: 2032-21000-027-000-D
Project Type: In-House Appropriated

Start Date: Feb 13, 2023
End Date: Feb 12, 2028

Objective 1: Characterize novel traits and mutations in rice affecting grain quality, yield, and climate resiliency. Sub-objective 1.A: Characterize endosperm mutant phenotypes and their underlying mutations to determine their potential for non-table rice uses. Sub-objective 1.B: Determine the role of cuticular waxes and silicon in the response of rice plants to their environment. Objective 2: Expand select genetic resources for elucidating agriculturally important processes, e.g., climate resilience, and improving rice germplasm. Sub-objective 2.A: Generate and make publicly available germplasm from mutants previously identified by forward and reverse genetics. Sub-objective 2.B: Develop and make publicly available rice mutant populations for genetics and breeding.

Objective 1: Genetic crosses of two mutant-derived rice lines will be performed to generate germplasm and provide materials for trait evaluations and gene expression studies. Sequencing-based strategies will be used to identify the causal mutations in both rice lines. Seed amplification and field-based phenotyping using a randomized complete block design will be conducted to facilitate evaluation including grain and agronomic traits. Physicochemical tests and assays specific to characterization of brewing properties will be conducted on the grains of the germplasm developed from genetic crosses. Established statistical methods will be employed to determine the significance of any trait differences observed between rice lines. The same methods and strategies will be used for developing genetic materials and identifying causal mutations in cuticle wax deficient mutants. Field and greenhouse-based assays will be used to evaluate the performance of and collect data from these wax deficient mutants in response to abiotic and biotic stresses. Statistical analyses of trait data will be conducted to determine the significance of any differences observed between mutant lines in response to environmental conditions. Objective 2: Previously identified rice mutants will be genetically crossed to their wild type progenitor varieties to remove or minimize the presence of mutations unrelated to the mutant traits of interest. Seeds from the resulting mutants lines will be increased and deposited into ARS rice gene banks for distribution to the research community. Mutant populations derived from three rice varieties (Kitaake, Sabine, and Nipponbare) will be grown in the field for seed increase and trait evaluations using an augmented randomized complete block design. Seeds and trait data, including digital documentation of visible mutant phenotypes, will be deposited in ARS rice gene banks for distribution to interested researchers. More detailed phenotypic or trait evaluations will be conducted on fixed mutant lines derived from the variety Kitaake. Data will also be obtained from sequencing a small subset of the Kitaake rice mutants and used to assess the number of mutations in this population.