Genetics for Rice Improvement, 2021

 

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

The overall goal of this project is to employ trait and DNA-based genetic screens to identify and characterize novel rice germplasm that advances the understanding of agronomic performance and grain quality for incorporation into breeding programs for the California rice industry.

Screening Rice Mutants for Herbicide Tolerance

Using mutant populations, this project has identified candidates for herbicide tolerance. Tolerance is being examined for four herbicide chemistries (with multiple chemistry groups within a type): PPO, HPPD, ACCase, and GS. Because of small seed inventories,herbicide tolerance will be eval;uated using cotton swab applications to individual leaves. Evaluations of the mutants will occur during Winter 2021-22.

Metalloid Element Uptake and Accumulation in Rice Mutants

In 2019, total arsenic and silicon content were determined from leaves and brown rice of mutants and wild-type (Nipponbare) plants grown in 2018 at the UC Davis rice field facility and the Rice Experiment Station.

Data was obtained for the metalloid elements antimony (Sb), arsenic (As), boron (B), germanium (Ge), and silicon (Si). An initial look at the mass spectrometry data indicates that the Si content of the leaves was consistent with previous analyses with very little present in the mutant E-1746 and a significant reduction in mutant 3403 (both lsi1 mutants) but no significant differences between wildtype Nipponbare and the other mutant lines. More detailed analysis of the data from other metalloids (As, B, Ge, and Sb) is needed to determine if there are any significant differences between the mutant lines and wildtype and whether there may be a location effect.

The project facilitated a generation advance of the Kitaake rice mutant population with approximately 600 M8 lines planted. The seeds from these lines and a set of 155 M8 lines grown in 2019-20 will be planted in the field in 2022 for trait evaluations and seed increase. Lines carrying mutations in herbicide target genes and in metalloid uptake/accumulation genes are being planted in the greenhouse this winter for evaluation and other studies in 2022.