Submitted to: International Weed Science Society
Publication Type: Proceedings
Publication Acceptance Date: 4/25/2008
Publication Date: 6/22/2008
Citation: Gealy, D.R., Bockelman, H.E. 2008. Southern U.S. weedy red rice(Oryza sativa) accessions for entry into the National Small Grains Collection. International Weed Science Society. p.
Technical Abstract: Red rice (Oryza sativa) is a troublesome weed in rice (Oryza sativa) production systems in the southern U.S. and throughout the world, especially where direct seeding methods are employed. Diverse biotypes of red rice infest rice in the southern U.S. This creates a challenge for management and control of red rice, but also creates an opportunity for detailed biological and genetic studies of this introduced weed in relation to rice and other relatives. There is a need for researchers working in areas of weed biology and control, genetics, gene flow, molecular biology, and evolutionary biology to have access to red rice germplasm. The National Small Grains Collection (NSGC) is designed to provide such service, but emphasizes maintenance and distribution of crop rice germplasm and not weedy rice. A single U.S. weedy red rice accession, CIor 9749, that was originally acquired by the NSGC from Louisiana in 1969, is no longer available for distribution from that germplasm source. Thus, adding a collection of new red rice germplasm accessions to the NSGC would satisfy a real need in the rice-weedy red rice community. In order to accomplish this, 28 accessions of red rice that had been acquired at DBNRRC from 1994 to 2000 from geographically diverse locations in Arkansas, Mississippi, Louisiana, Missouri, and Texas, have been processed for entry into the NSGC. All accessions have been evaluated in field plots at Stuttgart, AR for several years in order to characterize key agronomic traits and to remove off-types. Approximately half of the accessions were developed from single seed descent, and thus, should be well suited for molecular biology studies. Phenotypes are typically blackhull or strawhull, and awned or awnless. Days from emergence to heading range from 71 to 90 d, plant heights range from 149 to 182 cm, and kernel length/width ratios range from 2.5 to 3.3. Tillering and grain yield potential of the accessions also differ significantly. Specialty traits present in some accessions include cold tolerance or susceptibility, blast disease tolerance or susceptibility, herbicide tolerance, and seed dormancy. Seed samples will be available for scientific purposes in 5-g quantities from the NSGC through the Germplasm Resources Information Network (GRIN; http://www.ars-grin.gov/npgs/). Additional detailed background information on these accessions will also available on this website.