Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: 7/6/2005
Publication Date: 8/10/2005
Citation: Gealy, D.R., Estorninos, L.E., Wilson, C.E. 2005. Identifying red rice crosses in Arkansas rice fields. In: Norman, R.J., Meullenet, J.-F., Moldenhauer, K.A.K., editors. B.R. Wells Rice Research Studies 2004, Arkansas Agricultural Experiment Station Research Series 529. p. 201-209. Available: http://www.uark.edu/depts/agripub/Publications/researchseries/ Interpretive Summary:
Technical Abstract: Interest in outcrossing between herbicide resistant rice and red rice has increased since the introduction of imidazolinone (IMI) resistant rice cultivars. We used phenotypic traits and 17 simple sequence repeat (SSR) markers to confirm outcrossing between rice and red rice on three Arkansas farms. A short red rice type from Prairie Co. in 2003 had uniform erect plants with awned seeds, rough leaves, and heights similar to semidwarf rice. SSR detected few heterozygous alleles, suggesting that the plants had selfed several times since crossing. A tall red rice type from Prairie Co. was segregating for leaf texture, and stem and awn color. These plants were erect, much taller than rice cultivars, and produced awned seeds. SSR detected many heterozygous alleles, suggesting that the plants had selfed relatively few times. Second generation plants grown from long grain (LG) red rice seeds found in 2001 in a Cypress field in Arkansas Co. produced LG or medium grain (MG) awnless seeds that were red or white in color, and purple lower stems, and they were genetically similar to cultivated rice. Bushy, rough leaved, IMI resistant plants with delayed heading were obtained in 2004 from Jackson Co. SSR confirmed that these were first generation crosses of IMI rice and awnless red rice because alleles consistent with both IMI rice and awnless red rice standards were detected for all markers. Similarly, non bushy, rough leaved, early heading, IMI resistant plants that produced pink awned, MG seeds were apparently first generation crosses of IMI rice and awned red rice. These studies show that visual observations and SSR analysis can be used in concert to identify specific red rice crosses found in farm fields.