Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: June 17, 2005
Publication Date: August 9, 2005
Citation: Eizenga, G.C., Agrama, H.A., Lee, F.N., Jia, Y. 2005. Continued evaluation of blast resistance genes in rice wild relatives (Oryza spp.) and unique rice (O. sativa) accessions utilizing DNA markers. 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. 30-37. Available: http://www.uark.edu/depts/agripub/Publications/researchseries/ Technical Abstract: Blast, Pyricularia grisea Cav., is a major fungal disease of cultivated rice (Oryza sativa L.) that limits Arkansas rough rice yields and market potential. Resistance to Arkansas blast races was found in rice wild relatives (Oryza spp.). Also, 32 newly introduced cultivated O. sativa accessions were identified as potential sources of unique blast resistance (Pi-) genes that could be incorporated into US rice varieties. SSR markers can determine the genetic distance between the individual accessions, and associations of these SSR markers with blast resistance traits will aid in identifying new and novel Pi-genes. Objectives of this study were to 1) better define the resistance of O. sativa accessions to blast races found in Arkansas and potential new races that might arise in the future, 2) ascertain the relatedness between the Oryza spp. accessions using SSR markers, and 3) identify associations between blast resistance traits and SSR markers in the Oryza spp. and O. sativa accessions. Preliminary data indicate resistance to the new blast isolate IE-1k-Banks in 21 of the 35 O. sativa accessions screened. Associations between blast traits and SSR markers identified eleven markers not associated with known Pi-genes in the O. sativa accessions. Subsequently, analysis of associations between blast and SSR markers in the Oryza spp. accessions identified seven additional chromosomal regions that are potential locations of new Pi-genes. Genetic distance between the various accessions will assist in identifying accessions from a more diverse origin.