ARS | Publication request: Identification of Blast Resistance Genes in Rice Wild Relatives (Oryza SPP.) and Newly Introduced Rice (O. Sativa) Lines

Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Acceptance Date: February 17, 2004
Publication Date: August 10, 2004
Citation: Eizenga, G.C., Lee, F.N., Jia, Y. 2004. Identification Of Blast Resistance Genes In Rice Wild Relatives (Oryza SPP.) And Newly Introduced Rice (O. Sativa) Lines. Arkansas Agricultural Experiment Station Research Series 417. P. 29-36.

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 common US blast races was observed in some rice wild relatives (Oryza spp.) and 94 newly introduced cultivated rice accessions, indicating these are possible sources of unique blast resistance genes (Pi-genes) that could be incorporated into US rice varieties. Pi-ta and Pi-b are major blast resistance genes which have been characterized molecularly. Objectives of this study were to identify Pi-ta and Pi-b in the aforementioned accessions and determine the relatedness of the O. sativa accessions using microsatellite markers. Results indicate Pi-ta is present in O. barthii, O. nivara and O. rufipogon accessions and Pi-b in O. barthii, O. glumaepatula and O. rufipogon accessions. Alleles of Pi-ta, pi-ta and/or Pi-b were detected in 60 O. sativa accessions using dominant/recessive gene markers indicating their resistance was not new. Of the remaining 34 blast resistant accessions, 26 originated in China and potentially contain novel blast resistance genes for utilization by US rice breeding programs. Genetic distance, as determined using 111 microsatellite markers, indicated some accessions had a diverse origin and many of these had good agronomic characteristics. These accessions should be useful for incorporating novel resistance to blast into advanced US rice breeding lines.