Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 24, 2002
Publication Date: N/A
Technical Abstract: The rice blast resistance genes Pi-ta and Pi-ta2 are closely linked or allelic to each other on rice chromosome 12. Pi-ta2 historically confers resistance to all Magnaporthe grisea races except IB33 and IE1K in the U.S. The inheritance of the resistance gene(s) against race IB49 was investigated in two F2 populations. Pi-ta allele specific primers were used to identify Pi-ta in a F2 population of 349 individuals of Kaybonnet and Maybelle that are co-dominant for micro-satellite markers [SSR (OSM89 and MRG102)]. A ratio of 1 homozygous resistance (RR):2 heterozygous resistance (RS):1 homozygous susceptible (SS) was discovered in this F2 population. The Pi-ta gene was only identified in the resistant individuals (RR and RS). No recombinants between Pi-ta and IB-49 resistance (presumably Pi-ta2) were recovered. These data suggest that resistance genes (Pi-ta and Pi-ta2) against IB49 are indistinguishable. An nF2 population of 280 individuals of Kaybonnet and M204 were then used for further analysis. A ratio of 1:2:1 (RR:RS:SS) was also discovered and two potential recombinants were discovered using Pi-ta separate from Pi-ta, it is less than 0.2 cM away with pi-ta2 upstream of Pi-ta and the centromere downstream. Further analysis of any recombination event between OSM89 and MRG6102 (and Pi-ta2) that may help to distinguish Pi-ta from Pi-ta2 will be presented.