Submitted to: Proceedings of the Hydro GIS 96 Conference
Publication Type: Proceedings
Publication Acceptance Date: 9/15/1995
Publication Date: N/A
Technical Abstract: To determine the number of major resistance gene(s) to rice blast, parents of F1 and F2 seedlings of Lemont x Teqing and Rosemont x Teqing crosses were prick-inoculated with IB49, IB54, IC17, IG1, and IE1 races of Pyricularia grisea. In addition, a replicated set of Lemont x Teqing recombinant inbred lines (RILs) were spray-inoculated in the greenhouse as well as evaluated in a field nursery. Single race and two-race reaction data suggested that Teqing has at least four genes - two genes each effective against three races and two genes conferring resistance to single races. Lemont apparently has one recessive gene and at least one dominant gene. The reaction of RILs in the blast nursery was generally consistent with greenhouse inoculation tests. RILs that were resistant to all five races in the greenhouse study generally had smaller diseased leaf area in the field study. However, some RILs that were susceptible to all races as well as some that were resistant to only a single race had similar disease leaf area in the field as RILs that were resistant to two or more races in the greenhouse, suggesting the presence of rate-reducing or partial resistance genes. Current RFLP genotyping of the RILs to map and tag the resistance genes in Lemont and Teqing will be discussed.