USE OF DIVERSE GERMPLASM FOR GENETIC IMPROVEMENT OF RICE
Location: Dale Bumpers National Rice Research Center
Title: Blast vulnerability detected in novel blast-resistant germplasm.
Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: July 6, 2007
Publication Date: August 8, 2007
Citation: Lee, F.N., Eizenga, G.C. 2007. Blast vulnerability detected in novel blast-resistant germplasm. In: R.J. Norman, J.-F. Meullenet and K.A.K. Moldenhauer (eds) B.R. Wells Rice Research Series 2006. Arkansas Agricultural Experiment Station Research Series 550:139-145. Available at http://arkansasagnews.uark.edu/408.htm
Previous research in artificially inoculated greenhouse tests and field nurseries identified new rice germplasm accession as being resistant to the common blast (Pyricularia grisea) races found in Arkansas (IB-1, IB-49, IC-17, IE-1, IE-1k, IG-1, and IH-1) and eliminated those accessions with major blast resistance genes (Pi-b, Pi-ta) currently utilized in U.S. varieties, thus identifying accessions with novel blast-resistant genes that could be incorporated into resistant varieties for Arkansas producers. Subsequent testing revealed an unanticipated blast vulnerability to archived P. grisea races, IB-45, IB-54, and ID-13, which predominated during the 1950s and 1960s, in several of the resistant accessions. When inoculated with race ID-13, very-susceptible-type 7 to 8 leaf lesions developed in all tests of very closely related accessions 4607, 4611, 4612, 4632, 4642, 4593, 4594, 4633, and 4641(1); and R 312. Also, Guang 6ai-4, Wab450-24-3-2-P18-hb, and Wab450-I-B-P-62hb developed susceptible-type 5 to 6 lesions in one or more tests inoculated with ID-13. Susceptible-type 4 to 7 leaf lesions developed on all the aforementioned accessions in two of the four tests inoculated with race IB-54. A limited vulnerability to race IB-54 was also noted for all accessions and to race IB-17 for Wab450-24-3-2-P18-hb, Wab450-I-B-P-62-hb, and R 312. Most importantly, with the exception of a single IB-54 test, two accessions, ‘Kechengnuo No. 4’ and ‘Shufeng 117’, tested resistant to all the archived blast races to date.