Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: June 27, 2006
Publication Date: August 8, 2006
Citation: Eizenga, G.C., Agrama, H.A., Lee, F.N., Yan, W., Jia, Y. 2006. Twelve rice germplasm accessions identified with novel blast resistance for US rice variety improvement. In? Norman, R.J. Meullenet, J.-F. and Moldenhauer, K.A.K., editors. B.R. Wells Rice Research Studies 2005. Arkansas Agricultural Experiment Station Research Series 540. p. 55-61. Available: http:www/uark.edu/depts/agripub/Publications/research series/. Interpretive Summary: Interpretive summary not required for experiment station series.
Technical Abstract: Rice (Oryza sativa L.) germplasm accessions with new major resistance (R-) are constantly sought by rice breeders for use in developing resistant cultivars to control blast (Pyricularia oryza Cav.), a major fungal disease of cultivated rice. Initially, 91 blast resistant rice accessions were selected from more than 1,000 accessions being introduced into the US. Further evaluation identified 27 of the 91 accessions as resistant to all US blast races and not having a major blast resistance gene (Pi-b, Pi-ta) thus, these accessions are potential sources of new blast resistance (Pi-) genes that could be incorporated into US rice cultivars. DNA markers were utilized to identify known Pi-genes and genotype the individual accessions. Objectives were to 1) decipher the probable genetic background of the 91 accessions with DNA markers, and 2) further characterize the 27 selected accessions for genetic diversity, presence of Pi-k and Pi-z, and reaction to the possible new blast race IE 1k-Banks and laboratory race IB-33. Analysis of the DNA marker data divided the 91 accessions into seven clusters with six different genetic backgrounds. The selected 27 accessions divided into five clusters with three different genetic backgrounds. Twelve of the 27 accessions were resistant to all known US blast races including IE-1k-Banks and IB-33, and divided into four clusters with three genetic backgrounds. The blast resistant accessions have excellent agronomic characteristics and are currently being used by Arkansas rice breeders.