Development of Monogenic and Digenic Rice Lines for Blast Resistance Genes Pi‐ta, Pi‐kh/Pi‐ks

Abstract

The major blast resistance (R) genes Pi‐ta, Pi‐ks, Pi‐kh have been effectively deployed in rice (Oryza sativa L.) in the southern USA for preventing disease caused by the predominant U.S. races of Magnaporthe oryzae Cav. [=Magnaporthe grisea (Herbert) Barr.]. In the present study, the codominant single nucleotide length polymorphism DNA marker for the Pi‐ta gene, and the simple sequence repeat markers, RM144 and RM224, that cosegregate with two alleles of the Pi‐k gene, Pi‐ks and Pi‐kh, were used for R identification in a F10 recombinant inbred line population. This population (Reg. no. MP‐3, NSL 452303) was derived from the cross RU9101001/‘Katy’. This population composed of 235 individual lines was jointly released on 24 Apr. 2009 by the USDA–ARS and the University of Arkansas Division of Agriculture Arkansas Agriculture Experiment Station. R gene containing RIL lines were verified with standard pathogenicity assays by means of a set of differential races of M. oryzae in the USA. One hundred eighty‐two pure lines were identified from the population with the Pi‐ta, Pi‐ks, and Pi‐kh genes. A total of 56 had Pi‐ta and Pi‐ks, 51 lines had Pi‐ks, 27 had Pi‐kh, and 48 lines had Pi‐kh and Pi‐ta. These monogenic and digenic rice lines with the major blast R genes are expected to be useful for studying effects of each R gene singly and in combination for their epistatic interaction with yield and for introducing blast resistance with marker assisted selection.