Marker Development for Rice Blast Resistance Gene Pi66(t) and Application in the USDA Rice Mini-Core Collection

Molecular markers are useful for the identification of critical genes controlling agricultural traits of interest in crop germplasm and for the use of these genes in crop improvement using marker-assisted selection (MAS). The improvement of blast disease resistance of rice (Oryza sativa L.) varieties is one of the major goals for rice breeders. The blast resistance (R) gene Pi66(t) was previously mapped to a 129-kb genomic region on chromosome 11, where six candidate R genes were predicted. To help rice breeders in rice blast resistance MAS breeding, we developed three polymerase-chain-reaction (PCR)-based molecular markers, WRKY41, NBS-LRR-970-1, and NBS-LRR-970-2, for the Pi66(t) locus. The validation of two markers, WRKY41 and NBS-LRR-970-1, suggested they cosegregated with the Pi66(t) gene in two recombinant inbred line (RIL) populations. The application of two markers in a USDA–ARS rice mini-core collection indicated that NBSLRR-970-1 was a Pi66(t)-linked specific marker. The developed marker not only can be used to identify resistant lines with the Pi66(t) gene in mapping populations but also can be used in screening rice germplasm with a broad genetic background. Taken together, these newly developed markers and newly identified rice germplasm lines carrying the Pi66(t) gene will provide essential tools and materials for rice breeders in MAS breeding. Y. Liu, Univ. of Arkansas, Rice Research and Extension Center, Stuttgart, AR 72160; Y. Jia and D. Gealy, USDA–ARS Dale Bumpers National Rice Research Center, Stuttgart, AR 72160; D.M. Goad and K.M. Olsen, Washington Univ., Dep. of Biology, St. Louis, MO 63130-4899; and A.L. Caicedo, Univ. of Massachusetts Amherst, Biology Dep., MA 01003. Received 8 July 2015. Accepted 25 Nov. 2015. *Corresponding author ([email protected]). Abbreviations: DGWG, rice cultivar Dee Geo Woo Gen; LRR, leucine-rich repeat; MAS, marker-assisted selection; NBS, nucleotidebinding site; PCR, polymerase chain reaction; QTL, quantitative trait loci; R, resistance; RFLP, restriction fragment-length polymorphism; RIL, recombinant inbred line. Published in Crop Sci. 56:1001–1008 (2016). doi: 10.2135/cropsci2015.07.0422 © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved.