title: Introgression of Blast Resistance Genes (Putative Pi-b and Pi-kh) into Elite Rice Cultivar MR219 through Marker-Assisted Selection.
abstract: Blast is the most common biotic stress leading to the reduction of rice yield in many rice-growing areas of the world, including Malaysia. Improvement of blast resistance of rice varieties cultivated in blast endemic areas is one of the most important objectives of rice breeding programs. In this study, the marker-assisted backcrossing strategy was applied to improve the blast resistance of the most popular Malaysian rice variety MR219 by introgressing blast resistance genes from the Pongsu Seribu 2 variety. Two blast resistance genes, Pi-b and Pi-kh, were pyramided into MR219. Foreground selection coupled with stringent phenotypic selection identified 15 plants homozygous for the Pi-b and Pi-kh genes, and background selection revealed more than 95% genome recovery of MR219 in advanced blast resistant lines. Phenotypic screening against blast disease indicated that advanced homozygous blast resistant lines were strongly resistant against pathotype P7.2 in the blast disease endemic areas. The morphological, yield, grain quality, and yield-contributing characteristics were significantly similar to those of MR219. The newly developed blast resistant improved lines will retain the high adoptability of MR219 by farmers. The present results will also play an important role in sustaining the rice production of Malaysia.
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra MalaysiaSelangor, Malaysia; Department of Plant Breeding and Genetics, Faculty of Crop Production, Sindh Agriculture University TandojamSindh, Pakistan.
authors.forename: Fatah A
authors.initials: FA
authors.lastname: Tanweer
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra MalaysiaSelangor, Malaysia; Laboratory of Food Crops, Institute of Tropical Agriculture, Universiti Putra MalaysiaSelangor, Malaysia.
authors.forename: Mohd Y
authors.initials: MY
authors.lastname: Rafii
authors.affiliation: Department of Plant Protections, Faculty of Agriculture, Universiti Putra Malaysia Selangor, Malaysia.
authors.forename: Kamaruzaman
authors.initials: K
authors.lastname: Sijam
authors.affiliation: Agrotechnology and Bioscience Division, Malaysian Nuclear Agency Selangor, Malaysia.
authors.forename: Harun A
authors.initials: HA
authors.lastname: Rahim
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia Selangor, Malaysia.
authors.forename: Fahim
authors.initials: F
authors.lastname: Ahmed
authors.affiliation: Laboratory of Food Crops, Institute of Tropical Agriculture, Universiti Putra MalaysiaSelangor, Malaysia; Department of Agronomy and Plant Breeding, Islamic Azad University of Yadegar-e-Imam Khomeini (RAH) BranchTehran, Iran.
authors.forename: Sadegh
authors.initials: S
authors.lastname: Ashkani
authors.affiliation: Bangladesh Rice Research Institute Gazipur, Bangladesh.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Latif
keywords: MABC; biotic stress; blast resistance; gene pyramiding; marker-assisted backcrossing; rice