VIEW ARTICLE

Genetics

Inheritance of Resistance to Pyricularia oryzae in Rice Cultivars Grown in the United States. M. A. Marchetti, Research plant pathologist, U.S. Department of Agriculture, Agricultural Research Service, Texas A&M University Agricultural Research and Extension Center, Beaumont 77706; Xinghua Lai(2), and C. N. Bollich(3). (2)Research plant pathologist, Guangxi Academy of Agricultural Sciences, Nanning, People’s Republic of China; (3)Research agronomist, U.S. Department of Agriculture, Agricultural Research Service, Texas A&M University Agricultural Research and Extension Center, Beaumont 77706. Phytopathology 77:799-804. Accepted for publication 12 November 1986. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1987. DOI: 10.1094/Phyto-77-799.

Inheritance studies were conducted with U.S. rice cultivars to identify and characterize genes for resistance to local pathotypes of Pyricularia oryzae. Three new recessive resistance (Pi-) genes were identified: pi-n in Brazos (resistance to race IB-54 of P. oryzae), pi-g in Gulfrose (IG-1), and pi-d in Lebonnet (IB-1). Brazos also had the Pi-k^s gene (IB-54), independent of the pi-n gene. The Pi-z gene (IC-17, IG-1, and IH-1) was identified in Gulfrose and Vista with Vista also having independently inherited Pi-k^s. Lebonnet and most related cultivars have the Pi-k^h gene (IB-45, IB-54, IG-1, and probably IH-1), which is closely linked to the recessive pi-d gene (3.3% crossover value). An unnamed dominant Pi-gene (IH-1), independent of Pi-z, was identified in PI 331581 (dwarf Bluebelle). Another unnamed Pi-gene, independent of Pi-k^h, which confers resistance to race IB-49, which is virulent on all U.S. commercial rice cultivars, was identified in the international blast differential cultivar Usen.