APS Abstract of Presentation

Roelfs F2007, a new bread wheat variety with improved resistance to stripe rust and leaf rust for southern Sonora, Mexico
P. FIGUEROA-LOPEZ (3), G. Fuentes-Davila (3), R. P. Singh (1), J. Huerta-Espino (2)
(1) CIMMYT, Km 45 carret. Mexico-Veracruz, El Batan, Texcoco, Edo. de Mexico, Mexico; (2) Campo Experimental Valle de Mexico, INIFAP. Km 38.5 carret. Mexico-Texcoco, Chapingo, Edo. de Mexico, Mexico; (3) Campo Experimental Valle del Yaqui, CIRNO-INIFAP. Apdo. Postal 515. C. Norman E. Borlaug Km 12, Cd. Obregon, Sonora, Mexico
Phytopathology 98:S54

Southern Sonora is the main wheat producing area in Mexico, where 255,666 ha were planted under irrigation during the crop season 2007–2008. Although durum wheat (Triticum turgidum) predominates, bread wheat occupies about 20% of the area. Historically, leaf rust (Puccinia triticina) and Karnal bunt (Tilletia indica) were the most important diseases. However, since 2000, stripe rust have been increasingly important, as new populations of Puccinia striiformis established in the region. Tacupeto F2001 is currently the most popular bread wheat cultivar with 22,900 ha planted, but has shown moderate susceptibility to stripe rust (up to 80% severity), moderate resistance to leaf rust (up to 40% severity) and has needed fungicide control. Roelfs F2007, selected from (Tacupeto F2001*2/Kukuna) has similar agronomic characteristics, Karnal bunt resistance and grain yield potential, as compared to Tacupeto F2001, as well as improved resistance to stripe rust, leaf rust and quality characteristics. Roelfs F2007 is known to have, from its Kukuna parent, the Lr34/Yr18 complex, which is allowing this cultivar to express an infection type of moderate resistance to stripe rust (up to 40% severity) and to leaf rust (up to 20% severity). Roelfs F2007 is intended to displace Tacupeto F2001 in the regional cultivar mosaic in the next two to three years.