Authors
C. X. Lan and R. P. Singh, International Maize and Wheat Improvement Center (CIMMYT), 06600, México D.F., Mexico; J. Huerta-Espino, Campo Experimental Valle de México INIFAP, 56230, Chapingo, Edo. de México, Mexico; and V. Calvo-Salazar and S. A. Herrera-Foessel, International Maize and Wheat Improvement Center (CIMMYT), 06600, México D.F., Mexico
Abstract
Leaf rust and stripe rust are important diseases of wheat and can be controlled by growing resistant varieties. We investigated the genetic basis of resistance to both rusts in 198 F5 recombinant inbred lines derived from a cross between ‘Avocet’ and ‘Francolin#1’. The population was phenotyped in greenhouse and field, and genotyped with known gene-associated molecular markers. Seedling resistance of Francolin#1 to leaf and stripe rusts was attributed to the loosely linked genes Lr16 and YrF, respectively, with a recombination frequency of 0.36. Field segregation indicated that adult plant resistance (APR) to leaf and stripe rusts was conferred by three and five additive genes, respectively. Among them, Lr46/Yr29 was associated with resistance to both rusts in Francolin#1, Lr16 reduced field leaf rust severity by 8 to 9%, and YrF contributed to 10 to 25% reductions in stripe rust severity. The Lr16 region was also associated with a 5 to 16% reduction in stripe rust severity, which is likely due to its linkage with YrF or another unidentified stripe rust APR gene. Significant additive effects on stripe rust were detected between YrF and Yr29. We conclude that APR in Francolin#1 to leaf and stripe rusts involves a combination of seedling and APR genes.
