摘要 Wheat rusts continue to cause significant losses worldwide despite major efforts given to their genetic control. This is due to frequent evolution and selection of virulence in pathogen overcoming the deployed race-specific resistance genes. Although the life of effective race-specific resistance genes can be prolonged by using gene combinations, an alternative approach being implemented at CIMMYT is to deploy varieties that posses adult plant resistance (APR) based on combinations of minor, slow rusting genes. When present alone, the APR genes do not confer adequate resistance especially under high disease pressure; however, combinations of 4 or 5 minor genes usually result in “near-immunity” or a high level of resistance. Although only a few APR genes are catalogued, various APR QTLs are now known and could lead to further characterization of additional genes. Four characterized genes have pleiotropic effects in conferring partial APR to all 3 rusts and powdery mildew, thus simplifying the task of breeding wheat varieties that are resistant to multiple diseases. Significant progress was made recently in developing high-yielding wheat germplasm that possesses high levels of APR to all three rusts by implementing a Mexico- Kenya shuttle breeding scheme. Parents with APR to Ug99 were hybridized with high-yielding parents that had adequate to high levels of APR to leaf rust and yellow rust. Segregating populations and advanced lines from these crosses were selected under high rust pressures in Mexico (leaf rust and yellow rust) and Kenya (Ug99 stem rust and yellow rust) to identify high- yielding progenies that possess high to adequate APR to all three rusts. International distribution of these high-yielding wheats is underway through CIMMYT international yield trials and screening nurseries. It is expected that several wheat varieties with APR to three rusts will be released and grown in various countries in the near-future that will allow determining the durability of resistance.
Abstract Wheat rusts continue to cause significant losses worldwide despite major efforts given to their genetic control. This is due to frequent evolution and selection of virulence in pathogen overcoming the deployed race-specific resistance genes. Although the life of effective race-specific resistance genes can be prolonged by using gene combinations, an alternative approach being implemented at CIMMYT is to deploy varieties that posses adult plant resistance (APR) based on combinations of minor, slow rusting genes. When present alone, the APR genes do not confer adequate resistance especially under high disease pressure; however, combinations of 4 or 5 minor genes usually result in “near-immunity” or a high level of resistance. Although only a few APR genes are catalogued, various APR QTLs are now known and could lead to further characterization of additional genes. Four characterized genes have pleiotropic effects in conferring partial APR to all 3 rusts and powdery mildew, thus simplifying the task of breeding wheat varieties that are resistant to multiple diseases. Significant progress was made recently in developing high-yielding wheat germplasm that possesses high levels of APR to all three rusts by implementing a Mexico- Kenya shuttle breeding scheme. Parents with APR to Ug99 were hybridized with high-yielding parents that had adequate to high levels of APR to leaf rust and yellow rust. Segregating populations and advanced lines from these crosses were selected under high rust pressures in Mexico (leaf rust and yellow rust) and Kenya (Ug99 stem rust and yellow rust) to identify high- yielding progenies that possess high to adequate APR to all three rusts. International distribution of these high-yielding wheats is underway through CIMMYT international yield trials and screening nurseries. It is expected that several wheat varieties with APR to three rusts will be released and grown in various countries in the near-future that will allow determining the durability of resistance.
We acknowledge financial resources from the Durable Rust Resistant Wheat Project led by Cornell University, USA, and supported by the Bill & Melinda Gates Foundation; ICAR-India; USDA-ARS and USAID, USA; GRDC Australia; Agrovegetal-Spain; the Northwestern Mexican Farmer Association (Patronato) and CONFUPRO, Mexico; SDC, Switzerland; and CIMMYT and INIFAP.
Ravi Prakash Singh, Sybil Herrera-Foessel, Julio Huerta-Espino, Sukhwinder Singh, Sridhar Bhavani, Caixia Lan , Bhoja Raj Basnet.
2014.
Progress Towards Genetics and Breeding for Minor Genes Based Resistance to Ug99 and Other Rusts in CIMMYT High-Yielding Spring Wheat. Journal of Integrative Agriculture, 13(2): 255-261.
Bhavani S, Singh R P, Argillier O, Huerta-Espino J, SinghS, Njau P, Brun S, Lacam S, Desmouceaux N. 2011.Mapping durable adult plant stem rust resistance to therace Ug99 group in six CIMMYT wheats. In: McIntosh R,ed., Proceedings of Borlaug Global Rust Initiative 2011Technical Workshop. June 13-16, Saint Paul, Minnesota,USA pp. 43-53
Caldwell R M.1968. Breeding for general and/or specific plant disease resistance. In: Finley K W, Shepherd K W,eds., Proceedings of 3rd International Wheat Genetics Symposium. Australian Academy of Sciences, Canberra,Australia. pp. 263-272
Herrera-Foessel S A, Lagudah E S, Huerta-Espino J, HaydenM J, Bariana H S, Singh D, Singh R P. 2011. New slow-rusting leaf rust and stripe rust resistance genes Lr67and Yr46 in wheat are pleiotropic or closely linked.Theoretical and Applied Genetics, 122, 239-249
Herrera-Foessel S A, Singh R P, Huerta-Espino J,Rosewarne G, Calvo Salazar V, Lan C, Lagudah E S.. 2012. Lr68: a new gene conferring slow rustingresistance to leaf rust in wheat. Theoretical and AppliedGenetics, 124, 1475-1486
Hiebert C W, Thomas J B, McCallum B D, Humphreys D G,DePauw R M, Hayden M J, Mago R, SchnippenkoetterW, Spielmeyer W. 2010. An introgression on wheat chromosome 4DL in RL6077 (Thatcher*6/PI 250413) confers adult plant resistance to stripe rust and leaf rust(Lr67). Theoretical and Applied Genetics, 121, 1083-1091
Krattinger S G, Lagudah E S, Spielmeyer W, Singh R P,Huerta-Espino J, McFadden H, Bossolini E, Selter L L, Keller B. 2009. A putative ABC transporter confers durable resistance to multiple fungal pathogens in wheat.Science, 323, 1360-1363
Lillemo M, Asalf B, Singh R P, Huerta-Espino J, Chen X M, He Z H, Bjørnstad Å. 2008. The adult plant rust resistance loci Lr34/Yr18 and Lr46/Yr29 are important determinants of partial resistance to powdery mildew inbread wheat line Saar. Theoretical and Applied Genetics,116, 1155-1166
McFadden E S. 1930. A successful transfer of emmer characters to vulgare wheat. Journal American Society of Agronomy, 22, 1020-1034
Singh R P. 1992. Genetic association of leaf rust resistancegene Lr34 with adult plant resistance to stripe rust inbread wheat. Phytopathology, 82, 835-838
Singh R P, Huerta-Espino J, Bhavani S, Herrera-Foessel S A, Singh D, Singh P K, Velu G, Mason R E, Jin Y, Njau P,et al. 2011. Race non-specific resistance to rust diseasesin CIMMYT spring wheats. Euphytica, 179, 175-186
Singh R P, Trethowan R. 2007. Breeding spring breadwheat for irrigated and rainfed production systems of developing world. In: Kang M, Priyadarshan P M, eds.,Breeding Major Food Staples. Blackwell Publishing,Iowa, USA. pp. 109-140
Spielmeyer W, McIntosh R A, Kolmer J, Lagudah E S. 2005. Powdery mildew resistance and Lr34/Yr18 genes for durable resistance to leaf and stripe rust cosegregate at a locus on the short arm of chromosome 7D of wheat. Theoretical and Applied Genetics, 111, 731-735.
William M, Singh R P, Huerta-Espino J, Ortiz Islas S, Hoisington D. 2003. Molecular marker mapping of leaf rust resistance gene Lr46 and its association with stripe rust resistance gene Yr29 in wheat. Phytopathology, 93, 153-159
Yu L X, Lorenz A, Rutkoski J, Singh R P, Bhavani S, Huerta-Espino J, Sorrells M E. 2011. Association mapping and gene-gene interaction for stem rust resistance in CIMMYT spring wheat germplasm. Theoretical and Applied Genetics, 123, 1257-1268.