46-2 CIMMYT Breeding Progress for Tolerance to Maize Lethal Necrosis in Eastern Africa.

See more from this Division: C01 Crop Breeding & Genetics
See more from this Session: Crop Breeding and Genetics: I

Monday, November 16, 2015: 8:20 AM
Minneapolis Convention Center, 101 FG

Michael Olsen1, Biswanath Das1, Yoseph Beyene1, Lewis Machida1, Dan Makumbi1, Mosisa Regasa1, Manje Gowda1, MacDonald Jumbo1, Kassa Semagn1, George Mahuku2, Rumbidzai Matemba Mutasa3, Monica Mezzalama4, Denise E. Costich5, Terence Molnar5, Daniel P Jeffers6, James Karanja7, Mark Jones8, Margaret Redinbaugh8 and Prasanna B.M.1, (1)Global Maize Program, CIMMYT, Nairobi, Kenya
(2)Plant Production and Health, International Institute for Tropical Agriculture, Dar es salaam, Tanzania
(3)Global Maize Program, CIMMYT, Harare, Zimbabwe
(4)CIMMYT, Texcoco, Mexico
(5)Global Resources Program, CIMMYT, Texcoco, Mexico
(6)Institute of Food Crops(CIMMYT-China), Yunnan Academy of Agricultural Science, Kunming, China
(7)Kenya Agriculture and Livestock Research Organization (KALRO), Nairobi, Kenya
(8)Corn Soybean and Wheat Quality Research, USDA ARS, Wooster, OH
Abstract:
Maize lethal necrosis (MLN) has emerged as a serious threat to maize production in eastern Africa, resulting in significant yield reduction up to total crop failure.  MLN in the region is most commonly caused by the co-infection of maize chlorotic mosaic virus (MCMV) and sugarcane mosaic virus (SCMV).   The current east African epidemic was precipitated by the recent introduction and rapid spread of MCMV.  Environmental stresses such as drought and heat also play a major role in disease severity.  Since 2011, MLN has become established in six east African countries, negatively impacting the livelihood of maize smallholder farmers.  Additionally, the vast majority of African maize lines and commercially available varieties are highly susceptible to MLN.  In conjunction with the Kenya Agriculture and Livestock Research Organization (KALRO) and other regional partners, CIMMYT has identified hybrids with moderate tolerance to MLN which demonstrate significant yield advantage over widely grown hybrids under natural MLN infestation.  Promising sources of MLN tolerance have been identified from global resources including CIMMYT elite breeding panels, a USDA virus resistant line collection, and maize landrace accessions from the CIMMYT gene bank.  Among the most tolerant lines identified to date are CML494, a tropical lowland line developed in Mexico, and KS523-6, a tropical line from Katsetsart University.  Landrace accessions from Latin America and the Caribbean with tolerance to MCMV have also been identified.  Major QTL for MLN tolerance have been identified and are being introgressed into elite African lines.  Strategies for accelerating genetic gain for yield under MLN pressure are also being implemented.  A summary of MLN screening, QTL discovery and breeding for MLN tolerance will be presented.

See more from this Division: C01 Crop Breeding & Genetics
See more from this Session: Crop Breeding and Genetics: I