2012 Annual Report
1a.Objectives (from AD-416):
The objectives of the project are:.
1)test U.S. wheat cultivars for resistance to the wheat blast pathogen, Magnaporthe grisea;.
2)characterize wheat blast resistance; and.
3)develop tools for the rapid detection of M. grisea. This project will enhance research in Project 1920-220000-035-00D, under Sub-objectives 1.A “ Develop accurate and rapid means for identification and detection”, 2.B “Elucidate the range of potential hosts for foreign plant pathogens”, 2.C “Evaluate environmental parameters on the initiation, establishment and progression of disease”, and 3” Screen germplasm for resistant sources to emerging and foreign fungal plant pathogens”.
1b.Approach (from AD-416):
A nursery of U.S. commercial wheat cultivars will be established at the Foreign Disease-Weed Science Research Unit. Plants in the vegetative stage will be inoculated with conidia of M. grisea and subsequent disease assessed 7 days after inoculation. A disease rating scale has already been established. Each cultivar will be tested with a minimum of 5 geographically distinct isolates of M. grisea from Mato Grosso do Sul and Parana, Brazil, where the disease is a major problem. These trials will be repeated three times. Cultivars identified as resistant will be field tested in Brazil through a cooperator in Brazil.
Twenty-one winter wheat cultivars that showed less than 10 percent infection to a single isolate of Magnaporthe oryzae (wheat blast) collected in Brazil, in 1988, were re-tested twice with a new isolate of M. oryzae collected in Bolivia in 2012. No significant differences were observed among the wheat lines in resistance to the two M. oryzae isolates. Twenty-four wheat cultivars, 12 from ARS at Fort Detrick and 12 from Kansas State University were sent to cooperators in Bolivia, the Association of Wheat Growers and Oilseeds (Anapo), for vernalization and field tested in a randomized replicated study to assess resistance. Seventy-eight of 400 U.S. spring wheat cultivars have been tested for resistance to a single isolate M. oryzae at the FDWSRU. Studies to determine the effect of dew period, temperature and conidial concentration on wheat infection, the rate of seed transmission and the efficacy of existing fungicidal seed treatments are ongoing as containment greenhouse space permits. An invited presentation on wheat blast was given at the USDA-ARS-NCERA-184 Committee’s Annual Meeting in Memphis, Tennessee, on March 27, 2012. A project meeting was held on March 29, 2012 between ARS, Kansas State University and Brazilian Agricultural Research Corporation (EMBRAPA) cooperators at the Biosecurity Research Institute in Manhattan, Kansas.