Marker-assisted development of dry bean cultivars with resistance to bean common bacterial blight, anthracnose and bean common mosaic virus for reduced use of pesticides
Project code: PRR03-640
Soon Park and Parthiba Balasubramanian - Agriculture and Agri-Food Canada
To develop new varieties of dry beans with resistance to common bacterial blight, bean common mosaic virus, and anthracnose
Summary of Results
Common bacterial blight (CBB), anthracnose and bean common mosaic virus (BCMV) are important seed-borne diseases of dry bean in Canada. Common bacterial blight is observed in all five provinces where dry bean is grown. Several races of anthracnose fungus have been reported primarily in Ontario and Manitoba, while bean common mosaic virus is observed in Idaho and Washington states where pedigreed seed of Canadian dry bean cultivars is produced. A breeding project was undertaken at AAFC research centres in Harrow, Ontario, Morden, Manitoba and Lethbridge, Alberta to develop dry bean cultivars with resistance to these diseases. In Canada, dry bean is produced in Ontario, Manitoba, Alberta, Saskatchewan and Quebec. Currently, the options available for management of these diseases (antibiotics and copper compounds for CBB and seed-treatment and foliar fungicides for anthracnose) have economic as well as environmental downsides associated with their use. Genetic resistance is the most environmentally-sound and cost effective approach for the long term management of these serious production issues.
A number of dry bean market classes including navy, black, pinto, great northern, small red, kidney and cranberry bean are widely grown in Canada. Genes providing resistance to CBB, anthracnose (Manitoba and Ontario only) and BCMV were transferred to these bean types using a backcross method in conjunction with the use of molecular markers to aid in the process. The method allowed the transfer of favourable genes for resistance to diseases into cultivars with desirable agronomic traits, like high seed yield, suitable maturity and upright growth habit. The breeders began by making a series of crosses between the bean germplasm lines acting as the source of the resistance genes and the high performing cultivars. The progeny of these hybridizations were then "backcrossed" over many generations to the high performing cultivar parent, with the new resistance genes carried along into subsequent generations. Molecular markers which are linked to the resistance genes were used to ensure that genes conferring resistance to CBB, BCMV, and anthracnose were present in the selected progeny. Lines which were promising for resistance to CBB and anthracnose were tested in disease nurseries in the field. The BCMV resistance was confirmed in tests conducted in growth chambers. High yielding dry bean lines with environmental adaptation, marketable seed quality, and resistance to one or a multiple of these three diseases were then selected for further trials.
As of 2009 all three research centres have resistant lines available for pre-cooperative yield trials and preliminary yield trials. At AAFC-Lethbridge, great northern, black and small red bean lines were selected for the short growing season of Alberta, Saskatchewan and western Manitoba. At AAFC-Morden, navy, black and pinto bean lines were selected for the longer growing season of the Red River Valley of Manitoba. At Harrow, a number of advanced lines of several bean market classes were selected for southern Ontario's long growing season.
It is anticipated that the lines developed in Morden and Lethbridge will be entered into the Cooperative Registration Trials in 2011, once sufficient seed has been generated. In Ontario, three navy bean lines, HR199-4587, HR200-4345, and HR193-3931 have been entered into the Ontario Cooperative Registration Trials. All three are moderately resistant to CBB and have high yields. In addition, the breeding work undertaken in Ontario has also resulted in the registration of a new navy bean line (HR177-3719) demonstrating resistance to BCMV.
Lines with moderate resistance to CBB are in various stages of development for all of the market classes of beans included in the project. Anthracnose resistance was developed in Manitoba and Ontario and some of these lines were shown to also carry the resistance gene for BCMV. Based on the performance of these lines in registration trials, new cultivars will be registered in Canada upon receiving support for registration from either the Ontario Pulse Committee or the Prairie Recommending Committee for Pulse and Special Crops.
An additional result of this breeding work is the availability of parental lines for resistance, making future breeding endeavours easier and more likely to succeed. Upon request, disease resistant lines will be provided at no cost to researchers in other bean breeding programs through the use of an AAFC Material Transfer Agreement.
The disease resistant cultivars, when available, will improve dry bean seed yield and quality and will serve as an important source of germplasm for the development of future cultivars with multiple disease resistance. Through breeding projects such as this one, reduced risk tools are provided to growers which help to protect the environment and health of Canadians while providing effective solutions for threats to Canada's food supply.
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