Fingerprinting Chickpea Germplasm - PulseResearch
April 25, 2017
Researchers use pedigree-based genome mapping to identify chickpea DNA
Chickpea production has maintained consistent levels in Saskatchewan, however, given its susceptibility to Ascochyta blight, especially under cool and wet conditions, chickpea production is still considered risky in the province. Since Ascochyta blight may adversely affect the sustainability of chickpea production, enhanced breeding efforts are essential to develop highyielding varieties with good adaptation to Saskatchewan environments, improved resistance to Ascochyta blight, and be of premium quality.
Using pedigree-based genome mapping to identify the DNA markers for seed size, earliness, and Ascochyta blight resistance in chickpea, researchers at the Crop Development Centre (CDC), with funding from Saskatchewan Pulse Growers, completed genetic characterization and interrelationships of 124 chickpea germplasm, breeding lines, and varieties from the CDC pulse breeding program.
Dr. Bunyamin Tar’an, the lead researcher for the project, explains that this involved identifying the appropriate interrelated sets of germplasm and varieties, verifying phenotypic information, identifying a suite of robust and polymorphic molecular markers, fingerprinting the germplasm, and verifying the pedigrees. The final stage includes collating phenotypic, genotypic, and pedigree information to undertake linkage analysis.
“The information generated in this project supports breeders in genetic studies of economically important traits and in exploration and use of breeding lines and germplasm collections,” Tar’an says. “It should help breeders assess marker-trait associations and choose more quickly the most interesting genitors to cross with, and to select for their superior progeny.” This means the development of more targeted and efficient breeding of new varieties with desirable production traits.
“The chickpea breeding program has emphasized a lot on the earliness (of crop maturity) and large and bold seeds types,” Tar’an says. Chickpea is inherently a long season crop; early maturing cultivars are needed for the short growing season in Saskatchewan. In addition, large seed size Kabuli chickpeas are highly desirable for a premium price. “As such, a number of germplasm with early maturity and large seed size were used in the earlier crossing.”
“Unfortunately these lines are also highly susceptible to Ascochyta,” he adds. “As a result, while improvements were made on the earliness and seed size, unfortunately the progeny became susceptible to Ascochyta.”
Another major finding of the research was the identification of the genetic basis giving rise to resistance to imidazolinone (IMI) herbicides in chickpea.
“We found out that a single nucleotide change led the resistance to IMI herbicide in chickpea,” Tar’an says. “We then developed a DNA marker targeting this single nucleotide change for use in selection for herbicide resistant chickpea breeding lines.”
This means that instead of growing the plants for a month or more then spraying them with the IMI herbicide, the researchers can now just scratch the cotyledon, extract the DNA and run the assay with 100 per cent accuracy in identifying the seeds, and thus the plants, that are resistant to IMI herbicides. Overall, this means quicker delivery of IMI resistant cultivars to growers.
“This protocol has been routinely used in our breeding program,” Tar’an says.
SPG Investment: $242,018
Project Length: 4 years
Dr. Bunyamin Tar'an - Chickpea Breeder, Crop Development Centre, University of Saskatchewan
Dr. Andrew Sharpe - Genomics Scientist, National Research Council
Dr. Tom Warkentin and Dr. Bert Vandenberg - Crop Development Centre, University of Saskatchewan