Resistant varieties are on the way, but it’s still going to be several years before they reach producers’ fields
The 2023 Pulse Variety Seminar was a new virtual webinar that replaces the Saskatchewan Pulse Growers annual Select Seed Grower meeting. The seminar was open to everyone, free of charge.
The Jan. 17 webinar updated members on new varieties and initiatives in the pulse crop industry, including new information on root rot developments.
Sabine Banniza, a plant pathologist at the University of Saskatchewan’s Crop Development Centre, has worked on pulse crop diseases for 20 years. She summarized recent root rot developments for attendees.
Banniza told the audience that new fusarium strains now affect peas, lentils and chickpeas.
“In the field, you often have a mix of different disease symptoms at the same time and this makes it more difficult to identify the exact problem,” said Banniza.
“Based on pathogenicity patterns, it appears that fusarium avenaceum is the most virulent. So our breeding efforts right now are focused on resistance to fusarium avenaceum. This disease gives a reduction of the shoot biomass and the root mass. Also discolouration right at the soil level.”
In her discussion of partial resistance to Aphanomyces root rot in peas, she introduced major QTLs (quantitative trait loci), an approach for studying genetically complex forms of plant disease resistance. Major QTLs represent areas on the chromosome associated with certain complex traits.
“In the pea genomes, there are many QTLs associated with resistance. That makes breeding more complex than when you’re dealing with just one gene, for example. We were very lucky that our French colleagues have been working on this problem for many years.”
Banniza said the project focuses on the two QTLs with the highest probability of finding a solution. Her team worked with University of Saskatchewan plant breeder Tom Warkentin to optimize resources.
“Tom got together with my team to launch an intensive back-breeding program to improve Aphanomyces resistance. There were two CDC varieties he used to transfer resistance. They were crossed three times with the CDC parent to ensure the new variety maintained the positive traits of the CDC parent.
She points out their French colleagues provided marker assisted selection, which allowed the team to screen for molecular markers to see if the QTLs are still present in the offspring. They only proceed with offspring that contained all the markers.
“When we finally looked at the results, it seems we did something right. Tom has selected the most promising lines and they went into trials in 2021. Last year, he produced breeder seed for those lines. We are intending to enter them into trials this year to be tested another two years.”
The long wait is simply part of the process, Banniza said, explaining that it would have taken even longer had not the French generously shared the breeding they began in 1996.
“They began this work in 1996. It took them until 2020 to release the first variety with Aphanomyces root rot resistance. That’s 24 years from identifying the resistance until they release a variety.
“We started our back-cropping program in 2015.With some luck, we can register our first variety in 2025.”
The link to the entire seminar is at https://saskpulse.com/news-events/events/2023-pulse-variety-seminar/.
