Gaining Ground

How research is helping grow the output of Saskatchewan's pulse industry

One of Saskatchewan Pulse Growers' (SPG) major research goals is making overall economic gains for the pulse industry in the province.

How does this happen?

By addressing the organization's research priorities, says Dr. Lisette Mascarenhas, Director of Research and Development.

One of these priorities is increasing the production of pulses.

"This area includes everything from pre-breeding work. to variety development, to determining how varieties that are released adapt to the environment, to honing best management practices for growers to grow the varieties that are released," she says.

Another priority is removing production constraints by addressing issues that affect and impact pulse production in Saskatchewan, including pests (diseases, insects, and weeds), nutrient management, water management, and more.

SPG regularly seeks input from industry members such as growers, agronomists, and researchers, to continually update what the constraints are, Mascarenhas says.

"We then focus on research that would help find solutions to remove these constraints," she says.

Finally, economic gains are achieved through developing new pulse crop options for Saskatchewan growers. SPG currently has a goal to develop at least one viable pulse crop option for every acre of farmland in Saskatchewan.

"We encourage growers to grow pulses because of their economic and environmental benefits, so we need to have options for them to choose from," Mascarenhas says.

These three research priority areas are all equally important, as one does not work without the other.

"lt is not just about having varieties available, it is also having agricultural practices and best management practices that growers can adopt to successfully grow them, " Dr. Mascarenhas says.

SPG is currently funding ongoing research in all three areas, aiming to provide Information that will help answer the ultimate question: how can we grow the output of Saskatchewan's pulse industry? Here is a look at some of this research.

Pre-Breeding Work

Before you can breed new, improved pulse varieties, you need to know exactly how to make them better than previous varieties. And this is where a lot of SPG-funded research begins.

For example, one of the major problems currently affecting pulse growth in Saskatchewan is Aphanomyces root rot caused by the Aphanomyces euteiches pathogen. Since it was discovered in the province in 2012, this pathogen has severely affected pea and lentil crops in the province, and there are currently no effective management options available aside from avoiding growing susceptible crops for a minimum of six years.

Dr. Sabine Banniza, Plant Pathologist at the University of Saskatchewan's (U of S) Crop Development Centre (CDC) and a Professor in the U of S Department of Plant Sciences, has been working to combat this issue for years, and has made some modest gains.

She recently completed a research project that aimed to produce Aphanomyces-resistant lentil varieties through rapid generation technology (RGT) involving wild lentil crosses. The use of RGT was a success, in that it will help speed up and fuel ongoing research that will screen for Aphanomyces resistance in the wild lentil germplasm, she says.

What is rapid generation technology?

Dr. Tom Warkentin, Professor with the Department of Plant Sciences and Plant Breeder with the CDC at the U of S, explains: "With rapid generation technology (RGT), plants are grown under conditions that result in miniature plants which flower and mature earlier than under normal growing conditions. Miniaturization is achieved by growing the plants in crowded conditions and/or by applying plant hormones that shorten plant internodes. Before the resulting seeds are fully mature, they are excised and replanted to start the next generation."

"Whatever resistance we identify will be used for crossing and then we can use the rapid generation technology for wild lentil to advance the material as quickly as possible. This will also be very useful to develop populations for the development of molecular markers for Aphanomyces resistance in lentil as quickly as possible."

Banniza's current research, which aims to integrate Aphanomyces resistance screening into RGT for lentils and peas, has also made progress developing partially resistant pea varieties. At this point they have crossed seven adapted pea varieties with partially resistant United States Department of Agriculture (USDA) pea lines developed by colleagues in the United States (U.S.) and France.

"We are very lucky that other research groups have already done a lot of the screening in peas," Banniza says. "We are miles ahead because of this, because identifying sources of resistance can be a very painstaking and long process."

Through additional funding from SPG, the team has now been able to adopt molecular markers to help identify resistant lines. They are now screening for those markers, and will advance lines to see if they have partial resistance.

"This will become the first generation of Aphanomyces-resistant varieties using one source of resistance," Banniza says.

If all looks positive, the pea lines could be entered into co-operative trials within three years, where they would have to undergo two years of testing before they could be released, she says.

This offers some light at the end ofthe tunnel for Saskatchewan pea growers. In terms of developing lentil varieties with resistance, however, we are a bit further behind.

Banniza and her team have screened a selection of lentil cultivars trying to find some resistance, and found none. They also recently screened some Iranian lentil landraces from the USDA that were identified with partial resistance, but the results have not been positive so far, Banniza says.

"It could be that our isolates are a bit more aggressive than those used at USDA when they originally screened that germplasm," she says. "We will screen the germplasm again with an improved protocol for pathogenicity testing."

One bright spot in this research, however, is that Aphanomyces is an issue currently being addressed by researchers internationally, and therefore growers stand to gain from progress made elsewhere in the world, according to Banniza.

"We know that our USDA colleagues are working in more detail on this, so we will focus more on the wild lentil germplasm while they concentrate on the domesticated lentil species. This way, we all get ahead faster."

At the CDC, breeders are also working with genomics to develop new varieties of chickpeas, a crop that has fluctuated in recent years due to weather and market conditions.

"It is still challenging for growers to produce chickpeas," says CDC breeder and U of S Associate Professor Dr. Bunyamin Tar'an. "They require dry and warm conditions and since 2010 we have been in a wet cycle. This is a crop that when you grow it, you really need topay close attention and do your due diligence."

Although there have been major improvements with some of the current varieties, there will always be work to be done in breeding chickpeas, Taran says.

One of the benefits of working with this crop is that the genomic sequencing for chickpeas was completed back in 2013, making it further advanced in this respect than other pulse crops such as peas and lentils. Tar'an is currently using these tools in his chickpea breeding program that involves genomic selection and resequencing.

"You create a population as you are training and you create a statistical model and use it to make selections into your breeding lines," he says. "Right now, we are testing it with several traits, including those that we know, to see how accurate the technique is and how much genetic gain we can get. We are still answering a number of questions but this will help us bring a better product quicker to growers."

The overall goal of the chickpea breeding program is to breed varieties that have shortened time to maturity under Saskatchewan growing conditions, and improved disease resistance. The CDC breeders are also working on improving the crop for food processing and end-use consumer markets,by improving the functionality and nutritional traits of chickpeas. 

The CDC is currently doing important pre-breeding work with lentils, aiming to diversify the cultivated germplasm available to breed new varieties. This research is important to maintaining the productivity and output of the lentil industry, which has seen an annual yield gain of more than three per cent since 2001.

Superior Varieties

At the CDC, pulse breeders are continually working on developing new varieties that have improved traits such as higher yield potential, improved disease resistance, better seed quality, and more.

Dr.Tom Warkentin is one of these breeders, focusing primarily on peas.

'We have a large breeding program on peas and the majority of germplasm testing is done in Saskatchewan," he says. "By being based here, by having a large program with diverse material, and by testing it under the wide range of conditions that are present in Saskatchewan, we are able to select material with higher yield for the growers."

One of Warkentin's current research projects Is a genomic study focused specifically on introducing new diversity into pea breeding material to improve key traits in the crop.

"By crossing then selecting with markers, we are going to put small segments of chromosomes from five different donor parents into CDC Amarillo, which is one of our recent high-yielding varieties, and then we are going to look at resulting lines in the field and determine whether they are adding something extra to the variety," he says.

The donor parents have been carefully selected for their ability to potentially add valuable traits to the new lines, including resistance to Aphanomyces and Ascochyta, higher protein concentrations, greater resistance to heat during flowering, and more.

The research will continue over the next two years, at which point Warkentin hopes to have solid leads into improved pea varieties.

"Improved varieties, or at least improved parents for breeding, may come directly out of this resource," he says.

There is also some exciting variety development work being done at the CDC with faba beans.

Although the CDC began breeding this crop decades ago, interest is currently picking up, says Tar'an.

"Because of the wet conditions we have had here in the past years, and problems with root rot, people really need alternatives in their rotations," he says.

Faba beans are especially appealing right now as they perform better in wet conditions and have partial resistance to Aphanomyces euteiches.

There are two types of faba beans, one is larger seeded with coloured flowers, which is more suited to the food market, and the other is smaller seeded with white flowers, which is a zero-tannin market class, making it a better fit for the feed market and for fractionation.

"The tannins have some negative impact for the feed market because they lower the energy to the animal, so with zero-tannin we minimize the problem," saysTar'an.

Smaller seeds are also preferable to growers, as they are easier to seed and have lower seeding costs.

The CDC is currently working on developing new breeding lines of both white and coloured flowered faba beans with small and large seed size that can tolerate drier conditions (faba beans do not do as well with dry conditions), have disease resistance (especially to chocolate spot), and that have low vicine and convicine levels, making them safe for human consumption.

Tar'an says we are not too far away from having new faba bean varieties with the low vicine and convicine levels.

"There is some potential amongst our current breeding lines," he says.

Weeds as a Constraint

One of the major issues facing all Saskatchewan pulses right now is herbicide-resistant weeds, says Dr.Chris Willenborg, Assistant Professor, Plant Sciences at the University of Saskatchewan.

"We have all seen lentil fields that look like an intercrop of mustard, but this is in fact Group 2-resistant wild mustard," he says.

Within the past five to seven years, several forms of resistance have been identified in Western Canada, including Group 2, 4, and 9 herbicide-resistant kochia.

"Group 2-resistant cleavers is also a challenge for pea growers, and Group 2-resistant kochia, stinkweed, and wild mustard are problematic in many of the lentil-growing regions of the province," Willenborg says.

In light of this, he is currently working on a research project with Eric Johnson, Research Associate with the Department of Plant Sciences at the University of Saskatchewan, looking at how to better manage the growing challenge of herbicide-resistant weeds in pulse crops, and how to use integrated solutions that improve weed control and reduce the cost of weed management to pulse growers.

An integrated approach to managing the problem is a must, he says.

"We are working on many different avenues to tackle this, including better understanding of weed seed predators and their contribution to weed control in pulse crops, improved cropping systems that would improve management of weeds, and improving operational diversity in pulse crop production through optimization of various management practices."

This research is a multi-year project that kicked off in 2016. It is too early to discuss results, Willenborg says, but he hopes that when it wraps up in 2021 they will have new information that can be immediately put into practice by growers. For now, he cautions growers to start considering longer-term, more integrated strategies to manage herbicide-resistant weeds.

"Breeding herbicide tolerance to another mode of action into a crop will buy us some time, as will stacked herbicide-tolerant traits. However, these will ultimately select for yet more resistance to other modes of action. Probably the best time to start resistance management planning was yesterday, although there is a definitely a bit of a 'it cannot happen to me' attitude or 'why worry about what is not yet ailing me?' But in reality, what we know is that an ounce of prevention now is worth a pound of cure in the long-run."

SPG is also funding other research in the area of controlling weeds, diseases, and improving agronomic practices.