DEVELOPING NEW VARIETIES FOR ONTARIO
Dr. Ali Navabi believes that genetics is an important part of the solutions Ontario wheat farmers are looking for when it comes to improving crop quality and battling diseases.
Navabi holds the Grain Farmers of Ontario Professorship in Wheat Breeding in the Department of Plant Agriculture at the University of Guelph, a position that was established through a public-private partnership involving Grain Farmers of Ontario, SeCan, and the University of Guelph. He has held the position for two years, and during that time, Navabi has established a team to develop an Ontario-based germplasm pool, from which to develop new varieties of wheat. Navabi is mainly focused on the soft-red market class of wheat, because the majority of the Ontario market (90%) is for SRW and it has captured the most acreage in the province for nearly a decade.
Navabi and his team have now established a variety and germplasm development pipe-line, in which recombination of improved agronomic and quality characteristics is enhanced through introduction of new genetic diversity, crossing, and selection, and from which new wheat varieties can be extracted on a regular basis.
Two wheat diseases Navabi and his team are currently working on are Fusarium head blight (FHB) and stripe rust. In both cases, they are working to develop lines with higher levels of resistance. How they are going about it differs.
“The objective of our research into Fusarium head blight is to identify new sources of resistance and incorporate them into our Ontario germplasm-pool,” says Navabi. “To do that, we have been introducing wheat germplasm from different places in the world where Fusarium is being studied. There is nothing that offers complete resistance; there are only moderate levels of resistance. Our intention is to bring those moderately resistant varieties from different parts of the world and use them as parents in our crossing program. There is the potential to pyramid resistance genes from different sources into a common source.”
Navabi and his team are involved in a Genome Canada project led by researchers at the University of Saskatchewan. As part of this research project, a PhD student in Navabi’s team (Harwinder Singh Sidhu) and a post-doctoral researcher (Dr. Mina Kaviani) are working to develop new breeding tools (DNA marker tools) that plant breeders can use in the future to breed for resistance against FHB. Navabi says his team is first trying to find an association between the phenotype (the level of resistance) and the genotype, basically identifying what parts of the genome of wheat is contributing to resistance against FHB. Based on this information, they will then be able to develop novel breeder-friendly tools to select for high levels of resistance, even in the absence of disease.
FHB has a long history in Ontario, but stripe rust is a relatively new problem for Ontario wheat farmers. In 2016, a high level of stripe rust was seen in the southwest. Navabi says there are two different theories as to why – a new race of the disease that can tolerate higher temperatures, and the mild winter allowed the disease to overwinter higher north which meant a shorter distance for it to travel to us (stripe rust is a highly mobile pathogen).
When Navabi saw the rust in his breeding nurseries, it was an opportunity to impose selection to find resistance against stripe rust. Every line they had planted in their fields was screened for their level of infection and they identified those that were resistant.
“The difference between stripe rust and Fusarium head blight is that with stripe rust there are wheat breeding lines and varieties with complete resistance or with negligible disease severity. That is a genetic mechanism, so breeding can develop lines that are highly resistant to stripe rust,” explains Navabi. “This means farmers will be able to avoid the need for fungicide as far as stripe rust is concerned.”
Navabi and a postdoctoral researcher (Dr. Mitra Serajazari) are conducting a study of the stripe rust isolates they collected in their field, in order to identify the resistance genes that are effective against the race of pathogen in southwestern Ontario. The preliminary results of this work indicates that there are a number of resistance genes available to them that can be used against stripe rust and they are making sure those genes are in the material they are developing.
TRAINING FUTURE WHEAT BREEDERS
The training of graduate students is an important aspect of the professorship in wheat breeding. Five graduate students are currently conducting research under Navabi’s program.
“My target is to have a public breeding program, and I emphasize the word public, in Ontario that develops new varieties for farmers, studies the genetics of important traits, and trains graduate students,” says Navabi.
For example, graduate student Alex Whittal has characterized a diverse set of wheat varieties (about 200) for vernalization and for the photoperiod response they may have. This research supports another aspect of Navabi’s breeding program which is understanding the mechanisms of environmental adaptation in wheat and potentially the development of winter hardy spring wheat lines. The study included some of the winter-hardy spring wheats developed by Dr. Robert Graf at Agriculture and Agri-Food Canada in Lethbridge, Alberta. Whittal’s study has characterized these wheat lines along with Ontario-adapted wheat varieties to understand their vernalization and photoperiod response, the two mechanisms that significantly influence adaptation of winter-grown cereals. If there are spring wheat varieties that can be grown during the winter that don’t require the vernalization period it can significantly speed up the breeding cycle.
The professorship has also allowed Navabi the opportunity to introduce international development work into the Guelph breeding program and tap into funding sources that would not otherwise have been available.
“Two years in we have enough evidence this was a great idea and a great example of a public-private partnership. It was the reason we could access additional research funding from the provincial and federal governments,” says Navabi. “If we didn’t have this professorship or this partnership those research dollars wouldn’t come.” •