Midge-resistant varieties begin the trek to market

Source: Saskatchewan Agriculture and Food

It’s taken 15 years so far – and the wait isn’t over – but four wheat varieties with resistance to wheat midge have now been recommended for registration.

Developed by wheat breeders from Agriculture and Agri-Food Canada in Swift Current and Winnipeg, three of the varieties are in the Canadian Western Red Spring wheat class, and one is in the Canada Western Extra Strong wheat class.

The research was supported by the Western Grains Research Foundation in Saskatoon. Lanette Kuchenski, Executive Director of the Foundation, says it will be a while before the new varieties become available.

“What happens now is the line is licensed to a seed distributor,” said Kuckenski. “They will begin increasing the seed, and it will take two to four years to increase it to the point where it can be made available for general use.”

The midge-resistant trait was found in older American soft red winter wheat varieties. It has taken this long to move the trait into spring wheat varieties that also have the superior yield and other traits sought by Western Canadian farmers.

The resistance is the result of the induction of two naturally occurring compounds in the wheat kernels, ferulic acid and p-cumaric acid. With these compounds present, wheat midge larvae are not able to develop when feeding on the immature kernels.

Kuchenski says that one of the challenges is to intentionally keep the new varieties from being 100 per cent midge resistant.

“What we’re trying to do is ensure that this one gene is somewhat protected from the wheat midge gaining resistance to it,” she said. “So we’re actually going to have to work with the CFIA (Canadian Food Inspection Agency) to ensure that we can put in between five to 10 per cent of non-resistant variety.”

The objective of maintaining some non-midge resistant plants within the varieties is to extend useful life of the resistant gene.

“What that’s going to do is allow the insect to survive in relatively small numbers and have a very minor impact on yields and grades,” said Kuchenski. In this way, there will be less pressure on the wheat midge population to develop tolerance to the resistant wheat varieties.

By holding back reproduction of the midge that feed on resistant plants, the impact of the new varieties should last another 10 to 20 years before the midge develops its own adaptation and learns to prosper on the resistant wheat.

Kuchenski says it is important to protect this technological advance because of the substantial investment required to develop the resistant varieties.

“It’s extremely costly to breed for this resistance, because of the length of time and the amount of resources you put in before you see any type of light at the end of the tunnel,” she stated. “What we want to do is try to protect the gene a little bit longer than we have in the past, which will give us the time to look for other alternative resistant genes.”

The Western Grains Research Foundation uses a wheat check-off to fund the research, as well as government support for the projects.

According to Kuchenski, the midge resistant varieties are important for producers, not only because they will mitigate losses, but also because management of wheat midge infestations can be difficult.

“The only defence that producers have is pesticide application, which is costly,” she said. “It’s also really difficult to know the best time to spray for midge, and the expert resources who can help tend to be in demand all at the same time of the growing season.”

Wheat midge damage resulted in yield losses and downgrading of wheat crops, largely in the east central and northeastern parts of the province in 2006. If conditions are favourable in 2007, wheat midge are likely to be even more widespread, so producers will be waiting anxiously for these new seed varieties to become available in the future.

For more information, contact:

Lanette Kuchenski, Executive Director
Western Grains Research Foundation
Phone: (306) 975-0060
E-mail: lkuchenski@westerngrains.com
Website: www.westerngrains.com