What is in this article?:
- California wheat growers challenged by stripe rust
- Worldwide epidemic
- Gene breakthrough
- California wheat crops looks good as harvest begins.
- However, stripe rust attacking more resistant varieties.
- Genetic breakthrough by UC wheat breeder offers hope of introducing stripe rust resistance into older, new varieties.
“Stripe rust is a worldwide epidemic,” said Wright, that often renders newer, more resistant varieties unwanted after just a few years because of the often rapidly growing susceptibility to stripe rust.
Earlier this spring Jackson reported “much” commercial acreage of Joaquin has been severely affected, even in instances when two fungicide applications were made.
Stripe rust has spawned considerable controversy. The university’s recommended approach in dealing with the problem is host plant resistance. Commercial seed companies say fungicides can keep a variety viable longer. Wright admits that growers can justify fungicide treatments on high yield, high quality wheat susceptible to stripe rust in these times of high grain prices.
“This year is when that happened with certain varieties” like Joaquin, Wright said.
Although breeders are rapidly developing stripe rust resistant varieties, Wright admits there is a “short list” for now of substitutes for the high yielding varieties susceptible to stripe rust.
However, the list is likely to get longer due to the work of UC Davis wheat breeder Jorge Dubcovsky who has identified a combination of stripe rust resistant genes called Yr5/Yr15 he has successfully introduced into wheat varieties.
Jackson reported that several new varieties containing the Yr5/Yr15 combination of genes were largely unaffected in the nurseries, where he found high levels of stripe rust in other varieties.
At a recent UC Davis wheat field day, Wright said Dubcovsky displayed a new Blanca Grande prodigy with the Yr5/Yr15 gene giving it stripe rust resistance. This could bring back the popular variety.
“It is a major breakthrough — a big change in the way we deal with stripe rust,” Wright said.