Growing Resistance to Stripe Rust with Dr. Xianming Chen

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USDA ARS Wheat Health, Genetics, and Quality Research Unit
WSU Wheat and Small Grains stripe rust information

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Dr. Xianming Chen,

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Episode transcription:


Drew Lyon: Hello, welcome to the WSU Wheat Beat podcast. I’m your host, Drew Lyon, and I want to thank you for joining me as we explore the world of small grains production and research at Washington State University. In each episode, I speak with researchers from WSU and the USDA-ARS to provide you with insights into the latest research on wheat and barley production.

If you enjoy the WSU Wheat Beat podcast, do us a favor and subscribe on iTunes or your favorite podcast app and leave us a review so others can find the show too.


My guest today is Dr. Xianming Chen. Xianming is a research plant pathologist with the USDA-ARS Wheat Health, Genetics, and Quality Research Unit in Pullman, Washington. He joined ARS as a postdoctoral geneticist in 1997 and has been in his current position since 2000. He has worked on stripe rust for 40 years and is currently leading the ARS project on enhancing control of stripe rust of cereal crops.

His team conducts basic and applied research for better understanding the epidemiology of stripe rust and developing resources and technologies for improving integrated management of the disease. Hello, Xianming.

Dr. Xianming Chen: Hello, Drew.

Drew Lyon: How are you doing today?

Dr. Xianming Chen: Good.

Drew Lyon: Glad to have you on the show today. So, your research program received $90,000 from the Washington Grain Commission in the current fiscal year. What does this support allow you to do that wouldn’t be possible without the funding?

Dr. Xianming Chen: Yeah. Washington Grain Commission does support our program this year for $90,000. That is very essential and very important for our program. We use these funds to hire a Ph.D. student and our post-doctorate to work on the resilience of wheat to stripe rust.

Drew Lyon: Okay. And that wouldn’t be possible without these funds?

Dr. Xianming Chen: That’s right. Without it we cannot have these two people to work in our program. It is very important for our program.

Drew Lyon: Very good. So, why does your team focus on stripe rust? What’s so important about stripe rust?

Dr. Xianming Chen: Yeah, stripe rust is caused by a fungal disease. This fungal pathogen and this disease has been very destructive, as you know, all across the world, especially in the Pacific Northwest, because the Pacific Northwest has a very conducive climate and the weather conditions and also crop systems to have the disease occur almost every year and do very severe damage.

Drew Lyon: Okay. I was in western Nebraska for a lot of years, and I remember Steve Baenzinger, the wheat breeder–one year, I think it was 2000–we had stripe rust and he held up this plant [and said] “This is stripe rust. Take a look at it–you won’t see it in another 10 years.” So, it wasn’t very common in the Great Plains, but here, like you say, the weather conditions are just conducive to having it almost as an annual problem. Is that right?

Dr. Xianming Chen: That’s right. Actually, this stripe rust has also become a national problem since the year 2000. Before the year 2000, stripe rust would just occasionally occur–you know, in a place like a Nebraska and it was treated as a curiosity disease. But since the year 2000, a stripe rust has also caused a very severe damage in the Great Plains and in the eastern states.

Drew Lyon: Yes. As I recall, he said that. And then about every other year after that, we had stripe rust problems because the race had changed. So, important disease, particularly here in the northwest. It hasn’t been a big problem the last couple of years because we’ve kind of been dry, but the years before that, it has been a major problem and growers are really focused on it.

Dr. Xianming Chen: Yeah, that’s the case. Yeah. Because stripe rust really likes very wet and cool conditions in the spring, and later spring, and also early summer. So, when the weather is very dry like in 2021 and hot in that year, stripe rust was very low and a less[er] problem. And similarly like this year, we had a very dry weather conditions but the weather was not as hot as 2021, so this year stripe rust was also very light.

Drew Lyon: Okay. So, the conditions that actually make this good country for growing wheat also makes it a good area for growing stripe rust.

Dr. Xianming Chen: That’s right. Yeah, because each year that we do not have a stripe rust problem, it means the [stripe rust is] very low just like 2021 and this year. So, we hope we have good yield potential and we can also get stripe rust under control.

Drew Lyon: Right. So, the years we can really get good yield are the years and you [have] to be concerned about stripe rust.

Dr. Xianming Chen: That’s right. Yeah.

Drew Lyon: Okay. So, what has your team accomplished in the recent 10 years and how have these accomplishments contributed to stripe rust management?

Dr. Xianming Chen: Yeah, that’s a good question. Because our program [focuses] on stripe rust, we mainly are doing research to improve our understanding of the epidemiology of the stripe rust and also improve the resilience in commercial varieties and also we develop[ed] an integrated management strategy to reduce stripe rust to a minimum. So, with these three objectives.

For the first, we monitor stripe rust population especially [with new] variety releases. So, every year we collect samples from [the] Pacific Northwest, especially Washington state, and also we receive samples from other states to test if these samples are susceptible and different varieties that each carry different resistance genes. So, therefore, we can clear out of the stripe rust resistance and use this information with selected releases from different groups for screening germplasm.

Second objective is screening thousands and thousands of wheat and barley materials for stripe rust resistance and these materials are mostly from breeding programs. With our screening data, we have supported the breeding programs to release resistant varieties in the last 10 years. With Washington State alone, we have released more than 20 wheat varieties and some barley varieties, together with the breeding programs.

And for the integrated control, every year we conduct fungus testing and also commercially grew varieties with yield loss estimation studies. With this information, we can tell when you grew this variety, what’s the potential yield loss, and a certain line of the stripe rust. So, that’s giving growers specific recommendations when you grow certain varieties about whether you should spray with the fungicide or not. So, that is what we’ve accomplished in the last 10 years and more.

Drew Lyon: I know I’ve sat in on a few wheat variety release committee meetings and your reports on stripe rust are in every one of those variety releases and it’s an important piece of information used on whether a variety is going to get released or not get released, so I know they look at that information very closely. And I think in a lot of–like on the wheat variety selection tool, they all have a rating for stripe rust resistance and I assume they rely heavily on the data that your group generates.

Dr. Xianming Chen: Yes. Every year we test these variety trial nurseries and in our greenhouse with multiple releases in the seeding stage and in the adult plant stage, so therefore we can determine whether the varieties have a specific resistance or non-specific high-temperature adult plant resistance. We use this information so we can gauge whether we should release these new breeding lines, the ones that are released, and we also have the information for growers to use to see whether should they use a fungicide or not.

Drew Lyon: Okay. I know you put out fairly regular reports during the growing season on what you’re finding out in the field that can help growers–and Extension, we use those reports quite a bit to put out reports [about whether] stripe rust is low or stripe rust is really bad, [what to] take a look at. So, I think those that’s another thing your team does, right? They go out and they actually monitor how stripe rust is doing across the region.

Dr. Xianming Chen: Yes. Thank you. Our program is monitoring the stripe rust in the fields mainly starting from November and after winter, we start up again. Some years [are] early—start in February– normally is March to watch for stripe rust at different locations. With that information, we can tell the growers whether stripe rust will be make a problem or not.

And also our program in the past has developed a set of forecast models. We use these models to give the growers early prediction–a warning–about stripe rust. That data is based off of weather data and our historical variety yield loss data to predict the stripe rust in early January and a second time in early March. It is a critical time in March for use or not-use of an early application of fungicide to control stripe rust.

Drew Lyon: Okay. So, is there a place growers can go to find these reports? Do you have a website where you post these? I know we use them to put out some Timely Topics, but if somebody wanted to go actually find your actual report, is there a way for them to do that?

Dr. Xianming Chen: Yes, you can get them two ways. We send out these immediately to growers and we share with their community. We also put out these stripe rust updates and our disease data, nursery data on our website called We also send these to other Extension programs for making this available to growers.

Drew Lyon: Yeah, okay, very good. We’ll make sure we put that URL in our show notes so people can find it.

Dr. Xianming Chen: Thank you.

Drew Lyon: So, what would you like to accomplish in the near future?

Dr. Xianming Chen: You know, stripe rust is an old disease in this area. But these days we cannot eradicate it because the pathogen can not only grow on wheat and on barley, but also can survive on grasses. So [we] always have stripe rust somewhere in the nation in this area. So, therefore, this disease, we just need to manage the disease to minimize yield loss. But we cannot eradicate it like some other diseases. So, therefore, we need to continually monitor the disease and use what’s currently available—all the information and the knowledge produced from our program and other programs–to get the yearly management for reducing that damage.

And also, as you know, stripe rust is mainly controlled by using resistant varieties. These resistant varieties develop take new genes, to edit genes together, therefore these things take time. Our program has identified more of these–in recent years– development markers for the breeding program to use. For the breeding material we need to do screening for resistant to stripe rust to make sure that’s not very susceptible variety.

Drew Lyon: Okay, so it’s a pest. It’s going to always be with us and it’s always changing, so it requires continuous monitoring and new information generated almost on an annual basis.

Dr. Xianming Chen: Yes. And also I’ll give you more numbers, the stripe rust was able to cause over 90% yield loss of very susceptible variety. For the last 20 years, the average of the yield loss for the susceptible variety is over 40%. And the breeding program to develop the current commercially used varieties was able to reduce this 40% yield loss to 8%.

So, that’s a great achievement in the last many years. But this 8% yield loss still [is a] very big number. For Washington alone, that’s over $100 million in yield loss if we do not use a fungicide at all to control the stripe rust. So, therefore, our future goal is to try to reduce a potential yield loss for a commercially grown variety from 8% to below 1% or even to zero. That is our goal we are trying to accomplish with our program and collaborate with the breeding programs and Extension programs.

Drew Lyon: Okay, very good. That’s a good goal to have because I know in most years it’s a pest that growers are thinking about all the time, especially come springtime. That’s the big pest. So, what do you like to say to growers regarding stripe rust management?

Dr. Xianming Chen: You’ll see in the last three years [that we’ve had] two years that stripe rust was very low because of very dry and hot conditions in the later spring and early summer. So, that may make the growers think “Oh, stripe rust could be gone!” But the reality is stripe rust [is] not gone.

And also based on the current situation, we sort of predict the stripe rust could be a problem for next season. And the reason for that [is] because we had quite good moisture in August and September that can make these volunteers to grow after harvest. So, there is stripe rust that can survive on this volunteer to survive the winter. And also based upon current weather forecasts–because El Nino has come back again–long-term forecasts for this winter in the Pacific Northwest will be warmer and dry, but especially warmer. Warmer conditions allow the stripe rust to survive in plant tissue. That means after the winter, in the next spring, stripe rust could have high accumulation in wheat plants and the grasses and may start the disease epidemic earlier next spring.

So, therefore, the growers need to keep that in mind. And if you have not planted winter wheat, please select the resistant varieties to grow or keep stripe rust as a top priority. And for the next spring, select a spring wheat variety [that is resistant].

Drew Lyon: Okay, so your message is don’t be complacent. Just because we haven’t had much lately doesn’t mean anything for this coming year.

Dr. Xianming Chen: That’s right. Yeah.

Drew Lyon: Alright. Well, Dr. Chen, I appreciate you sharing your insights on stripe rust with us. Sounds like you’ve made a lot of progress, and yet you still have a goal of making even more. Thanks for being my guest today.

Dr. Xianming Chen: Yes, thank you.

Drew Lyon:

Thanks for joining us and listening to the WSU Wheat Beat podcast. If you like what you hear don’t forget to subscribe and leave a review on iTunes or your favorite podcast app. If you have questions or topics you’d like to hear on future episodes, please email me at drew.lyon — that’s — ( You can find us online at and on Facebook and Twitter [X] @WSUSmallGrains. The WSU Wheat Beat podcast is a production of CAHNRS Communications and the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.

I’m Drew Lyon, we’ll see you next time.


The views, thoughts, and opinions expressed by guests of this podcast are their own and does not imply Washington State University’s endorsement.