Arising the Falling Numbers Rapid Test with Drs. Hauvermale and McCubbin

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Low falling numbers FAQ
“The upsides of a Falling Numbers immunoassay rapid test with Dr. Hauvermale”

Contact information:

Dr. Amber Hauvermale: WSU Department of Crop and Soil Sciences,
Dr. Andy McCubbin:

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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.

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I have three guests today: Dr. Amber Hauvermale, Dr. Andy McCubbin, and Jack Kelly. Amber is a research assistant professor in the Department of Crop and Social Sciences at WSU with expertise in molecular biology, protein biochemistry, seed physiology, and hormone signaling. Prior to getting her Ph.D. at Washington State University, she worked in industry and has always been involved in projects occurring at the intersection between basic and applied research. In her current role, Amber is focusing on the physiological mechanisms that contribute to low falling numbers in wheat and she has been developing a new rapid immunoassay for low falling number detection.

Andy is an associate professor in the School of Biological Sciences at WSU with expertise in molecular biology, protein biochemistry, and a broad background in plant reproductive biology. He received his bachelors of science and a Ph.D. in botany from Reading University in the UK before coming to the U.S. in 1994. After postdoctoral research at Penn State University, he joined WSU in 2001, and he designed the peptides used to generate antibodies for use in a new rapid immunoassay for low falling number detection and is assisting with attempts to identify proteins specific to particular physiological mechanisms that contribute to low falling numbers in wheat.

And Jack is a first-year master’s student working under Dr. Hauvermale with a focus on proteins involved in low falling number events. He graduated from the University of Notre Dame with an undergraduate degree in biochemistry and a minor in bioengineering. Jack is excited to be working with Amber to develop rapid tests for low falling number detection.

Hello, Amber.

Dr. Amber Hauvermale: Hi, Drew. It’s good to be here.

Drew Lyon: Hello, Andy.

Dr. Andy McCubbin: Morning.

Drew Lyon: And Jack, good to have you here.

Jack: Hello.

Drew Lyon: Okay, Amber, I know we’ve talked about falling numbers before in previous episodes, but for those who maybe haven’t heard those episodes, I wonder if you can tell us what a falling number is and what the current method is used to measure falling number?

Dr. Amber Hauvermale: Sure, Drew. So, a falling number is literally the time that it takes in seconds for a plunger to fall through a test tube of wheatmeal gravy. And the test that’s used to measure that is called the Hagberg-Perten Falling Numbers Test. It was developed in the 1960s and it was originally used for baking.

So, what the test does is it indirectly measures alpha amylase, an enzyme that degrades starch, and in baking you actually need a little alpha amylase for good breads and cakes and cookies, but if you have too much of it, it can actually lead to poor end-use quality–so, breads that fall, sticky noodles, etc. So, that was originally what the test was developed for and it has since been adopted by the grain industry at receival stations for setting a threshold for quality prior to export.

So, the falling number test is now used in addition to baking to determine what the quality of grain is as it moves through the grain chain through to export terminals and then to our overseas markets in the Pacific Northwest.

Drew Lyon: Okay. So, that’s been around almost as long as I have, and that’s a very long time. So, why is there an effort now to develop a new rapid test? And when did that effort begin?

Dr. Amber Hauvermale: So, there have actually been people working on alternatives to this test for a long time. In our neck of the woods in the PNW, we actually had efforts back as early as 2010 and then more recently we had a new push because we had a large falling number event in 2016. It wasn’t just an isolated or regional event; it kind of occurred everywhere. And so, that kind of renewed the effort for going back to a test that could basically return information about end-use quality faster than the current test.

And one of the reasons we need that is because while the falling numbers test works well in a laboratory setting or perhaps even in a baking lab setting because of its cost and because of the size of the equipment, it can’t easily be deployed to, you know, elevators, grain elevators.

Basically, what happens is that sets up a scenario where if you have a low falling number event, you know, the people that are moving the grain through the grain chain won’t know until days or weeks after that grain has moved on and been blended. So, we like to say it’s sort of like the horse has already left the barn scenario. And so that’s another reason why we wanted to develop something that could be deployed for more rapid use and detection.

Drew Lyon: Okay. And Andy, when did you come into the project?

Dr. Andy McCubbin: End of 2017.

Drew Lyon: Okay.

Dr. Andy McCubbin: So, about six years now.

Drew Lyon: All right. And what’s your role been in the project?

Dr. Andy McCubbin One of the big issues with the Hagberg-Perten Falling Number Test is that it is based on enzyme activity, and enzyme activity is very susceptible to altitude and temperature, so it’s not always measured the same way in different places. So, one alternative way is to use antibodies to try and measure protein levels directly. You need specific antibodies so I was brought in as someone who’d worked on alpha amylases before to actually work through the amino acid sequences of alpha amylases in wheat and try to identify regions which might be good to make antibodies to.

Drew Lyon: Okay, so that’s your biochemistry background. Okay, very good. So, both of you are involved in this FFAR project trying to address this. What are the overarching objectives of that project and where are you at in it so far?

Dr. Amber Hauvermale: So, yes, we were awarded a Foundation for Food and Agricultural Research (FFAR) grant in 2022. There are six primary objectives. Objective one is basically to take the work that Andy and I and others did–Camille Steber did–prior to the awarding of this grant to take the rapid test through to commercialization. The second is to use historic varieties and to evaluate the use of the rapid test, you know, in real world settings at the variety trials. The third objective is to use proteomics to develop new markers that are going to hopefully help us better understand the physiology of LMA and PHS more specifically. The fourth is to develop an early warning system, so a way to predict where and when we may have low falling number events. And then the fifth is for evaluation of the next generation of rapid tests that are going to be specific for LMA and PHS. And finally, the sixth is to develop a really robust extension network that helps to kind of tie all of the pieces together here in the industry and also with all of the other people that are working outside of our little FFAR network on this problem.

So, this has been a really large effort with a lot of people and hopefully over the next several months, we’ll get everybody that’s involved in this project on to do one of these to kind of talk about their roles as well.

Drew Lyon: Okay. It’s no small task to try to change a practice that’s been around since the 1960s [and] industry’s bought into it. What makes you think you can change their mind? How much better is this test, I guess, than the current one? Because I’ve heard the, you know, the lack of consistency between testing sites–maybe due to what Andy mentioned, the elevation and temperature–this won’t have those problems. Or I guess, how do you overcome all the obstacles of stasis, you know? This is what we’ve been doing forever, how do you get a whole industry to change?

Dr. Amber Hauvermale: Well, I can tell you that the approach that we’re taking is not to try and change the whole industry all at once. It’s been critical for us to partner with early adopters, people who have been pushing for this effort since the beginning. So, we have partnered with several of those folks: Highline Grain Growers, the McGregor Company, the Wheat Marketing Center. These are all people that have recognized the need for a new way of doing things and who are going to be our partners in the next step, which will be validation of the new rapid test that will be coming out this summer.

So, one of the other things that we’ve talked a lot about internally in our group is the need for making sure that the language that this new test speaks is something that’s consistent with what the industry understands. This was one of the ideas that Andy and Camille came up with, basically having this thing report out an immuno falling number.

Drew Lyon: Okay. Andy, can you discuss that a little bit?

Dr. Andy McCubbin: Yeah, essentially it’ll calibrate immunological kits so that they represent a particular falling number as closely as possible.

But there is a lot of desire in the industry for change. A lot of people do not like the falling number test. We’re trying to carefully move in there and make sure we come up with an alternative which is more accurate and more reproducible.

Drew Lyon: So, Jack, when did you start on the project? You’re a new M.S. student, so I assume it’s rather recent.

Jack Kelly: Yeah, so, I started at the beginning of last summer. I hopped on to help Amber kind of perfect and develop a second generation of antibody tests, as well as ensure that the first generation actually worked.

Drew Lyon: Okay. And your skill set or what you’ve been charged to do is to use proteomics to do what?

Jack Kelly: Yeah, so, proteomics–it’s kind of the same family as all the other -omics, transcriptomics, genomics–and it’s basically the study of whatever comes before the -omics, kind of broad picture. So, in this in this case I’m looking at the protein profiles of the wheat seeds that are affected by pre-harvest sprouting or late-maturity alpha amylase with the goal being I want to identify proteins that are highly expressed in one but not the other.

And so, those will become the protein targets for future generations of tests.

Drew Lyon: Okay. So, the idea is trying to decide which is late-maturity alpha amylase caused and what is pre-harvest sprouting caused. Is that the idea?

Jack Kelly: Yeah. What proteins are unique to one and not the others, and can we use that to detect them out in the field.

Drew Lyon: What’s different about the starch or the grain that has pre-harvest sprouting versus that that has late-maturity alpha amylase. Is there a reason to segregate the two?

Jack Kelly: Yeah. So, there’s some anecdotal evidence that indicates that LMA may be salvageable where PHS isn’t. And so, this is just giving growers more options for management strategies that they can use because right now the current test really doesn’t let them do anything like that.

Drew Lyon: Okay. The current one can’t differentiate between the two, so just more information than they had before.

Jack Kelly: Yeah, more information, and then if new stuff comes out about the differences between them, we can act on it.

Drew Lyon: Okay. So, you just started last summer, when do you anticipate graduating?

Jack Kelly: Hopefully next year; we’ll see how it goes. [laughter]

Drew Lyon: [It’s] always a bit of a challenge to get it all wrapped up, but it’s really neat that you’re involved in such a wide-impact type of project because it’s not just your little thing–it has to fit into this whole idea, which will give you a really good sense industry wide and how, as Amber likes to work on that intersection between basic and applied research, that’s a nice place to be, I think.

Jack Kelly: Yes, it’s been a challenge, but I enjoy it a lot.

Drew Lyon: I guess I asked Andy when he started on the project. Amber, I didn’t ask you that question yourself. How long have you been involved with this?

Dr. Amber Hauvermale: So, I started in 2018 and, you know, basically taking what Andy had developed and then working it through the lab to, you know, once we got antibodies back to validate them for use in a rapid test and an immunoassay, making sure that they performed the way that that we hoped that they would, meaning that they were specific for alpha amylase and that they could be worked in pairs, used in pairs, and then that they would be suitable and compatible for an ELISA (enzyme-linked immunoassay).

And then once we went through that process in-house, we then turned that over to our industry partner, EnviroLogix, so that they could do the same sort of validation using their technology. And we partnered with them in 2021, I believe. And so, they’ve been working with us this entire time.

Drew Lyon: Okay. Any updates on when beta testing will begin on this new test? Is that about to happen here in this coming season or when is that going to occur?

Dr. Amber Hauvermale: Actually, I think it is. I know we’ve talked about this both times that we’ve done these podcasts. If all goes according to plan, we will be heading out to Portland in May or the end of April to go break the test, in essence, that EnviroLogix has created–basically to put it through its paces.

But the plan is to have tests here in the Pacific Northwest beginning soon after that. So, it’s an opportunity for me to go and be trained and then we’ll have one here on campus at WSU. And then we are strategically placing them with our FFAR partners this summer with the intention of starting to beta test this season.

Drew Lyon: Okay, so they would use this immunoassay kit and also the Hagberg-Perten falling number test and compare and see how close they are? Is that the idea?

Dr. Amber Hauvermale: That’s the idea. Yes.

Drew Lyon: Okay, very good. Well, I think we’ll have to have you back on a year from now to find out how that all works, because this does sound like it could be a real positive change for the industry [to] let them do a better job of segregating wheat and keeping low falling numbers out of the game. [It] might also help, I think you’re hoping that it helps wheat breeders as well in their process, so a real interesting and positive impact and we’d like to keep up to date on that.

Amber, Andy, Jack, thank you for being my guests today. I enjoyed having you on.

Dr. Amber Hauvermale: Thank you.

Dr. Andy McCubbin: Thank you.

Jack Kelly: Thank you.


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.