Intro: This is a GRDC podcast.

[00:00:12] Sally Maguire Hello, I'm Sally Maguire. Long coleoptile wheat varieties have the potential to deliver increased yield and therefore profit to Australian growers. That's why GRDC is investing in extensive research to futureproof the crop. Steve Simpfendorfer from the New South Wales Department of Primary Industries, is part of the nationwide project team and his area of speciality is looking at how disease interacts with deep sowing.

[00:00:40] Steve Simpfendorfer I'm a cereal pathologist with the department and involved in the long coleoptile wheat, along with two main other pathologists. So Jonathan Anderson with CSIRO WA and Belinda Sommer in South Australia who's also with CSIRO. So what we're on is to look at all the different facets of adopting long coleoptile wheats within a cropping system. There's work going on with nutrition, herbicide interactions, but we're interested specifically in what it might do for different pathogens both beneficial but might be an issue as we adopt this technology with the farming systems. So our real aim is to identify it and develop workarounds so it doesn't become a barrier. So disease doesn't stop growers adopting this technology on farm.

[00:01:17] Sally Maguire So from the outset where the initial concerns around the aspect of deep sowing and disease?

[00:01:23] Steve Simpfendorfer Yeah. So certainly when you try to adopt something new like this, you know a fair bit about a lot of pathogens and the one we were mainly worried about was common root rot caused by a fungus called Bipolaris sorokiniana and it's got a thick walled spore which survives in the soil and its main infection point is the coleoptile. And that thickens to become the subcrown internode. And so the whole concern there was if we adopted long coleoptile wheats sown deeper we'd end up with a longer coleoptile and therefore subcrown internode and more probability of coming in contact with those spores in the soil and increasing our incidence of common root rot infection. Certainly up here in the northern region where we do get this often in combination with crown rot, we know that we've run into problems with common root rot in our systems when we have sown deeper in some situations. So common root causes ill thrift. It attacks that subcrown internode and really reduces the efficiency of the primary root system to extract water and it just looks like ill thrift, it looks like the crops not growing they're not growing as well as they can, so very hard to diagnose. Very distinctive blackening of the subcrown internode is the main symptom. But yes, certainly that was the main one we're concerned about when we went in. But we'll talk about in a bit. We found some quite interesting interactions about some of the things which were quite beneficial to growers.

[00:02:36] Sally Maguire So can you tell us a bit about your methodology in this first growing season of this investment?

[00:02:41] Steve Simpfendorfer Certainly in the pathology space, there hasn't been a heap of dedicated research,  we've more been there as a support function to the main trial network. All the trials are conducted in natural situations on grower paddocks where there might be varying levels of pathogens in the background. We've really been there to support observations of where there might be issues with deep sowing or benefits with deep sowing so largely observational. Well, that's given us the opportunity then to isolate strains of the pathogen which are naturally out there in growers paddock. So we want to work with what's actually happening out in the real world, and that's going to lead to some dedicated controlled environment studies in this second year of the project to really prove these concepts about what might be a barrier and what actually might be a benefit with adopting this.

[00:03:23] Sally Maguire Before we move on to the rest of the investment, what are some of the learnings so far from the first growing season?

[00:03:30] Steve Simpfendorfer Yeah it's sort of funny. We had our initial meeting in Adelaide a month or so ago and it's really hard as a pathologist. You've got to remember you don't get too excited when you find disease because it's usually not good for growers. But what was really exciting is what we sort of predicted around the common root rot did show up in observations from Belinda in South Australia and from Jonathan in WA, where they did isolate more common root rot where they sowed deeper using longer coleoptile genetics. So that was really exciting to go well, it was all based on theory. We thought this would be an issue of a few observations from diagnostics, but to see that happening now in the trials was quite good. The thing that was a bit serendipitous is the other pathogen, which is rhizocotonia solani, which causes bare patch and can cause wavy growth later in the season. Real big problem on lighter soils. It's probably one of the main pathogen issues in Western Australia. It's a big barrier over there to continuous wheat production and what we know about it is the rhizocotonia inoculum was concentrated in about the top five centimetres of the soil is where it really is. And rhizocotonia it starts off as a point infection and it spreads out it hyphe as a network like mushrooms do how you see your mushrooms come in a circle. Rhizocotonia is quite similar to that in that it grows out in that network and that's where you get the bare patch where the plants are basically getting significant rotting at their root system spear tips and they either die or they're really stunted and have this pineapple appearance. And in hindsight, there was some observations. But what seems to be happening is as you adopt long coleoptile and sow deeper, you're actually sowing below that inoculum of rhizooctonia and your primary root systems getting away and growing quickly away from the rhizocotonia and you're not getting that bare patch. So it was really exciting to see, certainly mainly in WA that that happened in a couple of trials. We did observe less rhizocotonia so that's going to be a real focus for Jonathan in WA going forward, he's doing some controlled environment studies on that with varying placement of seeds at depth in that rhizocotonia at the top to show that's what's happening and it's it could be a real benefit to growers inadvertently of adopting deeper sowing. It's more an escape, it's not a control genetics, it's just escaping because we know where the inoculum is concentrating and we're using that as a weakness of the pathogen to actually get around it. So that's quite exciting.

[00:05:36] Sally Maguire At this early stage, is there any sort of grower adoptable information that you can provide?

[00:05:42] Steve Simpfendorfer I think as all scientists. We get a bit cautious. So that's why I think we're following the natural scientific process. We've got observations in the field in the first year now there'll be some dedicated controlled studies done to prove that's what's happening and then probably more solid recommendations. So I wouldn't certainly say let's all go out and sow you know, twice as deep as we used to and we'll get around rhizocotonia in WA, I think that's early days for that, but certainly some encouraging observations which we want to follow through and certainly track down to have that solid recommendation. I think one of the ones, which is pretty obvious, we talked yesterday, we had a meeting and it's quite dry in WA and there is a lot of interest in chasing deeper moisture. The big thing there and Greg Rebetzke the leader of this project, put out there on social media about just be careful of the fungicide seed treatments. So some of those fungicide seed treatments can actually be a barrier to trying to sow deep. They shorten the coleoptile length, particularly those that contain Triazole  in particular it just shortens the coleoptile.  And so, you know, you are doing that because you're forced into the situation with sowing moisture. Just be very aware of the fungicide seed treatment. So that's something that's immediately out there is a message. We knew about this, but it's just good to reinforce it there for growers and certainly as part of this project we will do a bit of controlled environment study because there's a lot of new fungicide seed treatments on the market. So a lot of works quite around. And just to put some information out for growers for following seasons, what to avoid if you are going to try to sow deeper and don't want to shorten that coleoptile length, which will really affect your emergence and establishment.

[00:07:06] Sally Maguire So you flagged it a little bit before, but tell us more about what your research is going to be focussed on going forward.

[00:07:12] Steve Simpfendorfer Certainly in that space, the control environment studies on both common root rot and rhizocotonia that'll happen. And I guess with like last year, we've got that indication that it's causing problems with deeper sowing but we'll then look for workarounds. We don't want to be embarrassed. Growers are going to say, well, I'm not going to deep sow because I'm going to run into common root rot problems. We can certainly test, the risk is very different within paddocks. So that Predicta-B test offered by SARDI you really target so that that. But we will do a bit of work on fungicide seed treatments in that space as well because some of those actually do reduce common root rot. So in the US fenticonazol which is in your Vibrance is a main product used in US for that. So we just need to develop some local information along that. So yeah, that'll be the main sort of things. Giving support again to the field trials across the country as to any diseases show up and based out of Tamworth in this northern region, we're going to do a little bit more work on fusarium crown rot. We did some work last year because the thing that comes along with deeper sowing means you're usually trying to sow earlier in the window for a variety as well and try to make the most of moisture that might be disappearing and going down deep. So what we know from previous work we've done with GRDC funding is certainly that the earlier you sow you tend to escape the heat stress, which really makes fusarium crown rot losses greater. So we're going to do more work on that. But what's quite interesting is there is going to be a new seed treatment that's going to be available to growers, hopefully next year called Victrato out of Syngenta was showing that the efficacy of that again involving GRDC that efficacy is really reliant on soil moisture around the seed zone because the active has got to come off the seed, move into the soil, get taken up by the root system and moved into the base of the plant. And what we've found over a number of years of experimentation is where we get conditions where we get quite dry around the seed zone, which happens a lot in this northern environment where we've got heavy clays and we can grow crops on stored soil moisture and we stay dry in that seed zone we can't get that mechanism for the active to come off the seed and protect the base of the plant from fusarium crown rot. So we're actually going to play this year with deliberately sowing deeper and hopefully in theory we think will happen is if ten centimetres say vs four centimetres, you'll have more buffering of that soil moisture, more reliable soil moisture for that to come off the seed get taken and moved into the base of the plant where it's got to work. So it could be an inadvertent benefit to other strategies for disease with helping with that. So that's another thing we're going to have a look at.

[00:09:28] Sally Maguire So there's such a lot of variables with this investment. What is your hope at the end of it, what you'll be able to provide that growers will be able to take away and then apply?

[00:09:39] Steve Simpfendorfer Yeah, I think that's why it's a national project across varied environments, soil types and all sorts of things. And different regions have different issues with how they use herbicides etc. So the real aim of this is to look at what those interactions with disease are. So rather than putting a new technology out there and letting growers find out what works and doesn't work, actually support them and try to be a bit in front of the game as to what's going to be potential diseases and come up with recommendations to how to stop that limiting their productivity. So by the end of it, hopefully we've got some really clear recommendations backed by solid science which we can take to growers and say, look, if you're going to adopt this in particular situations, as Greg said the other day, you don't have to sow deep all the time. But I think if we can see some benefits, like maybe with this rhizoctonia control if it is helping with more reliable efficacy of some of our fungicide seed treatments with that moisture reaction. That could be another thing, really push us towards trying to adopt long coleoptile wheat as a benefit for the system and and ultimately for productivity and economic growth.

[00:10:34] Sally Maguire So just from your perspective, why are you excited about long coleoptile wheat in general for growers in Australia?

[00:10:42] Steve Simpfendorfer I think yes, certainly there's been a lot of work done on this. That reliability of sowing rainfall is really becoming patchier. So we're quite used to chasing moisture in the northern region of New South Wales, Queensland with chickpeas which are quite reliable coming up from depth. And I think if we just had that technology and have that ability for wheat to do that as well, just gives a lot more flexibility to the farming system to adapt to that change. And we know yield potential is all about sowing time. So if we get that at the start of a sowing window and long coleoptile allows us to get the moisture in and reliably establish a crop, that the yield benefits on their own are huge to growers. But then you put crown rot in the situation, which is a huge problem here. We actually reduce their loss from crown rot by manipulating that heat stress during grain fill, which we always tend to get. There is real flow on benefits. So I think it could be a real benefit to the system of reliably being able to do that. So at present, if you've got stuff that can't reliably come from depth, you get that patchy emergence and you're behind in terms of you just haven't got a plant stem that's going to maximise yield potential. So there's an old saying up where I'm in the north and most agronomists, growers say up here we crop water and what that long coleoptile do is allowed to actually get into that soil moisture at that depth and reliably establish their crops and make the most of that stored water. We have real issues here sometimes where they say the moisture doesn't join up, we've got great moisture at depth, we can grow great crops on it. We just can't get to it reliably. And that's where they might turn to chickpeas, but we can actually bring wheat back into the picture as well. Just adds a lot more flexibility and reliability in the system for growers.

[00:12:20] Sally Maguire That was Steve Simpfendorfer from the New South Wales Department of Primary Industries. And the four-year long coleoptile wheat project, made possible with GRDC investment, is being led by CSIRO, along with research parties including the University of Melbourne, New South Wales, Department of Primary Industries, Queensland Department of Agriculture and Fisheries, SLR Agriculture, Western Australia's Department of Primary Industries and Regional Development, the University of South Australia and EP Ag Research. I'm Sally Maguire. This has been a GRDC podcast. Thanks for listening.