UGA Seashore Paspalum Breeding Program

Posted on
Text-Only Transcript

Dr. Paul Raymer: And its big claim to fame is it's highly salt-tolerant. It's the most salt-tolerant among all the warm season turfgrasses. We've had a breeding program on Seashore Paspalum since the early 1990s. That program has been very successful in developing a number of varieties, probably 5 or 6 different cultivars. Those cultivars have actually been licensed all over the world - Mexico, Australia, the Middle East, Southeast Asia, China, etc. And have been grown and used primarily by the golf industry. And the reason the golf industry is interested in this grass is because many of the venues that they put golf courses on are salt affected. Coastal venues are a beautiful places to build golf courses. Many of the golf courses are built in tropical paradises but the water quality is very poor - brackish, etc. So this has gained quite a bit of acceptance worldwide. It's a very international grass. Now after 10 years of what we consider success with the grass, we're getting a lot of feedback on it. And one of the big feedbacks is "This grass has got a problem because we can't control bermudagrass in it." Anybody else have a problem with bermudagrass control? It's kind of a hard weed to control. In fact this gentleman right here was our weed scientist when we started working on Seashore Paspalum. He spent several years looking for a selective herbicide that would be able to kill bermudagrass and not damage Seashore Paspalum. Did you find anything B.J.? He didn't find anything. We've had 2 subsequent weed scientists since then that worked on the same issue. They haven't found anything either. So right now, a golf course superintendent’s best option really is to spray it out with Roundup a couple of times at very high rates and cut it out with a sod cutter and then replace it. This problem is big enough that it's threatening the future of this species as a turfgrass. If we don't do something to improve our ability to control bermudagrass in it, people are going to be less likely to adopt it because in 5 years their golf courses are infested withbermudagrass they can't control and they have to consider renovation. So, we had to find a fix. Well one of the big options could be is to be like the row crop guys. Right? We could develop a herbicide resistant system. Anybody know what that is? A few people do. How about Roundup Ready Soybeans, Roundup Ready Cotton, Roundup Ready Corn, Roundup Ready Sugar Beets? Those are the most common examples of herbicide resistant systems. So to build resistance into a crop that's normally susceptible and then thereby allow it to control. Well, Roundup Ready Bent was developed more than 10 years ago by Scott's and it has still not been commercialized and is likely to never be commercialized. It’s never gained approval – a lot of concerns about it. One is out-crossing, etc. In Seashore Paspalum, I don't think it's a good option because the grass is very very international and the cost of registering a g-m product or g-m trait in a turfgrass is outrageous. So you've got to have a really big market and you've got to have enough money to justify it. We don't have that with Seashore Paspalum. Another problem is that every country has its own regulationsand so you have to go through registration in every country you market. So the fact that we market this grass all over the world would be prohibitive to use a g-m related trait. So next idea, a non-g-m trait, right? What could that be? There are examples of non-g-m herbicide resistant systems out there. An example would be Clearfield Wheat which is a natural mutation that confers resistance to imidazoline herbicides in wheat. And it's been deployed successfully and used for many years. We need an IMI kind of wheat system for Seashore Paspalum. First we look for herbicide class of chemistry that would allow us to control bermudagrass or at least manage bermudagrass. The biggest candidate was a group of chemicals called ACCase inhibitors. These are grass herbicides. They're old chemistry; they've been around since the 70s. They've been broadly used to control grasses in a number of broad-leafed crops such as soybeans, sugar beets, canola, etc., around the world. So we've got a class of chemistry that could help us to managed bermudagrass but now we need resistance. Well, if you go back in the literature when we started looking we found that resistance had occurred to some of this class of chemistry in different countries around the world, on different continents – Australia to ryegrass, South Africa to foxtail, Europe to blackgrass. When the weed physiologists started trying to figure out what the mechanism or what the nature of that resistance wasthat had occurred in these grasses these normal weeds could be controlled were no longer being controlled they found a single mutation that was conferring a high level of resistance to these herbicides. And guess what? All over the world, different grasses - same mutation. So now we've got a potential system. We've got a herbicide that controls it - will control bermudagrass or help us to manage bermudagrass. And, we've got a known mutation that is occurring in other species. So all I had to do or all we had to do was devise a very efficient system to find that mutation in the grass thatI wanted in which was Seashore Paspalum. We're able to effectively screen for resistance to this herbicide by lacing the media with the herbicide itself. The result was that we found 63 resistant cell lines; 2 of those cell lines regenerated into resistant plant material. We tested that material with dose response in the greenhouse on mature plants and found a 15-fold increase in herbicide resistance. So now we thought we had made it, this was 2009, we're still 5 years away - that was 5 years ago. Obviously we had a few problems along the way. One of the problems was we had additional mutations from the material. The material wouldn't flower so I couldn't breed with it. So the first test we put out was over here on those 2 tests on the right - that was 2012 and 2013. We tested this initial material with a very high level of sethoxydim resistance against other sethoxydim as well as acouple of other herbicides in this class. And we learned quite a few things. One was the plant material that came out of tissue culture wasn't fit enough to be a commercial variety. Two was with repeated applications in high rates we could manage bermudagrass using this class of chemistry. We had a breakthrough last year. We used a technique call embryo rescue where we crossed the mutant lines that had the high level of male sterility and were able to get about 6 lines back out of this that had the herbicide resistance by back- crossing to a known variety. We got rid of a lot of the extraneous mutations that were inhibiting growth and reducing flowering. 

(c) 2015 University of Georgia College of Agricultural and Environmental Sciences Department of Crop and Soil Sciences - Griffin Campus

Descriptive Text

The video opens to a logo slide for the College of Agricultural and Environmental Sciences then moves to the title slide then continues to a candid photo of Dr. Paul Raymer.

The video changes to Dr. Paul Raymer standing in an outdoor classroom speaking.

The video moves to a slide show of golf courses and sports fields around the world.

The video returns to Dr. Raymer speaking.

The video continues to show a photo of B.J. Johnson, a retired UGA scientist, then returns to Dr. Raymer speaking.

The video changes to a slide of the different 'Roundup Ready' seeds then returns to Dr. Raymer speaking.

The video moves to a slide for Clearfield Production Systems for Wheat then returns to Dr. Raymer speaking.

The video continues to show trail plots of seashore paspalum then returns to Dr. Raymer speaking.

The video changes to show herbicide resistant trial plots of seashore paspalum then returns to Dr. Raymer speaking.

The video moves to a photo of Dr. Raymer working with seashore paspalum that is in gardening containers then returns to Dr. Raymer speaking.

The video continues to show trial plots of seashore paspalum then changes to show herbicide resistant trial plots then returns to Dr. Raymer speaking.

The video changes to a photo of Dr. Paul Raymer then moves to a slide of CAES' college mascot playing golf.

The video ends to a logo slide for the College of Agricultural and Environmental Sciences.

(c) 2014 University of Georgia
College of Agricultural and Environmental Sciences
Griffin Campus
Crop and Soil Sciences Department