Perfecting the Pea

Chris -   The humble pea is something of a wonder plant, we all like to think - for one thing, it adds nitrogen back into the soil, and that reduces the amount of fertiliser that you need to add to the next crop that you want to grown on the same soil.  But, some scientists think they can make it even better, and Claire Domoney is with us from the John Innes centre, to explain how.  Hello Claire...

Claire -   Hello, Chris.

Chris -   Welcome to the Naked Scientists.  Tell us if you would first of all, why is the pea a good crop?

Claire -   Well, we really want to look at it within the context of increasing the sustainability of agriculture.  We know we have to cut our use of nitrogen fertilisers, so we're looking at the pea as really a model legume crop where we have excellent genetics, and we can use a lot of very powerful techniques - molecular genetics, biochemistry, metabolite profiling - to study seed quality.  We've had lots of discussions with industries involved in growing peas and harvesting peas and so on, breeding peas, and one of the outcomes of these discussions, within what's known as the Pulse Crop Genetic Improvement Network which is funded by Defra, is that quality improvements are really greatly desired.  At the moment, the industry use quite subjective methods for determining quality and so, better methodology for determining quality would really be very welcomed.

Chris -   So let's look at that first of all then.  So, are we defining quality in terms of how consumers see the pea on their plate and how the mushy pea goes down further up north on the coast or are we talking about it in terms of what yields the plant that grows from that pea actually produces?

Claire -   We're talking first and foremost really about quality as perceived by the customer because there are a lot of issues to do with taste, flavour, mouth feel, a lot of customer determined traits, and on this basis, breeders are putting their late generation materials through breeding programs.  They go to taste panels who sit down and score their products on all sorts of characteristics, which is done in a very subjective way as you can imagine.  This is quite time consuming and they end up scoring the different lines on the basis of bitterness and sweetness, and lots of different characteristics like this.  But it really is a very subjective way of determining quality.  So we want to really add some biochemical knowledge to this and do metabolite profiling where we can look at all the range of compounds which are being determined by these taste panels, link those through to the genes that are involved in pathways that make these compounds, and through that, get hold of genetic markers that can be used by breeders.  In that way, they'll be able to use their markers much earlier in breeding programs, and not do as they do at the moment which is reject valuable lines because at early stages, they can't do this type of screening.

Chris -   I see what you mean, so in the same way that people are making better, fatter turkeys that put on more weight in the right places, by knowing that the genes that tend to make those nice traits happen also to produce other visible changes in the birds, so you can, by picking the change in the bird that you can see, get other benefits that you couldn't originally see.  You're doing that, slightly more intelligently and slightly more carefully.  That will obviously produce improvements in quality that will make peas more popular, but what about the other thing we discussed which was the question of improving the soil?  Because peas do have this one full ability to take nitrogen out of the air and shove it into the soil, don't they?

Claire -   Yes, absolutely and of course, we get a value from not just the pea crop itself but also the value to the subsequent crops.  So this can result in a huge saving in nitrogen fertiliser.  And so, this is an incredibly valuable thing to think about, particularly these days with the increasing costs of nitrogen fertiliser as well as the greenhouse gas emission issue associated with nitrogen fertilisers.  So we want to really encourage farmers to choose to grow legume crops more as part of their rotations.  At the moment, we know that they're not taken up as much as they could be, and one of the things we want to do within this project is to do some predictive analysis based on having better systems for guaranteeing quality, and hence a high price return to the farmer.  We want to look at what the impact of this could be on more frequent uptake of legumes as part of rotations.

Chris -   So this is - it sounds like an awful pun, a vegetable analogy  - this is more carrot than stick?  If the pea tastes good, more people will buy it, therefore, more farmers will grow it.  Rather than saying to people, "Just grow this because it's good for the soil".  And in a climate change sort of equation,  it's better for the environment too because you're not putting fertilisers on soils which we know contribute greenhouse gases and also the synthesis of those fertilisers in the first place eventually leads to the release of CO₂.

Claire -   Yes, absolutely.  Of course, there has to be an incentive for the farmer to choose to grow the crops.  The farmers won't grow it simply for public goods, they need an incentive.  There are good quality markets that give a very good price, and if they can access those markets - that's not just the vining pea markets but also the canning markets give a good return to the farmer  - and there are some excellent export markets.  In some years, we don't meet those markets or the potential of those markets in the UK.  So, for example, even for homegrown vining crops in the last, two to three years, we have had to import vast amounts from New Zealand because our stocks were so low.  So there is a lot of potential for increasing production of these.

Chris -   And just to finish off, Claire, where is the project now?  Has it just got going or are you well into it? And what's the timeline?

Claire -   We have just started at the beginning of February.  Really, that was just the administrative start and we are now just starting to set out some plants to grow in plots.  At the John Innes Centre, we have access to John Innes Germplasm Collection which is a collection of over 3,000 lines from around the world.  So we'll be choosing among those for exotic lines which may give us some of the valuable genes that we want to introduce into breeding material.