The desire to cut our consumption of food additives such as sugar and colouring agents has been one of the driving forces for the development of new varieties of pea for food.
Dr Claire Domoney is Head of Metabolic Biology at the John Innes Centre, the lead partner of the Pulse Crop Genetic Improvement Network (PCGIN), she says that PCGIN has been successful in identifying new types of pea that offer higher seed sugar and enhanced pigment retention, attributes that are very attractive to the canning and export food industries.
Here she explains how improved genetic knowledge of peas and faba beans is an important output from recent work by PCGIN and its related projects.
This has resulted in the knowledge of how traits with particular economic importance such as good colour and flavour might be stabilised.
Important traits that give growers a good return for their crops.
How can traits have economic value?
The requirements of the end-use (vegetable vining and canning, fresh product and feed) industries for peas and beans are really very different. Knowledge of the genetic traits that control quality, and care when harvesting can result in a premium product for the food industry in particular.
At least two types of pea seeds can be canned: immature and mature. Immature seeds can be from the same types of lines used for vining (for frozen markets) but for canning the seeds will be harvested at later stages of development.
This difference between these two markets is largely due to the industrial processes involved; in canning, for example, cans are rotated during and after heat treatment (cooking) and so require a robust seed that will not become damaged.
For mature seeds, the canned types are often marrowfat (large-seeded) varieties; high quality requires good colour retention, lack of starchiness in the canned liquid, lack of seed coat splitting and good flavour.
How can knowledge of traits impact commercial use of colourings?
There is pressure on the food industry to reduce the amount of additives used in production. Colour is valuable in making canned, dried and snack products look appealing to the consumer and so artificial colouring is often used. Mutations that lead to higher seed sugars and enhanced pigment retention are thus of great interest.
PCGIN is tasked with legume crop improvement in the UK , within its QDiPS project sources of new genes that control pea seed composition and colour stability have been identified. This is exciting as new genetic markers for these traits will be used to support the rapid selection of desirable lines from breeding programmes.
Also within QDiPS, improved genetic knowledge will allow the selection of genes that affect the sucrose content of seeds. Some of the new lines have been made available for testing under commercial conditions in, for example, fresh pea picking market trials.
Seed quality targets in faba beans are also being studied and new mapping populations, developed with input from the breeders, are now available for trials.
Peas are good in rotation as they add nitrogen. Is there any evidence that growing peas leads to a reduction in the need for nitrogen fertilizer?
Absolutely, and farmers are to be rewarded for growing legumes under the Basic Payment Scheme as they fix nitrogen, reducing the need for fertiliser.
Although the actual figures quoted for fixed nitrogen vary a lot and are often misquoted, the saving in nitrogen fertiliser costs, plus the benefit to the yield of the following crop, should rightfully be attributed to the legume/pulse crop. It was estimated that the value of growing legumes was about £200 per ha some time ago, but of course this will vary according to current fertiliser costs plus crop market value.
How are researchers responding to the withdrawal of fungicides?
Of course the biggest challenge facing pea farmers is weather and its prediction. The last few years have brought huge contrasts, drought, deluges, cold and heat, and breeding crops that are more resilient to all of these is a huge task.
Ultimately what most pulse crops really need is cool conditions followed by heat, delivered at the right times. Prevalence of disease is linked to weather conditions, and the more limited range of fungicides available now means that diseases overall are becoming more of a problem to manage.
The discovery of novel sources of disease resistance and introgression into new varieties will help and the results from the PCGIN pea trials in 2013 were very promising.
John Innes has a vast germplasm collection; how does access to these exotic lines add value to your work?
It is probably fair to say that, without diversity, breeding is going nowhere.
The John Innes Germplasm Collection has a collection of over 3,000 pea lines from around the world and all our sources of novel variation for plant and seed traits as well as sources of disease resistance stem from this.
Our exploration of the more exotic lines and landraces – collected from various regions of the world including some extreme habitats – provides a huge reservoir of superior alleles of genes controlling numerous traits.
This resource, together with recent developments in high-throughput screening and sequencing, is allowing us to discover and categorise variation much more quickly.
In addition, we are working closely with pulse crop geneticists in Canada, whose research is very closely aligned to the needs of growers and the related food industry through Pulse Canada.
In summary, new varieties with improved standing and some impressive yield results are already available with further developments in the pipeline.
Have you found growers receptive to new varieties?
Yes, to convince growers in the UK to trial new varieties, a good approach is to highlight the higher disease resistance that is evident in new varieties. This translates to fewer inputs and a better balance sheet for the crop, which is very attractive to farmers.
Find out more about PCGIN at www.pcgin.org