Science advances providing a boost for plant breeding
RAPID developments in new areas of science such as genomics and bioinformatics are helping to deliver advances in plant breeding that will benefit farmers across the globe.
In the UK, scientists are applying these new tools across a range of field crop groups, including wheat, pulses and vegetables.
At the Norwich-based John Innes Centre, a longstanding tradition of expertise in pulse crop genetics is being put to use across three major projects: PCGIN (Pulse Crop Genetic Improvement Network) and arising from PCGIN, QDiPS (Quality Determinants in Pea Seeds) and ProtYield (Protein content vs yield in legumes – releasing the constraint). Much of the field trials work associated with these projects is being carried out by the Processors and Growers Research Organisation (PGRO).
PCGIN was set up, with primary funding from Defra, as a genetic improvement network and to link researchers and industry stakeholders.
Dr Claire Domoney, head of JIC’s Department of Metabolic Biology, explains how farmers will benefit from the project.
She says: “Within PCGIN we are focused on some of the seed quality and plant quality traits which are important and significant in terms of the return the farmers get for their crops, but that also impact on sustainable agriculture in a positive way.”
One important quality trait is that of controlling seed colour in field peas. Loss of seed colour in marrowfats, for example, is an aspect of pea quality that could be addressed by plant breeding.
“This is economically important, it impacts hugely on the return to the farmer, so there is a lot of interest in knowing how we could stabilise seed colour,” says Dr Domoney.
Key to obtaining any improvement in seed colour is the ability to correlate the trait with the gene(s) controlling it.
“If we can pinpoint genes which control quality traits, we can provide this information to breeders; we can provide them with the information they need to make a positive selection for a trait,” says Dr Domoney.
Gene mapping of pea lines, including wild and/or exotic types, landraces and commercial varieties, is allowing scientists to hone in on the genes responsible for seed colour far more quickly than has been possible in the past.
“Identifying the association between genes and traits is something which traditional breeding, involving crossing and back- crossing, would take a very long time to do, so we have devised ways by which we can test genes much more quickly to ascertain their property effects in seeds.”
Another area of research within PCGIN is yield trait determination. While weather and other environmental influences have a huge effect on yield, scientists are also now getting a handle on the genetic factors which control yield. At JIC gene mapping is being used to analyse the yield variability in the progeny from crosses of select high yielding pea parent lines and a positive correlation between a specific set of genes and high yield has been identified.
“This is the kind of data which gets us really excited – when we see a positive correlation between yield and markers and we can identify a positive effect on yield from a set of genes that belong to one of the parents. This for the first time is giving us a handle on the genes which could be used in breeding programmes to positively select for yield,” says Dr Domoney.
In further pulse crop work, JIC researchers are seeking to obtain a better understanding of quality in vegetable peas in order to improve market opportunities.
The QDiPS project – a LINK project – is focusing on quality determinants and defining the optimum harvest time for vining peas, which is currently determined using somewhat dated ‘tenderometer’ technology. “We are looking to put more biochemical measurements behind that decision. We have lots of different genes which we know are involved in determining optimal quality and we are assessing those with the industry and biochemically in the lab,” says Dr Domoney.
A third project, ProtYield, is exploring the relationship between yield and protein content in peas.
“There is a big interest in increasing the amount of home-grown protein we produce in the UK and Europe but there is also of course a drive to increase yield and the question is ‘can we do both?’”
The accepted position across a range of crops is for there to be a negative correlation between yield and protein content: higher yield equals lower protein and vice versa.
“However, it is also clear there is a big spread in protein content, so that is really what we want to look at in terms of what is controlling that spread. Is it related to yield? And is it related to quality?
“We can target particular proteins which we can say are a bit of a waste of space in the seed – they are not well digested or they interfere with nutritional quality. So if we remove these from the seed can we at the same time increase yield and increase quality?”
These recent advances in the rate at which genetic material can be screened, in combination with developments in bioinformatics - ways of storing, retrieving, organising and analysing biological data - mean scientists and plant breeders are now also able to screen much more widely for genes and traits of interest. JIC researchers have, for example, recently identified four variants of a gene controlling the stability of cotyledon colour in peas but only one of these is currently present in commercial varieties, with the others located in wild exotic types and mutations.
“This really highlights the narrow genetic base of commercial material and we can widen this considerably by providing information on these alternative genes,” says Dr Domoney.
Defra-funded Genetic Improvement Networks
PCGIN – Pulse Crop Genetic Improvement Network (www.pcgin.org)
WGIN – Wheat Genetic Information Network (www.wgin.org.uk)
OREGIN – Oilseed rape Genetic Improvement Network (www.oregin.info/index.php)
VeGIN – Vegetable Genetic Improvement Network (www2.warwick.ac.uk/fac/sci/lifesci/research/vegin/)