Genetic tweaks helping wheat to use nitrogen more efficiently have been one of the keys to raising yield and quality.

Prof Malcolm Hawkesford, head of the Designing Future Wheat Institute Strategic Programme at Rothamsted Research, says: Since 2004 weve conducted field trials of more than 60 varieties to examine yield, quality and nitrogen use efficiency (NUE) at various nitrogen rates.

This unique dataset has given us insights into genetic and climatic trends including annual variability.

For example, weve shown how recent higher yielding varieties can better use more N and hence have a higher NUE.

The Genetic Improvement Networks, or ‘GINs, were set up to bridge a gap between researchers and plant breeders, once described as a ‘valley of death, by creating pre-breeding material having new profitable and sustainable characters.

WGIN4, the latest in a series of projects on wheat starting in 2003, aims to improve the resilience of the crop through genetics and targeted trait analysis, explains Rothamsteds lead scientist, Prof Kim Hammond-Kosack.

A third of our effort goes on developing new genetic resources, she says.

Germplasm

This has involved purifying the Watkins wheat collection, never previously used in commercial wheat breeding, precise sexual crossing, and seed multiplication through generations in glasshouses and then small field plots.

The new wheat germplasm arising is made available directly from the researchers involved and via the Germplasm Resources Unit at the John Innes Centre.

The material, free of intellectual property, may be used by all breeders.

Over the years, various methods have been used to place molecular markers on each of wheats 21 chromosomes in the new germplasm.

This gives each genetic stock a unique fingerprint, says Prof Hammond-Kosack.

These markers are also used for fine mapping the location of genes controlling each desired trait on the different chromosomes.

The rest of the research effort goes on analysing various traits under four overarching challenges:

• Resilience: Resistance to slugs, BYDV*, septoria, yellow rust and take-all.

• Sustainability: Yield stability, spring drought, lodging* and stem anchorage*.

• Quality and yield: Grain protein and specific weight*, nitrogen use efficiency and nutrient partitioning as affected by N input and disease*.

• Efficiency: Enhancing nitrogen resource efficiency.

The analysis of various desirable crop traits is done by specialised teams or individuals using established and/or newly developed quantitative screening methods to detect variation in each desired trait, says Prof Hammond-Kosack.

Sometimes the screening is by eye, but often it involves handheld devices, specially designed larger equipment, or analysing images collected by high specification drones.

It had been hoped that WGIN4 would become more closely involved with the AHDB monitor and strategic farms.

But farmers dont have equipment to do small plot trials and WGIN researchers dont have enough seed of promising lines to undertake field-scale trials, says Prof Hammond-Kosack.

So, the ‘valley of death remains but has shifted location.

Results

The Rothamsted stand at Cereals, JIC annual Plant Breeder days and the annual stakeholder meeting are great ways to see how we evaluate the new traits, see the latest results, and meet the WGIN scientists.

• Aphids and BYDV A new bioassay testing wheat germplasm to distinguish between resistance to aphid feeding and resistance to BYDV is being piloted as a service to commercial wheat breeders.

• Resistance to multiple pathogens and insect pests A promising new pre-breeding collection, based on a diploid wheat rarely used for modern wheat improvement, is to be evaluated by breeders.

• Root anchorage Varieties and individuals from populations showing strong root anchorage have been identified.

They are likely to be more resistant to lodging and their stronger, deeper root system may contribute to drought tolerance.

• Slug damage Seed of a line from the Watkins collection showing some resistance to slug damage is being distributed to selected farms for testing.

Although not providing funding, AHDB is involved throughout the project as a member of the WGIN management group, attending three meetings a year, with representatives from all UK-based breeding companies, Defra, NIAB and Bristol University.

• Spring drought Chromosomal regions from a drought-tolerant wheat are being introduced to a UK variety for field testing.

• Yellow rust resistance Despite the UK/European population changing several times, one Watkins line remains fully resistant.

Subsequent analyses show this highly desirable trait is controlled by one or two dominant genetic loci and could be introduced into commercial wheats

Defra should be commended for thinking ‘long term with all the GIN programmes, says Nicholas Bird, winter wheat research lead at KWS UK.

He says: Breeding an improved wheat variety takes at least 10 years from the initial cross to farmers fields.

Introducing novel genetic regions can double that.

This is where long-standing investment in academic research with industrial involvement can really start to make a difference.

The WGIN programme is a fine example of this; the industry welcomes the current research findings and is deploying them in breeding programmes.

Given this years difficult growing conditions, which mirror 2020, the research into drought tolerance and rooting is timely; it should help future varieties cope with lower rainfall once the relevant genetic regions are deployed.

Managing pests and diseases with fewer control options, either through legislation or reduced biological activity, is another area where WGIN can help, says Mr Bird.

Research into novel germplasm collections showing promise against resistance in septoria, yellow rust, slugs and aphids should allow faster and more effective deployment into mainstream breeding activities.

The work on nitrogen response has been positive for breeders, allowing them to show how they have been selecting varieties better placed to make use of that nutrient, he adds.

Using predictive breeding strategies means further advances should be possible.