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Arable

Trait focus to address OSR yield instability Conventionally bred Amalie was launched by Limagrain as its first TuYV-resistant variety, while the company’s first hybrid with resistance to TuYV, Architect, is a Candidate on the latest Recommended List.

An oilseed rape breeding programme focused on delivering varietal traits specifically relevant to UK growing conditions could help close the gap between the genetic potential of crops and their on-farm yields in this country. Dominic Kilburn writes. According to plant breeder Limagrain UK, breeding varieties to suit the environmental conditions where they are to be grown is key if yield stability is to be maintained and if growers are to overcome difficulties with the crop. Speaking at the company’s Rothwell base in North Lincolnshire, Limagrain’s senior oilseed rape breeder (Maritime), Dr Vasilis Gegas (right), said that on-farm yield was lower than the crop’s potential because of a number of influences including pests, disease, environmental conditions, agricultural practices and crop management – all parameters that supress yield. “These all play a part in yield instability which, in turn, affects profitability,” commented Dr Gegas, but he suggested that this could be solved through the mitigation of risk by breeding for key traits such as resistance to light leaf spot, turnip yellows virus (TuYV) and pod shatter, as well as through crop resilience, height and maturity. “The most important thing is to smooth out the fluctuations in yield each year and this is where precision breeding comes in,” added Dr Gegas. With one of its three main OSR breeding programmes based in the UK, Limagrain has invested heavily

in a programme where the discovery and identification of specific and suitable traits for UK conditions is accelerating the speed at which new varieties are coming to market. “We first discover a series of traits before moving on to the precision breeding stage where we cross plants with those that have the required traits – so the baseline is already there in the selection process. If those traits are not there in following trials then we can discard the no-hopers and concentrate on the top material. “We don’t have to grow a lot of plants and hope to stumble on something good, and this has resulted in a much quicker plant breeding selection process compared with more traditional breeding techniques,” he explained. “We know within a very short time if a cross is going to be suitable because of its genetic characteristics,” he said, pointing out that breeding in nurseries under UK conditions has contributed towards building up yield and yield stability in the programme.

Characteristics Continual assessment of the market to identify variety requirements as early as possible is on-going and a vital ingredient in the company’s breeding programme, Dr Gegas continued, highlighting the examples

of pod shatter (POSH), turnip yellow virus (TuYV) and club root resistance as key characteristics introduced in LG hybrids in recent years through dedicated breeding programmes. According to Dr Gegas, POSH resistance can help reduce seed loss caused by rain or hailstorms near harvest. As crops hit maturity they are more vulnerable to rain and hail, which induces seed loss, but it’s also a problem the moment the combine header hits the stems – with most growers looking at the back of the combine for seed loss, he suggested. “With POSH resistant varieties, although not all have the same level of resistance, you see almost nothing in terms of volunteers,” he said. “In addition, the harvest period can be extended by up to 14 days which provides reassurance during a stop-start harvest,” he added.

TuYV resistance In 2014, conventionally bred Amalie was launched by Limagrain as its first TuYV-resistant variety, while the company’s first hybrid with resistance to TuYV, Architect, is a Candidate on the latest Recommended List. The virus is now more widespread in the UK than originally thought, with a wide range of host crops and weeds, and large increases in the aphid vector Myzus persicae. “With no effective seed treatment or foliar spray, resistance to TuYV reduces risk of early infection,

resulting in as much as a 30 per cent reduction in seed yield and reduced oil content. Resistance helps varieties reach their true yield potential, increasing yield stability and, in high pressure situations, can give varieties a 10 per cent yield benefit compared with non-resistant,” he commented. “Architect is the first hybrid with TuYV resistance and has significantly higher yield potential than Amalie. It also possesses POSH resistance, is vigorous and winter hardy,” said Dr Gegas.

Club root With club root also an increasing problem in the UK, and now not just confined to its more traditional northern stronghold, Limagrain has a significant R&D and breeding programme in the UK dedicated to building resistance to the disease and overcoming yield penalties often associated with club root-resistant varieties. Hybrid variety Archimedes, said Dr Gegas, has finished NL trials and carries resistant traits to POSH, RML 7 (phoma) and light leaf spot, in addition to club root. The variety is stiff stemmed, has good early vigour and early maturity, which is particularly suitable for Scotland, he pointed out. “This variety is now one of few options for northern-based growers in club root-affected regions and its balance of traits make it a good variety,” he added. Limagrain’s HOLL-dedicated breeding programme is also starting to deliver a pipeline of varieties, while the breeder’s first Clearfield variety, Conrad, is currently in trials, he added. ■

Recognise the benefits of traits Limagrain’s arable marketing director, Les Daubney (right) said that at a time of increasing challenges in growing oilseed rape, it was important that growers look beyond the top-end yield offered by varieties on the Recommended List and to recognise some of the traits that are available. Many growers go into default mode and opt for best yield when making their varietal selection but gross output is not always the best selection criteria, he pointed out. He said that the Least Significant Difference (LSD) average figures on the RL show that gross output is one of the least reliable benchmarks of varietal performance, while characteristics and traits such as light leaf spot resistance and oil content were more guaranteed with lower LSDs by comparison. “At a time of significant risk in growing and managing OSR, it’s about looking after what you have and not always chasing yield. Choose varieties by paying closer attention to the traits, and this will reduce growing risk and give more consistent crop results,” he concluded.

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