SY HARNAS powers away
Oilseed rape crops have started to respond to longer day length and warmer temperatures, with the hybrid vigour of SY Harnas powering away with new growth. The differences in development have been clearly evident on the northern and Scottish Syngenta Innovation Centres this week (21 March), reports the company’s Technical Manager, Dave King.
“The growth habit of SY Harnas over the winter has been compact, with most the hybrid vigour channelled into root development.”
“Now the SY Harnas is powering away,” says Dave King. “It’s using that energy to create a plant structure and green leaf canopy.”
He believes that will help it to take most advantage of the longer day length in Scotland and the north of England. Over the past three years, SY Harnas has consistently proven the highest yielding oilseed rape variety for Scotland and the north.
This season’s Syngenta Innovation Centre trials - which are designed to mirror real farm situations and demonstrate the practical application of pioneering new technologies - have shown 40% more growth on the SY Harnas plots sown at 50 seeds per m2 (below, top) compared to conventional ‘00’ variety, DK Cabernet Y H(below, bottom).
At lower plant populations, from sowings of just 20 seeds per m2, the differences were even more visual.
“Furthermore, the SY Harnas leaves are now significantly greener and healthier, with far less purpling or die back,” reports Dave.
“They are far better placed to photosynthesise to drive yield and oil content.” Trials in Lincolnshire have also shown real promise for boosting green leaf growth with a manganese seed treatment, he adds.
Syngenta Area Manager for Scotland, Iain Lindsay, highlights that many of the oilseed crops that had gone through the winter with very forward growth in the mild conditions, have more recently been hit by the frosty nights and cold easterly winds. The effects have been evident on the company’s Innovation Centre at Berwick, he reports.
“The forward crops have visibly gone backwards and lost leaf area, which has proven a waste of nitrogen and growth potential,” he warns. The loss of each unit of Green Area Index from leaf die back equates to 50 kg of N per hectare.
He believes SY Harnas is particularly well suited to typical growing conditions for northern England and Scotland, where the compact winter growth habit avoids the worst excesses of winter die back, and the plant canopy structure then powers the green leaf to drive yields (below).
“The whole growing cycle for oilseed rape is about building the canopy to convert more sunlight energy into oil in the final few weeks before harvest,” advises Iain.
“Further north we have the greatest potential to harness the longer day length into higher yields,” says Iain Lindsay.
Light Leaf Spot resistance
Adas plant pathologist, Faye Ritchie, reports this season has been the worst for Light Leaf Spot she has ever experienced. The disease could be found on crops as early as November, and has continued to cycle and reinfect plants right through the winter. She believes varietal resistance can play a role in minimising the speed of LLS development and the severity of reinfection between fungicide sprays.
Faye calculates that, in practical terms for growers, there is significantly greater difference between varieties with an AHDB list disease resistance of 4 or 5, compared to a rating of 6 or 7 – which would effectively be managed the same in the field, she adds.
The differences have certainly been apparent in the Syngenta Innovation Centre trials, according to Dave King. “Using a two-spray fungicide strategy with strong Light Leaf Spot activity, the variety Charger, with a resistance score of 4, still had clearly evident symptoms of infection in mid-March (below); the SY Harnas and SY Florida, both with LLS rating of 6, had little or no signs of infection.
“Our trials show that, in the field, the combination of continued good varietal resistance and a robust fungicide strategy can successfully mitigate the impact of Light Leaf Spot, even in high pressure situations,” he adds.