Seed treatment not only route to maximum yield
By Xxxxxx Xxxxxx
SEED dressing MON65500 cuts take-all and increases yield in second wheats. But first year HGCA trials suggest other techniques are essential to reach full yield potential.
"The trials have shown us that seed treatment does decrease take-all incidence and severity," says project leader Stuart Knight of the Arable Research Centres eastern region. "And that is reflected in yield increases, especially in September-drilled plots and high take-all sites."
But traditional counter-measures, such as later drilling and more and earlier nitrogen, are needed to reach maximum yield. "All the factors you can use to control take-all are additive," he stresses.
Averaged across sites at Kettering, Cirencester, Wye and Great Carlton in Lincs, Sep 10-drilled plots yielded an extra 0.29t/ha (0.12t/acre), or 4%, when MON65500 was added to the standard Beret Gold (fludioxonil) seed treatment. Drilling a month later the average benefit was only 0.09t/ha (0.04t/acre).
But only the brickearth soil at Wye, Kent, was particularly take-all prone. There the seed-treatment proved more beneficial, increasing yield by 0.45t/ha (0.18t/acre) and 0.52t/ha (0.21t/ acre) respectively on early and late drilled plots, notes Mr Knight.
Seed-rates of 200-400 seeds/sq m made no significant difference to the response. But in a different series of trials, across the same four sites, increasing nitrogen and applying more early did help overcome the take-all effect.
Again, that was most marked at Wye.
Beret Gold treated seed, sown on Sep 10, given 160kg/ha (128 units/acre) of N split 20% early and 80% as the main dressing yielded just 6.97t/ha (2.8t/acre). Drilling on Oct 10, adding MON65500, and splitting a 240kg/ha (192 unit/acre) N dose 40%:60% saw yield leap to 9.51t/ha (3.85t/acre).
"The seed treatment alone may not be enough to maintain maximum yields, but add in the rest and it is quite a big increase – over 1t/acre."
Response to MON65500 is lower than previously reported (Arable Mar 12).
However, comparisons are unjustified and could be misleading, especially as the latest trial sites were not chosen for their take-all incidence, warns Mr Knight. *