Farmers choosing maize forage varieties will no longer be able to select based on the traditional maturity selection system, following the removal of maturity classes from the NIAB Descriptive List.
The 2012 list, launched at this year's Dairy Event and Livestock Show, no longer includes the maturity class system which was deemed as more of a hindrance rather than an aid to farmers looking to maximise their crops.
Instead, farmers are being encouraged to select maize forage varieties using a dry matter selector.
NIAB's forage and livestock manager Don Pendergrast said: "When the maturity class system was first set up, the difference in dry matters at harvest between one maturity class and the next was equivalent to four to seven days in target harvest date.
"This was at a time when varieties would be drying down in September at a rate of 1-2% DM a week. However, plant breeding has made great advances in the last decade and modern varieties are drying down at a rate of 3-5% a week – so in fact there's only a difference in reaching target DM for harvesting of two days."
Responding to the changes to the descriptive list, Richard Camplin from Limagrain said he feared farmers would be confused by the changes at first, but said it had the potential to widen the options available to growers.
And for those still wishing to select based on maturity, he said the company had produced its own maturity selection system covering three bands - late, early and very early - using data from the NIAB list.
Neil Groom from Grainseed said although he didn't agree with the removal of the maturity classes from the descriptive list, it would encourage farmers to reassess how they select and mark a move towards selecting based upon what has worked in their region, rather than maturity classes.
John Morgan from the Maize Growers Association added: "We understand why NIAB have done it, but still plan to produce our list with maturity classes because we think farmers are going to struggle to distinguish between different varieties without it."
Syngenta's Nigel Padbury said he fully supported the removal of the maturity classes because they were restricting the choice for farmers and making it more difficult to compare varieties.
"The dry matter score now runs from around 30-40%, and if you want to know the maturity class scoring, I'd recommend just scoring out the first digit," he added.
In addition to the removal of the maturity classes, the 2012 NIAB Descriptive List now includes data on cell wall digestibility.
Mr Pendergrast said: "With maize silage increasingly being fed at high levels in dairy cow rations, the digestibility of the plant's cell wall starts to play more of a role in the energy value of the silage."
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