New maize list format and additions

New maize list format and additions

Thursday, September 15, 2011

Two key changes have been made to the 2012 NIAB Descriptive List for forage maize, which will help farmers choose the best maize varieties for their situation.

BSPB and NIAB say including data on cell wall digestibility - an increasingly important factor for farmers feeding high levels of maize silage in the diet - will be useful.

NIAB's Don Pendergrast explains growers will be familiar with the D value of their maize silage - this is based on an analysis of the whole plant. "The cell wall digestibility - CWD - differs in being based on the analysis of just the leaf and stem, which account for 45-55% of the weight of the plant," he says. "Values of cell wall digestibility typically range from 50-60%, so any varieties with CWD in the late 50s can be considered more digestible. These will be broken down in the rumen more quickly by the animal, increasing potential dry matter intakes."

Another departure for the List is the removal of the maturity class system which, Don says, now hinder, rather than help, growers to maximise their crop yields.

"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 4-7 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 per week.

"Plant breeding has made great advances in the last decade and modern varieties are drying down at a rate of 3-5% per week - so in fact there's only a difference in reaching target DM for harvesting of 2 days.

"Also, while the genetics of a variety remain the same over time, the maturity class bands move. For example, the variety Lincoln was a maturity class 7 when it first appeared on the List over 10 years ago, but today it would be a maturity class 5 or 6."

Robert Jackson, BSPB's variety trials coordinator says BSPB's maize crop group made the decision to remove the maturity class system from the NIAB List because it was no longer working to the benefit of growers. "It was in fact restricting their variety selection to a certain maturity class, when they could have widened their options and chosen from a bigger range of material, perhaps choosing slightly later material and getting 5-6% more yield, for the sake of harvesting just 2 days later."

Limagrain UK has announced that the list now includes three new high yielding LG varieties from its UK breeding programme.  The 2012 NIAB Descriptive List for forage maize includes: Garland, Acumen and Vivacity, says the company.

The new NIAB list format means growers only have dry matter percentage as their guide to compare the earliness of different varieties. So to give growers an indication of the earliness of the new LG varieties, the following information includes a guide to maturity class, according to Limagrain's Tim Richmond.

"Of the three new LG varieties, Acumen and Garland are very early maturing - both would be in maturity class 11 on the old system. Acumen is one of the earliest maturing varieties on the new NIAB List. It has demonstrated very high dry matter yield and starch content in both NIAB and Limagrain trials, and ultimately delivers an exceptional starch yield. Acumen is ideal for growers in marginal areas wanting to maximise yields of dry matter and starch."

On the NIAB Less Favourable List, Acumen yields 18.2t/ha of dry matter (102% of controls), and has a starch yield of 6.37t/ha - 108% of the controls. It has excellent early vigour ensuring good plant development in the important spring growth period.

"Garland is another early maturing, high starch provider. It also boasts improved digestibility thanks to its high cell wall digestibility. It has a high stay green score, which means the plant photosynthesises and accumulates energy right up to the last day before harvest. So it gives an excellent yield of energy-rich, high ME silage," says Tim.

On the NIAB Less Favourable List, Garland achieves a DM yield of 18.0t/ha and a starch yield of 6.47t/ha - the highest available at 110% of controls, and an ME of 11.5 MJ/kg DM.

"New variety Vivacity is also early maturing, with an equivalent maturity class of 9 on the old system. Vivacity is ideal for growers in mainstream areas wanting to maximise energy from starch in their ration. On the new List, Vivacity has a dry matter yield of 17.8t/ha, starch yield of 6.17t/ha and starch content of 34.6%. It also has a very high metabolisable energy yield 201,151 MJ/Ha."


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