A new maize crop ripeness index based on a nationwide field trial programme is being developed to give a better indication of maturity than traditional data.
The move follows concern about the way NIAB trials presents data on regional stability of maize varieties, particularly in marginal areas.
Many people are concerned about the way varietal suitability is presented by NIAB, says Grainseed’s Neil Groom.
“In the last three years in particular, several varieties promising early maturity haven’t actually delivered in the field or ration as they haven’t achieved their dry matter percentages through grain maturity.”
In effect, many varieties appear to have good NIAB maturity ratings, but this is gained through rapid plant dry down rather than grain maturity.
“Maturity groups have to be treated as a guide to selecting varieties for specific growing environments – they are not a precise tool,” he says.
The new cob ripeness concept is based on the idea maturity is not simply about dry matter, but about the plant’s ability to finish the process of laying down as much starch energy as possible.
“Similarly, starch content is not a true indicator of maturity either as that factors in total plant yield too.”
The new index will take into account many different facets of the variety’s overall performance under a range of conditions to give a true indication of the plant’s ability to “finish”.
“The new index will be of particular benefit to growers in marginal areas,” Mr Groom stresses.