For the first time anywhere in the world the soybean crop's extreme sensitivity to day length has been overcome.
CSIRO Division of Tropical Agriculture plant breeder Andrew James has successfully incorporated high yield from lodging-resistant soybeans from the US mid-west and a'long-juvenile' trait, developed in Brazil, into cultivars for sub-tropical conditions.
Soybean growers in Queensland and northern NSW will have a new variety available late next year which has substantially outyielded the currently popular variety Manark in trials in most environments — up to 40 per cent where the mean yield was greater than 4 t/ha.
Further work — supported by growers through the GRDC — should lead to varieties with similar yield breakthroughs for the demanding dryland environment of Central Queensland.
Extending the planting window
The 'long-juvenile' trait is basically an extension of the growing period of soybean losing the crop's traditional sensitivity to day length. "This will open up a much wider planting window," said Mr James.
"The planting window could be as much as five months, because we found little evidence of day length effects on time to flowering over a range of sowings from mid-August to mid-February," Mr James said. "This would allow a crop to be planted whenever planting rains fall in the warm months of the year, and we suspect the new lines will likewise exhibit broader adaptation to latitude than existing varieties."
Mr James said the yield advantage of the new lines comes from their ability to produce a lot of beans on each plant in favourable environments, up to 50 per cent of total plant weight at maturity, where more traditional varieties might have only 30 per cent of plant weight as beans.
Subprogram 2.5.1 Contact: Mr Andrew James 07 3377 0278