Tackling black point and early sprouting

Researchers in three States are using the latest biotechnology to confront black point and early sprouting which cause major annual losses to wheat growers through direct crop losses and downgrading. And it now appears the two conditions could be related.

Black point is a dark discolouration at the germ end of otherwise healthy wheat or barley grains, once thought to be the result of a fungal infection.

Peter Williamson of the Leslie Research Centre in Queensland says it is more likely to be caused by a pigment, resulting from stress-caused disruption of the ripening process. While the mechanism is not fully understood, yield, humidity and temperature are probably involved.

Pre-harvest sprouting occurs when there is high rainfall in the time between grain maturity and harvest. A research team at the University of Sydney has found that grain showing black point is much more likely to undergo pre-harvest sprouting if exposed to further rain, which suggests a link between the two problems, possibly related to black point causing the grain to lose its dormancy.

Researchers have developed a doubled haploid population between two wheat varieties: Cascades, which has good resistance to black point, but is susceptible to sprouting; and AUS1408, which is susceptible to black point, but resistant to sprouting. They are using this population to look at the relationship and to screen for molecular or biochemical markers that would allow rapid screening for the traits in other varieties.

Researchers at the Victorian Institute of Dryland Agriculture (VIDA) are tackling pre-harvest sprouting from a different angle, using a genetically different source of sprouting resistance. VIDA wheat breeder Russell Eastwood says they have had very promising results using the wild wheat species Triticum tauschii, which has good sprouting resistance, for interspecific crossing into modern wheat varieties.

Program 1.2.3 Contact: Dr Peter Williamson 07 4639 8826 Dr Russell Eastwood 03 5362 2111

Region North