Answers to pre-harvest sprouting in pipeline by Denys Slee

Grains in the 'plump' wheat head on the left are sprouting whereas the head third from left is typical of varieties tolerant to weather conditions that lead to pre-harvest sprouting of grain.

A MUCH-AWAITED wheat variety tolerant of conditions that lead to pre-harvest sprouting of grain could be available within five years.

Pre-harvest sprouting periodically results in massive financial losses due to downgraded quality, when rain falls at or very near harvest-ripeness.

According to University of Adelaide Associate Professor Daryl Mares, "In these conditions most of our current commercial varieties will sprout, and sprouting tendency increases the longer the ripe crops are left standing in the field. Some varieties are more susceptible than others - WestoniaPBR logo , for example, is extremely susceptible whereas Janz and Spear are classed as susceptible and moderately tolerant respectively.

"Dormancy protects seeds against germination so that if the grain gets wet; it doesn't germinate. But in most of our commercial wheat varieties this dormancy factor is minimal and provides very little protection."

Professor Mares took seed from the GRDC-supported Winter Cereals Coilection at Tamworth, and tested hundreds of lines for their ability to tolerate pre-harvest sprouting conditions. Eventually he found an old South African-bred wheat with the desired characteristics and, having demonstrated its high level of tolerance under field conditions, spent several years determining how best to handle the transfer of this trait to locally adapted varieties.

Wheat breeders in northern NSW and Queensland began incorporating this dormancy trait into their programs several years ago. More recently breeders in other parts of Australia and overseas have taken up the challenge and, with longer-term support from growers through the GRDC, crosses are now at a reasonably advanced stage.

Chinese connection

"We also now have access to sprouting-tolerant material from China which has good grain size, is tolerant to black point and has yellow spot resistance. And with CSIRO Plant Industry researchers we are looking at the 'architecture' of wheat so that, perhaps, varieties that don't capture so much water in their heads can be produced - they might be awnless or waxy, for example."

Program 1 Contact: Assoc. Professor Daryl Mares 08 8303 4455

Region North