Wheat quality surprise: it's up to you and the weather, variety stays consistent by Alec Nicol
GroundCover™ Issue: 43
DO NATURE and management have more impact on wheat quality than variety, when crops are grown in different environments? That's what four years of research at the Wagga Wagga Agricultural Institute suggests.
In an attempt to determine just how flexible current varieties are, 15 were sown at two trial sites in each of six regions across the country. Varieties were grown outside their 'home' environment, tested for a range of quality parameters, and then compared across sites.
The results turned conventional wisdom on its head. No matter where they were grown or what quality characteristic they were tested for, the top three or four varieties and the bottom three or four were consistent right across the sites.
Helen Allen, cereal chemist at the Institute, said the trial was testing how flexible our varieties are, with the subtext of whether it's possible to 'drought-proof' supplies of premium grades.
"Our results show that you can take specialist varieties, like the noodle wheats, and grow them successfully outside their traditional area" — the main variables affecting outcome being weather and management.
"The trial ran from 1998 to 2001 and during that time we experienced all the vagaries that happen each year in the wheat crop. A frost in October 1998 knocked out three sites. 1999 proved to be so poor that only four of the sites yielded crops worth testing.
"The following year two of the northern NSW sites were flooded out and one of the Queensland sites was subjected to extreme water stress. In any one year we saw high screenings, low test weights, black point and small grain size at one or another sites, the usual problems that growers confront. "
North just has to be different
While 'good' varieties tended to be good and 'poor' varieties poor everywhere, there were some anomalies in the trial that Mrs Allen says she finds difficult to explain. "We consistently got smaller grain size in Queensland compared to the same varieties grown in Western Australia and Victoria. Despite this, the Queensland grain yielded more flour, about 2. 5 per cent more.
"This supports evidence comparing UK and Canadian grain where the larger grain didn't always produce more flour. It's something that may be significant in the current breeding push for larger-grained varieties.
"Interesting too was the fact that while Prime Hard varieties in Queensland and northern NSW produced the same protein as the varieties grown to the south, there was a difference in the baking quality of the flour. Southern Prime Hard was most suited to baking and the northern Prime Hard to noodle making. "
Each of the varieties was tested for 12 quality characteristics. "They ranged from the protein content, test weight and kernel weight through to flour colour and a series of measurements of dough strength, and baking quality, the parameters that attract buyers to particular styles of wheat and for which they're prepared to pay. "
Unexpected finding on diversity in WA
On a very practical note the trial has yielded information which could change the delivery system in Western Australia.
"Across the four years of the trials there was more variation in the performance of the varieties within WA than across the whole of the country. The West is currently considered one delivery zone. The findings suggest that a northern and a southern delivery zone could highlight quality differences that would be useful to marketers, " says Mrs Allen.
Contact: Mrs Helen Allen 02 6938 1802
Region National, North, South, West