Plants that are the staple food of some animals can be deadly to others. Many plants have properties that lie somewhere between the extremes of toxic and safe. Vetch is one of these.
Common vetch is useful to farmers as a versatile nitrogen-fixing crop in cereal crop rotations. The plant grows particularly well in southern Australia and has also been used as feed for cattle and other ruminants for many years, but its seeds contain about 1.1% of a known nerve toxin that is harmful to monogastric (single stomach) species such as pigs and poultry.
Now, a team of Adelaide University scientists led by Dr Max Tate at the Waite campus, has successfully produced a low toxin white-vetch grain that has offers considerable health benefits and economic possibilities.
Details of the new variety, which has the potential to improve marketing opportunities for the grain, will be released in a talk on January 31 at the 10th Australian Agronomy Conference in Hobart.
"Classic Mendelian plant breeding techniques have allowed us to reduce the toxicity of the grain by nearly two thirds, to 0.4%," Dr Tate explained. "We have used a rapid new selection procedure to produce a series of easily recognised, white seeded varieties which cannot be confused with red lentils; a completely different plant," he said.
In the past, these red lentils have caused more than a few problems. Dr Tate earned an international reputation in the 1990s when he voiced his concern at the export of a toxic Australian feed vetch as a cheap substitute for food grade lentils. According to Dr Tate, such exports to third world countries had the potential to cause serious health problems.
Exposure of the vetch/lentil substitution issue stalled the vetch grain export industry in 1993, with import bans imposed by India, Saudi Arabia and Egypt. In 1998/99 another outbreak of orange vetch exports from Australia caused Sri-Lanka, Pakistan and Bangladesh to ban their importations of Australian vetch.
"Worse still," said Dr Tate, "the fledgling and highly valued red lentil industry, which was non-existent in 1993, was also damaged because of the consumer's difficulty in distinguishing between orange-vetch and red lentils."
Dr Tate expects that fully adapted, high yielding, low toxin white-vetch varieties, which his team hopes to develop, could supersede the current orange seeded lines. "Should that occur," said Dr Tate, "Australia's vetch grain production industry will expand rapidly, and finally put a stop to the repeated substitution of the toxic orange-vetch grain for food-grade red lentils in overseas markets."
Early trials with the new strain have been very promising. "Feeding trials at the Pig and Poultry Production Institute on Adelaide University's Roseworthy campus have shown that low toxin (<0.45%) lines of common vetch, can be tolerated by three week old chicks," said Dr Tate. "High toxin lines can not."
Dr Tate and his team of PhD research students developed a fast infrared analysis system and tested over 3000 accessions from around the world in a search for naturally occurring low toxin vetches.
The project was funded for two years by the South Australian Grains Industry Trust Fund and was carried out in collaboration with Dr Glenn McDonald and plant breeder Dr Doza Chowdhury. Their method followed what Dr Tate calls "the classic work of J S Gladstones of the University of WA" which now underpins that state's multi-million dollar lupin industry, worth US $190,000,000 in 1996.
"With the new white-seeded low toxin varieties, the key problem limiting entry to the mono-gastric feed market is removed," said Dr Tate. "By extending the versatility of vetch, this can only be good news for farmers"
Dr Max Tate Phone: 618-8303-7227 (with Voice Mail Box)
After hours: 618-8339-2494; Fax: 618-8303-7109;
Dr Glenn McDonald 618-8303-7358, fax 618-8303-7109;
Conference contact: Ben Thiessen , email: email@example.com