Buckwheat ideotypes for three Australian growing regions

A project undertaken at the Department of Natural Resources and Environment, Ballarat, Victoria, and supervised by C Bluett

Buckwheat is a broadleaf plant belonging to the Polygonaceae family and bears no relationship to true wheat. Originating in Asia, buckwheat has been grown in Australia since the early 1980s.

Buckwheat is known for its health benefits and has been referred to as the ‘meat of the fields’ because of the high protein levels in its seeds and leaves. Worldwide production of buckwheat during 2000 was 2.7 million tonnes , with China producing 1.6 million tonnes. By comparison, Australia was expected to produce approximately 8000 tonnes of buckwheat in the 2000–01 season. Australia currently exports the majority of its buckwheat to Japan for the production of soba noodles, with the remainder consumed locally in various cereals and health products. A major benefit in growing buckwheat for export in Australia is our ability to produce a crop at times when supplies and quality of seed from Northern Hemisphere sources are low.

The Buckwheat Ideotype Project is trialling varieties obtained from Canada, Japan, Slovenia, the Czech Republic, Hungary, Austria, the Russian Federation and China to determine which varieties perform well under Australian conditions. At present, 130 varieties are available for testing. Extensive field trials of 25 varieties are being conducted in Victoria and New South Wales. A further 16 varieties are under investigation in Armidale, NSW. It is hoped that a small selection of varieties can be recommended that would be suitable for growing in different regions of Australia.

The effect on seed set of the application of gibberellin, a plant growth regulator,  is being studied in two commercial varieties, ‘Botansoba’ and ‘Hitachi’. It is hoped that the application of such materials may have a positive effect on seed retention, thus increasing yield. A literature review indicated that that variations in plant density can affect on yield. Previous work on buckwheat sowing rates has revealed  little if any increase in yield at particular sowing rates. A current trial aims at determining if plant spacing allows better seed set in flower clusters found in the branches.

As part of the variety trials, growth under rainfed and supplemental irrigation conditions is being investigated, to help establish the benefits of irrigation and to determine if there are certain varieties that will perform better during drier periods, when irrigation is not always possible.

The ideal buckwheat plant is one that produces a large seed with a high protein level and stable moisture content. One quality parameter used by the Japanese importers is ‘green colour’, the colour of the outside of the grain. This is a desirable characteristic because it is related to the quality of the noodle produced from the flour.

Buckwheat is susceptible to frost and heat, displays high variation in yield, flower numbers and seeds set between plants and plots, and is prone to lodging (falling over) late in its maturation phase. From growth cabinet experiments on temperature, its ideal range is 13°C to 26°C with a longer morning period in the 18°C to 21°C range being desirable for the pollination and fertilisation of flowers. Night temperatures under 10°C result in reduced internode lengths, leaf area and flower bud formation. Night temperatures in Armidale can be as low as 3°C, with several nights in January reaching only 9°C. Consequently, cold temperature damage was evident in some varieties tested in Armidale. Day temperatures above 32°C cause loss of flowers and seeds but overall damage to the crop can be limited if there are only a few consecutive days with maxima above 32°C. This is because the plant flowers continuously during its reproductive life. Buckwheat’s sensitivity to temperature restricts its sowing regime to areas above 800 m or near coastal areas in southern Victoria. Even when restricted to such areas, the microclimate can have a great effect on production, as was seen in the northern tablelands of NSW in 1998–99. An area of buckwheat near the escarpment 20 km east of Armidale had higher humidity levels than those present in Armidale itself. The result was a reduction of yield because of an unknown pathogen that attacked the seed coat. Accurate climate prediction is required to determine whether buckwheat should be sown in a particular area for a particular year.

With high monetary returns possible for good quality seed and demand for its positive health benefits, buckwheat remains a promising crop for Australia, despite current problems of cultivation. Further work is planned in plant nutrient and breeding in Australia. Current advances in buckwheat research overseas are another primary source of information and seed for a future industry in Australia.