The improvement of Borage as a commercial source of gamma-linolenic acid

Background: Market demand for of the essential human fatty acid supplement, gamma-linolenic acid (GLA) is increasing and borage is being more widely grown as an alternative plant source to the traditional source of GLA, evening primrose. Commercial yields of borage seed are low (around 300kg!ha) due to the lack of development of improved commercial cultivars.

Only limited investigation has been conducted in Australia, with early Canadian phenotypes still being used in New Zealand and Australia today, with erratic and risky production consequences. Our industry partners, Willala Agricultural Pty Ltd, see opportunity for production of this crop in Australia and increased sales of product if commercial yields and their reliability can be lifted through selection of improved plant type and agronomic research and development.

Objectives: The project seeks to increase the commercial yield of GLA from borage, through selection among introduced lines for improvements in plant type, such as determinate growth, harvest index, harvestability and yield of oil and GLA.

Work undertaken to date: The Tasmanian Institute of Agricultural Research in conjunction with Willala Agricultural Pty Ltd, have acquired borage seed lines from within Australia, Europe and North America. Further acquisition of genetic material has continued since 1998 as opportunities have arisen. These lines have been maintained in isolation plantings. In 1999-2000 the lines were evaluated in a replicated trial. The major part of this project's work in the 2000-2001 season was a further replicated experiment to gain more comparative data on promising lines identified in the 1999-2000 season, together with new lines. Overall, seed yields were lower than in 1999-2000 but oil content was higher. GLA percentages of oil, on average, were similar to the previous year. The results have shown enough consistency in the seed yields of lines between the two seasons to verify the identity of those lines performing best under local conditions. Some of the recently acquired lines showed promise, with a local collection returning the highest yield in the trial. Encouragingly, this year's ranking of lines with respect to oil content and GLA fraction of total oil (fatty acids) was very consistent with that found in the previous year. Attempts to cross some lines, which performed well in the comparisons, have been unsuccessful to date.