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Simon, J.E., N. Beaubaire, S.C. Weller, and J. Janick. 1990. Borage: A source of gamma linolenic acid. p. 528. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Borage: A Source of Gamma Linolenic Acid

James E. Simon, Nancy Beaubaire, Stephen C. Weller, and Jules Janick

Borage (Borago officinalis L.) is an annual herb of recent interest because the seeds are a rich source of gamma linolenic acid (GLA; gamma-18:3Δ6,9,12). As an intermediate fatty acid in the biosynthesis of prostaglandins, GLA, an unusual fatty acid, is of medicinal value. The oil also appears promising in treating atopic eczema. GLA is obtained principally from seeds of the evening primrose (Oenothera biennis) and selected Ribes spp., although borage seed appears to be the highest known plant source of GLA (17-25% gamma-18:3 from a total seed oil content of 28-38%).

Large-scale commercial production of this crop presents unique challenges because of the plants indeterminate vegetative growth, lack of concentrated flowering and seed set and non-uniform seed maturation. Since 1984, we have investigated borage seed production and GLA metabolism. Field studies were conducted to determine the optimum plant population and nitrogen levels and a prototype mechanical harvester to vacuum seed from the soil surface was built. Experimental seed yields of 753 kg/ha were obtained when multiple nondestructive harvests of seeds were periodically collected from the soil surface, plus a single destructive harvest where plants were cut and seeds harvested. Simulation of a single destructive harvest yielded only 35-40% of the total potential seed yield because of significant seed loss due to seed shattering.

Borage is susceptible to a wide range of insects and disease pests, and is a weak competitor with weeds. Supporting weed control studies identified several promising preemergent herbicides and other compounds that could eradicate the plant No satisfactory postemergent herbicides were identified.

Studies on the genetic variation of seed lines indicated a wide range of total fatty acids and GLA content. Nonshattering types were not found among the more than 50 accessions evaluated. The development of nonshattering seed fines high in fatty acid and GLA would overcome the present production limitations. However, in the interim, the refinement of a seed harvesting unit which can follow a mechanical combine could make the commercial production of borage a more attractive enterprise.

McDaniel, R.G. 1990. Breeding arid-adapted pyrethrum for insecticide production in the desert southwest. p. 529. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Breeding Arid-adapted Pyrethrum for Insecticide Production in the Desert Southwest

Robert G. McDaniel

Dried pyrethrum flowers are a source of biorational insecticides called pyrethrins which show minimal mammalian toxicity and biodegrade rapidly in the environment. In combination with synergists, pyrethrins are extremely effective for control of insects in human habitations, dairy and horse barns, and food manufacture. At present, all pyrethrins used in the United States are imported. Most are supplied in bulk by East African Countries including Kenya. These sources can be very unreliable, which in turn precipitates wide swings in supply and price. This limits the utility of pyrethrins in domestic pesticides.

Following an eight year breeding program we have, developed pyrethrum (Chrysanthemum cinerariaefolium) germplasm adapted to environmental stresses inherent to desert irrigated agriculture. Moderate winters, combined with wide differences in day/night temperatures (a result of the dry desert climate) somewhat mimic the high elevation equatorial environments of East Africa and Equador where high pyrethrin contents are achieved. Arid adapted, stress-resistant pyrethrum clones have been bred which show a good balance of pyrethrins and which yield greater than 2% pyrethrins (dry weight basis) analyzed by HPLC. At Arizona latitude, pyrethrum behaves as a perennial showing a single flush of blooming in April. Simultaneous flowering makes mechanized harvesting feasible. Favorable climatic conditions coupled with intensive irrigated agriculture technology of the American Southwest make it probable that C. cinerariaefolium will become a viable perennial crop in Arizona. It is hoped that our work will promote new domestic production of this high value insecticide crop.

Last update March 31, 1997 aw