Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/1995
Publication Date: N/A
Interpretive Summary: Yield losses in Lesquerella fendleri often result when the crop is not harvested at the appropriate time. Losses result from seed shattering or reduced oil content and quality due to excessive seed desiccation. The effect of various plant population densities and harvest dates was studied at the University of Arizona, Maricopa Agricultural Center. Oil content and quality were not affected by the various population densities, except at the early harvest date when there was higher seed moisture. A large effect on oil content and quality was observed between various harvest dates. The highest oil yield resulted from the second to last harvest, in early June. The final harvest was virtually the same among density treatments. This study will help the seed producer obtain optimum yields and maximize crop profits. The acceptability of lesquerella as a new industrial crop should also improve.
Technical Abstract: Limitation of yield losses occurring during harvest of Lesquerella fendleri, as results of seed shattering and reduced oil content of excessively desiccated seed, may be accomplished through appropriate choice of harvest dates. This research was undertaken to study the effects of harvest dates and plant populations on oil yield and composition in Lesquerella fendleri. Mechanically seeded field plots of Lesquerella fendleri were thinned at 103 days after sowing (DAS) to density treatments of 250,000; 500,000; 750,000; 1,000,000; and unthinned control of 1,500,000 plants/ha. These plants were grown in 1993-94 at The University of Arizona Maricopa Agaricultural Center in central Arizona, and were harvested at 203, 229, 243, and 264 DAS. Eight fatty acids, contributing 87-96% of mature seed oil, were investigated. At 203 DAS, the 750,000 plants/ha treatment produced the highest oil yield at early harvest, although this oil and that from the 1,000,000 plants/ha treatment, were devoid of auricolic acid. During this period, the major contributing fatty acids to oil content were oleic, linoleic, linolenic, and lesquerolic. Harvest at 229 DAS resulted in an increase in oil content for all treatments except 750,000 plants/ha. Lesquerolic acid was the dominant contributor of this oil for the unthinned control. At 243 DAS, higher oil contents were observed in the 250,000, 750,000, and 1,000,000 plants/ha densities, with lesquerolid acid again the dominant fatty acid. At final harvest (264 DAS), lesquerolic acid content was virtually the same among density treatments.