|Ray, Dennis - THE UNIV OF ARIZONA|
Submitted to: Proceedings Assoc for Advancement of Industrial Crops (AAIC) Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: May 16, 2005
Publication Date: September 21, 2005
Citation: Dierig, D.A., Tomasi, P., Salywon, A.M., Dahlquist, G.H., Isbell, T.A., Ray, D.T. 2005. Breeding strategies for improvement of lesquerella fendleri (brassicaceae). pp 689-697. In M.J. Pascual-Villalobos, F.S. Nakayama, C.A. Bailey, E. Correal and W.W. Schloman, Jr. (ed.) Industrial Crops and Rural Development. Proceedings Assoc for Advancement of Industrial Crops (AAIC) Annual Meeting, Murcia, Spain, 17-21 September 2005. Interpretive Summary: The lack of domestic sources of feedstock for industrial products such as paints and varnishes, industrial lubricants and fluids adds costs to the end product for consumers. This also causes higher trade deficits which affect our national economy. In this study we examined the amount of natural genetic variability for an important component of the seed-oil of a potential new crop for the southwestern U.S. called lesquerella. We found that the species being commercialized has more variability than previously thought for the quality of the oil and that we can successfully transfer other oil related traits from another species to further improve this crop’s yield. This research should help lower the cost of products that utilize seed oils and therefore help bring this potential new crop into commercialization. Seed companies and growers attempting to establish lesquerella as a new crop will also benefit.
Technical Abstract: The primary objectives for our breeding program for Lesquerella fendleri are to develop varieties with higher seed oil quantities, higher amounts of hydroxy fatty acids (HFAs), especially lesquerolic acid, and to improve seed yields. These traits are seen as having the greatest potential for reducing the cost of the seed-oil. Our breeding program has focused on the natural genetic variability contained within L. fendleri and on the introgression of traits from other Lesquerella species as the two main sources of improvements for new germplasm and varieties. Lesquerella pallida has been used as a source of traits to introgess into L. fendleri. This species was chosen because of its elevated HFA content compared with L. fendleri and because both species have the same n=6 chromosome number. Plants were selected in the A2, A3, and A4 generations (designated as such instead of F2, F3, and F4 because the chromosome number was doubled using colchicine to produce amphidiploids) and some were able to produce seed without ovule culture. Transgressive segregates for the lesquerolic acid content trait were found in A3 and A4 generations where the parental values were approximately 50% and 80%. However, the seeds produced per silique were less than 1. The normal number of seeds per silique for L. fendleri is approximately 10 and for L. pallida, 5. This indicates that although the HFA content trait was successfully introgressed, seed yields have not recovered and will require more generations to restore full seed production, as was the case with canola (Brassica napus L.) which required five generation cycles. We examined the variability for lesquerolic acid content by half-seed analysis within a population of L. fendleri selected for high oil content (33%) and high seed yields (above 40 g /plant). We found lesquerolic acid to range from 46 to 70% in a population of over 900 seeds. We then selected those seeds greater than 62 and less than 53% lesquerolic acid by planting the remaining half-seed of the selected individuals, and then self pollinating. Traits being improved through these breeding strategies will make lesquerella more profitable for industry users and growers, thus enhancing its competitiveness with castor oil (Ricinus commus L.) as a biodegradable oil without the toxic ricin contained in castor.