Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/10/2003
Publication Date: 10/15/2003
Citation: TOMASI, P.M., FERRIE, A.M. 2003. MICROSPORE CULTURE IN GENUS LESQUERELLA. ASSOCIATION FOR THE ADVANCEMENT OF INDUSTRIAL CROPS CONFERENCE. p. 72.
Technical Abstract: In the cultivated species of Lesquerella, L. Fendleri, the variability of the hydroxy fatty acid (HFA) trait is limited to approximately 60% lesquerolic acid. Seeds from other Lesquerella spp. contain elevated lesquerolic acid quantity. Introgression of these wild variability is currently being attempted by production of interspecific amphidiploids within the genus. Another potential breeding option to increase HFA variability is to induce point mutations within cultured microspores via chemical mutagenesis. If successful, the labor-intensive alternative of mutagenizing diploid seed embryos and selfing them for several generations to express the mutant phenotypes would be avoided. Haploid plants obtained through microspore culture and doubled with the use of colchicine (diphaploids) are homozygous in one generation compared with the several generations required to produce nearly isogenic lines. Dihaploid plants would also aid in the development of genetic mapping populations. Therefore, the objective of this preliminary study was to evaluate the factors affecting microspore culture in order to determine whether haploid embryos could efficiently be produced from several different species of Lesquerella. In the cultivated species, L. fendleri, microspores from 12 plants grown at 20/15 degrees C were isolated from four classes of bud sizes (2-3, 3-4, 4-5, and 5-6 mm) and plated at three densities (25,000 50,000, and 100,000) in four different NLN carbohydrate media (sucrose, glucose, maltose, and trehalose) and two different NLN media containing 25% PEG instead of the carbohydrate source. Floral buds less than 4 mm long from four other wild species including L. auriculata, L. densipila, L. lindeimeri, and L. pallida were also cultured at the three different densities in the same four carbohydrate media. For the species L. pallida, L. auriculata, and L. densipila, the floral buds were sampled from two, five, and six plants, respectively. They were grown in two different temperature regimes of 20/15 degrees C and 15/10 degrees C. Only two plants of L. lindheimeri from the warmer chamber were used to sample buds. Depending on the number of plants available and the buds available from each species, the microspores were suspended in either 2.5 ml of media in 60 x 15 mm or 10 ml of media in 150 x 15 mm Petri plates. All cultures were dark-incubated at 32 degrees C for 3 days. After the initial heat shock treatment, the cultures were placed into a 24 degree C incubator in the dark and were scored for embryo development. The amount of embryogenesis and the efficiency of each microspore culture treatment on this limited number of selected Lesquerella species will be presented.