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Variation in Vernonia galamensis flowering characteristics, seed oil and vernolic acid contents

Thompson, A.E., Dierig, D.A., Kleiman, R.
Industrial crops and products 1994 v.3 no.3 pp. 175
height, plant characteristics, Vernonia, germplasm, long chain fatty acids, seed oils, flowering, variety trials, genotype, chemical constituents of plants, oilseed crops
Considerable variation in plant and flower characteristics was observed among seventeen accessions of the Vernonia galamensis (Cass.) Less. complex, including representatives of all but one subspecies. With the exception of ssp. nairobensis, a high percentage of plants of all accessions had flowered by 121 days after planting (DAP) in Arizona on the 9th of January. Mean days to flower for various accessions varied from 37 to 121 days, and those flowering by 121 DAP had mean numbers of capitula ranging from 0.1 to 86 per plant. Fully mature capitula on accessions ranged from 0 to 55%, and plant height varied from 23 to 88 cm at 121 DAP. Seeds of five accessions from three subspecies harvested at full maturity had significantly higher oil and vernolic acid contents, and seed weights than comparable samples harvested at a less mature stage when involucres surrounding maturing seeds were still green in color. Seeds of uniform lots of the day-neutral accession of V. galamensis ssp. galamensis var. petitiana [A 20295 (V 029)], grown at six locations throughout the United States, had highly significant differences in oil percentage (34.5-44.3%), vernolic acid content (61.0-80.0%), and seed weight (1.87-2.91 g/1000). Although environmental factors play a significant role in seed oil and vernolic acid contents, and seed weight, there appears to be no serious constraints to the ultimate domestication and commercialization of vernonia for production in temperate areas. However, considerable genetic improvement is required, and further evaluation, selection, and development of germplasm within various climatic and geographical locations will be necessary to maximize adaptation and yield.