Consumption of Echinacea, one of the most popular botanical supplements, continues to expand in the United States. In addition, organic herbal products have captured a large share of the botanical supplement market. We evaluated commercial organic production of the three most-important medicinal species of Echinacea, E. angustifolia DC, E. purpurea (L) Moench., and E. pallida (Nutt.) from two seed sources. Plants were grown in the field for 3 consecutive years. We found that, during the first year, screen cages were associated with enhanced post-transplanting establishment. Growth of E. angustifolia was not affected by either production system or seed source after 3 years, and yields were equivalent for years 2 and 3 for this species. Growth of E. purpurea was affected by production system, but not by seed source, during the first 2 years. In year 3, neither seed source nor production system affected growth of E. purpurea. Yield of E. pallida was greater in the open field the first year; no difference between production systems was found during the second; and, by the third year, plants growing in screened cages produced more than plants growing in the open field. Production system affected yield of E. purpurea only during year 2, and yield was greater in the open field than in screened cages. Echinacea plants in the open field, however, were more affected by aster yellows disease, with an infection rate of 17% for E. purpurea in the open field compared to 3% under screen cages. Based on these results, in areas of aster yellows incidence, excellent Echinacea root yields can be obtained under screen cages using organic seeds.
Fredy R. Romero, Kathleen Delate, and David Hannapel
Fredy R. Romero, David J. Hannapel, and Kathleen Delate
Echinacea is one of the best-selling medicinal plants in the United States. It was historically harvested from wild populations, but its demand has increased so significantly that commercial production has become a necessity to supply the increasing demand and to protect wild populations. The medicinal properties of echinacea are associated with secondary metabolites that are produced mainly in the roots. Hairy roots, induced by the Ri plasmid of Agrobacterium rhizogenes, have been produced in other crops as alternative sources of secondary metabolites that commonly are produced and synthesized in the roots of mature plants. This method of production offers some advantages over traditional agricultural systems, such as the possibility of producing novel compounds year-round. The overall goal of this project is to explore the utility of hairy root cultures (mediated by A. rhizogenes) as an efficient, alternative, and enriched source of secondary compounds with medicinal properties, such as alkamides, flavonoids, and caffeic acid derivatives. We have been successful in transforming roots from E. angustifolia, E. pallida, and E. purpurea plants, and confirming the presence of rol ABC genes in hairy roots using molecular techniques. Roots from control plants show no active growth under dark conditions, whereas transformed roots from E. pallida and E. purpurea show a low degree of branching with a slow growth rate on solid media under darkness. However, transformed E. angustifolia show a faster growth rate and higher degree of branching under the same conditions. Currently, we are working on the optimization of the growing conditions of the transformed roots and will proceed to the biochemical analysis phase of the project.
Fredy R. Romero, Kathleen Delate, and David J. Hannapel
With the increase in popularity of echinacea as a botanical supplement, organic production of this herb continues to grow. Echinacea seeds typically show a high percentage of dormancy that can be broken by ethephon or gibberellic acid, but these methods are not accepted in organic production. We examined in three experiments the effects of varying seed source and germination conditions on echinacea growth. To determine the efficacy of nonchemical treatments, we evaluated the effect of light with and without cold-moist stratification on seed germination of the three most important medicinal species of echinacea, E. angustifolia, E. purpurea, and E. pallida. We used cold-moist stratification under 24 h light, 24 h dark, and 16/8 h (light/dark) to break seed dormancy. We found that germination was enhanced in seeds from a commercial organic seed source, compared to a public germoplasm source. When seeds were not cold-moist stratified, light increased germination in E. angustifolia only, suggesting differential dormancy among the three species. We found that when seeds were cold-moist stratified under 16–24 h of light for 4 weeks, the percentage and rate of germination increased 10% over the control, suggesting this method as an alternative to chemical seed treatments.
Fredy R. Romero*, Richard J. Gladon, and Henry G. Taber
Impatiens (Impatiens wallerana Hook. f.) is the most important annual bedding plant in the US, based on wholesale dollar volume. Production of high-quality plants requires optimization of the nutrition regimen during growth, especially the total nitrogen (N) concentration and the ratio of N sources. Our objective was to determine the N concentration and ratio of N sources that optimize bedding-plant impatiens growth and development. We used four N concentrations (3.5, 7, 10.5, and 14 mmol·L-1 of N) in factorial combination with four ratios of nitrate-N (NO3 --N) to ammonium-N (NH4 +-N) (4:0, 3:1, 1:1, and 1:3). Application of treatments began at day 30, and every-other-day applications were conducted until day 60. From day 60 to day 70 only deionized water was applied. N concentration and source displayed interation for most growth parameters. When N was supplied at a concentration ≤7 mmol·L-1, the NO3 --N to NH4 +-N ratio did not affect growth. When N was supplied at a concentration ≥10.5 mmol·L-1, a 1:3 NO3 --N to NH4 +-N ratio yielded the greatest shoot dry weight, shoot fresh weight, plant diameter, and number of flower buds per plant. With a NO3 --N to NH4 +-N ratio of 4:0, these growth parameters decreased. To produce high-quality, bedding-plant impatiens, N should be applied at NO3 --N to NH4 +-N ratios between 1:1 and 1:3 in combination with an N concentration of 10.5 mmol·L<-1 at each fertigation from day 30 to day 60 of the production cycle.
Fredy R. Romero, Kathleen Delate, and David J. Hannapel
Organic production of one of the most popular botanical supplements, Echinacea, continues to expand in the U.S. Echinacea seeds typically show a high degree of dormancy that can be broken by ethephon or gibberellic acid (GA), but these methods are currently disallowed in organic production. In order to determine the efficacy of nonchemical seed treatments, we evaluated the effect of varying seed source and supplying light, with and without cold-moist stratification, on seed germination of the three most important medicinal species of Echinacea, E. angustifolia DC, E. purpurea (L) Moench, and E. pallida (Nutt.) Nutt. Treatments included cold-moist stratification under 24 hours of light, 24 hours of dark, and 16/8 hours of light/dark to break seed dormancy. We found that germination was greater in the E. purpurea and E. pallida seeds from a commercial organic seed source compared to a public germplasm source. When seeds were not cold-moist stratified, 16 to 24 hours light increased germination in E. angustifolia only. Echinacea angustifolia, E. purpurea, and E. pallida seeds that were cold-moist stratified under 16 to 24 hours of light for 4 weeks had a significantly greater percentage and rate of germination compared to seeds germinated in the dark. Therefore, cold-moist stratification under light conditions is recommended as a method to break seed dormancy and increase germination rates in organic production of Echinacea.