KENAF & FIBER

Many Alberta farmers are interested in low-THC (D⁹-tetrahydrocannabinol) hemp due to the crop’s potential to diversify agricultural production. Hemp (Cannabis sativa) was tested under Alberta field conditions to evaluate its potential for seed and fiber production. Only cultivars with THC levels below 0.3% (deemed to have no psychoactive effects by Health Canada) were used in the research project.

Soil fertility response (N, P and K) and herbicide tolerance will be reported. Ten cultivars from European breeding programs were evaluated in the black and dark brown soil zones. Plant heights were 2.1-3.4 m (black) and 1.2-2.3 m (dark brown). Total biomass was 14.1-17.3 t ha^-1 (black) and 1.7-2.7 t ha^-1 (dark brown). Seed production in the black soil zone was 700-1,350 kg ha^-1. Seed oil analysis of fatty acid composition and tocopherol content showed a valuable nutritional profile.

The introduction of new crops is often suggested in response to various economic and/or environmental challenges. Producers are advised to adopt new crops to achieve better crop diversification, higher economic returns, and improve environmental impacts.

This research focuses on the economic and environmental feasibility of producing kenaf on Virginia’s Eastern Shore. A mathematical programming model was developed to determine the optimal farming operations for two representative cropping systems in the region. The first system consists solely of wheat and soybean production. The second alternative evaluates a cropping system that produces vegetables in addition to wheat and soybeans. The economic and environmental feasibility of producing kenaf under both systems was evaluated.

A direct comparison of the relative profitability of kenaf and other crops showed that kenaf was not a feasible crop alternative for the region. Equally important, its least potential to reduce environmental impacts did not make kenaf a viable candidate from either an economic or an environmental prospective. Several conditions need to be met before kenaf can successfully compete with other production alternatives on the Eastern Shore. In the wheat and soybean cropping system, kenaf would be feasible if one of the following conditions prevailed: a) its price increased to $120 per ton (our assumption $75); b) its yield increased to 8 tons per acre (our assumption 5 tons), or; c) a processing plant located less than 50 miles away (our assumption 150 mile distance). For a mixed wheat/soybean and vegetable system, kenaf would be feasible if its price were $100 per ton, or its yield was 7 tons per acre, or the raw product could be delivered to a processing plant less than 50 miles away.

Barring other institutional constraints, including the absence of well-developed, competitive markets, the best alternative for adopting this crop on the Eastern Shore is the establishment of a processing plant in the region. Caution is warranted, however, because this suggestion does not address questions of whether there is a large enough volume to justify a processing plant, or adequate water and infrastructure to support that facility, or the environmental impact of processing the raw product.

Can a variety of cotton be developed that would thrive in Pennsylvania? This research project explores that question. Several types of cotton were grown in Pennsylvania fields for two years. Data collected included morphological development, agronomic, and physiological characteristics. Desirable traits were identified within a number of genotypes during year one and hybridizations among those genotypes were attempted during year two.

Most evaluations were conducted using the various cotton fiber types. These cotton types included regular white cotton grown in Arkansas, naturally colored cotton grown in Arizona and Texas, and both naturally colored and regular white cotton grown in Pennsylvania that descended from the plants grown in the other states mentioned. The assorted tests were as follows: seed index, wax extraction, carding and drawing sticky test, staple length comparison, fiber strength, and micronaire (fineness and maturity). All these tests are standard requirements of cotton industry for registration of cultivars and valuable in ensuring that specific cotton cultivars meet the strict standards for spinning, and provide useful information for crop improvement.

Analysis of fiber characteristics (Pearson’s correlation) suggests that wax content and micronaire index have a negative correlation (r = -0.52), wax content and fiber strength have a negative correlation (r = -0.64), and fiber strength and fiber length have a positive correlation (r = 0.72).

Three cotton strains that produce naturally pigmented (colored) fibers have been selected from segregating progeny of interspecific Acala (Gossypium hirsutum L.) by Pima (Gossypium barbadense L.) hybrids. Pigmented fiber variants appear to have arisen spontaneously in the advanced generation progeny, as did many other mutant vegetative and floral characteristics. The distinguishing characteristics of these naturally pigmented cottons are excellent heat tolerance and agronomic plant type. These are evidenced by production data and boll size and numbers as well as high quality fiber characteristics, and consistent fiber colors relatively stable over several successive generations.

All colors have been advanced for at least three generations from pigmented fiber parents that exhibited fiber length of at least 25 mm and fiber strength of at least 25 g per tex. Mean fiber length averaged about 29 mm and mean fiber strength averaged about 29 g per tex across all parents. Micronaire varied widely across breeding lines, locations, and years of production with a normal range between 3.0 and 5.5. The green fibers usually had the finest (lowest micronaire). Three distinct germplasms are presented and discussed: one with cinnamon colored fiber; one with champagne colored fiber; and one with emerald green colored fiber. Results and examples of extensive fiber analyses, spinning tests, and thread and cloth samples are shown.

The purpose of this project is to determine the highest fiber yielding variety of kenaf (Hibiscus cannabinus L. Malvaceae) for cultivation in Tennessee. Interest in the production of kenaf in Tennessee has risen recently because of several influential factors. These consist of interests in the South as a production area by foreign investors, concerns over decreasing pulp supplies, as well as government and consumer demand on the tobacco industry. Because of this and several prominent paper companies expressing interest in purchasing kenaf fiber from Tennessee farmers, Galloway Fields Company, Inc. planted four kenaf varieties on May 15, 1997.

Kenaf, a relative of cotton and okra, is a warm season annual that grows from 8 to 20 feet in three months with one central stalk. The composition of the stalk is made up of bast and hurd, similar to that of industrial hemp. Kenaf is best grown in well-drained soil with high temperatures. Kenaf is highly susceptible to root-knot nematodes and other nematode species. Four kenaf varieties were grown in 1997 to compare yield and nematode resistance. These varieties included Everglades 41 (E41), Everglades 71 (E71), Tainung 2 (T2), and SF459. The first two varieties, E41 and E71, were released by the USDA in 1963. Tainung 2 is from Taiwan and was released in 1962, and SF459 of the USDA and Rio Farms Inc. released in 1994.

Each of the three plots planted contained all four varieties and was approximately 20 feet by 75 feet. Every plot contained four rows of each variety with every row being 30 inches wide and every variety spaced ten feet apart. Within the middle rows, a small section was harvested to get a representative sample and avoid border effect. No chemicals were used on the crop and an attempt was made to analyze its weed suppression abilities. Also, the bulk of the first crop was donated for testing for manufacturing several industrial products.

Although this is an ongoing project, the yield data collected during the summer of 1997 is already going to be put into practice for the 1998 season. From the preliminary data collected, the Tainung 2 variety seemed to outperform the other varieties in three specific areas. The T2 variety achieved quick germination with a consistently high germination rate. The Everglades 41 strain had germination approximately 2 days earlier than the Tainung 2, but the seedlings were few and sporadic. The consistently early germination of the T2 variety led to better weed suppression, as well as more uniform stalk diameter. The T2 variety also achieved larger yield and size. Its average height of approximately 13’ 5" towered 8-11 inches over the other varieties. It also excelled over the other varieties in crude yield. Finally, the T2 variety had the best total plant health and durability. This was observed in color, bushiness of the plant, and the ability to store and utilize moisture and nutrients.

This yield information will be applied in selecting varieties for several projects in west Tennessee and southeast Missouri in the 1998 season. These projects include extensive agronomic research with accredited institutions and production research with agricultural producers.

The Mid-South Fiber Network is a national magazine that features original articles, contact information, university reports, and other information designed to enhance the marketing opportunities for producers of agricultural fibers by presenting new value-added enterprises. The journal also serves as a unique distribution vehicle for agricultural fiber papers and a testing ground for new papers and inks derived from agricultural materials. The fibers currently used in these papers include: kenaf, cotton, flax, and agricultural crop residuals. The Mid-South Fiber Network is supported by a wide range of services designed to bring agri-business, researchers, producers, and industry together.

Agricultural fiber paper is derived from any fiber source, but the most likely candidates include: kenaf, cotton, flax, and agricultural crop residuals. Kenaf (Hibiscus cannabinus L. Malvaceae) is a warm season annual that is related to cotton and okra. It may grow from 8 to 20 feet in three months with one central stalk. Kenaf is best grown in well-drained soil with high temperatures. Flax (Linum usitatissimum) is another plant that can be made into paper. Currently, it is being pulped into fine grades of cigarette and stationery papers. The crop can be grown throughout the North. Flax is grown for seed oil and the fiber makes suitable pulp. Cotton from the genus Gosypium is originally from the tropics, but is grown throughout the South. The crop is the most produced agricultural fiber and is typically used in textiles. Agricultural crop residuals are the scraps of stem left in the field after a grain crop is harvested. Agricultural crops being used for paper include corn and wheat straws.

The Mid-South Fiber Network enhances the work of countless university, private sector, and government research and development programs. The magazine shows new options for consumers that are environmentally safe and of high quality. The magazine also reinforces government policy concerning diversified agricultural opportunities. The industries of the United States are introduced to new materials and marketing concepts that can increase jobs, job safety, compliance regulations, and spur added productivity.

The publication of the Mid-South Fiber Network is an applied study of the viability of agriculturally derived publishing materials in common business settings. The success of this project creates a model magazine for the entire publishing industry.

Crotalaria juncea is an annual crop that provides textile fiber similar to Corchorus sp. Variations in stem length (from 2 m to 4 m) and flowering dates have been observed at different sowing dates and latitudes for the same variety. A photoperiod influence in these observations was clear.

To begin the species characterization using a Hawaiian variety, three sowing dates were made at Buenos Aires (BS AS) (34° 35' S, 58° 29' W, and 25 m o.s.l.) the first year and another three sowing dates in the second year. Emergence dates were: a) First year: 10/14/96, 11/24/96, and 1/1/97; b) Second year: 11/01/97, 12/10/97, and 06/02/98. One sowing (2/2/97) was made in Costa Rica (10° 02' N, 84° 10' W, and 1,060 m o.s.l.) in 1997. The experimental design was similar in both countries. Supplemental irrigations were made in BS AS and Costa Rica. BS AS soil was fertilized with N even though the nodulation was good. Phenological and phenometric observations were made in the two countries, and phenometric observations also made in the second year.

Plants showed a quantitative short day response because flowering dates for the first and second sowing dates in BS AS were 3/10/97, and 3/20/97 for the third date (the first year), the second year: 3/6/98 and 4/19/98. Photoperiod was always short in Costa Rica so that the plants were soon induced to flowering (4/4/97) and achieved a mean height of 94 cm. At BS AS, stem lengths were 100-270 cm. In the first year, some of those plants had a little flower on 12/2/96, but after they aborted, the plants blossomed in March. The second-year first and second sowing dates had some plants with flowers at 1/4/98 and after this date new individual plants appeared with flowers in January and February. In March, all the plants had flowers.

As kenaf (Hibiscus cannabinus L.) production in the United States continues to increase, it is essential to integrate this alternative fiber crop into existing cropping systems. Soybean (Glycine max (L.) Merr.) is now grown widely in the same production areas where kenaf can be successfully produced. A kenaf-soybean rotational system could have long-term economic and pest control advantages, if there are no adverse effects of rotating these two crops.

A three-year field study was conducted at Haskell, OK to determine the effect of six kenaf-soybean rotations on kenaf and soybean yield components. The kenaf cultivar 'Everglades 41' and soybean cultivar 'Forrest' were planted on a Taloka silt loam soil in mid-May and harvested each October. The crops received no irrigation; rainfall was the only source of moisture. The individual kenaf/soybean rotations did not adversely affect the kenaf stalk yields or soybean seed yields. Kenaf stalk yields across all rotational combinations and years averaged 7.9 Mt/ha, whereas soybean seed yields averaged 866 kg/ha. Seasonal rainfall affected soybean growth and yielded more than any effects due to the cropping sequence. A continuous kenaf rotation produced the greatest kenaf yields (9.4 Mt/ha) in the final year. It was determined that either a three-year continuous or rotational cropping system can be used for kenaf and soybean production without reducing crop yields.

Research information is limited concerning the effect of soil moisture, fertility, and cultivar interactions on kenaf (Hibiscus cannabinus L.) yield components.

The objective of this two-year research study in Oklahoma was to investigate the interaction of these factors on kenaf development and yields. The factorial design involved two levels of irrigation (irrigated and non-irrigated), five levels of nitrogen fertilization (0, 57, 114, 171, and 228 kg/ha), and two cultivars (Tainung #2 and Everglades 41). Drip irrigation was used for the irrigated treatments. Fertilizer was manually spread before planting.

Plant populations were unaffected by the irrigation treatments, although additional water did increase plant height, development, stalk percentage, and stalk yields across all other factors. Tainung #2, a deeply divided leaf cultivar, had greater yield components than Everglades 41, entire leaf cultivar. The yield components for both cultivars were adversely affected by nitrogen applications greater than 114 kg/ha.

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MEADOWFOAM

Production of meadowfoam (Limnanthes alba Bentham, Family Limnanthaceae), traditionally grown in the Willamette Valley of Oregon, is currently being attempted in Virginia. Interest in meadowfoam is based on the high proportion of long-chain fatty acids (20- and 22-carbons) in its oil. Meadowfoam oil is characterized by very high levels of mono-unsaturation and very low levels of poly-unsaturation. These characteristics make meadowfoam oil very stable, even when heated or exposed to air. The uses of meadowfoam oil include personal care products such as cosmetics and toiletries as well as industrial applications including lubricants and inks. Meadowfoam oil can also be a replacement for sperm whale oil.

Observation plots of meadowfoam were established during 1992-93 and 1993-94 at Petersburg, Virginia under the New Crops Program of Virginia State University. The meadowfoam planted in this location produced seeds indicating that it may have potential in Virginia. During the 1994-95 season, replicated experiments were conducted with the "Mermaid" to determine yields and to study the effects of nitrogen fertilization on seed yield and oil characteristics. The average seed yield was approximately 495 kg/ha with the highest yield of 634 kg/ha. Oil content ranged from 21-25%. The oil contained an average of 93% long-chain fatty acids (20 and 22 carbons).

These observation studies were followed with commercial meadowfoam production on approximately 4 ha during 1996-97. The average seed yield from this production effort was approximately 457 kg/ha, the oil yield was approximately 26%, and the long-chain fatty acid content of the oil was 97%. The crop was direct-combined and resulted in shattering seed loss of approximately 38%. Additional research showed that row spacing of approximately 15 cm and a nitrogen fertilizer rate of up to 100 kg/ha may be desirable for meadowfoam production in Virginia. During the 1997-98 crop cycle, meadowfoam was planted on approximately 50 ha in cooperation with Oregon Meadowfoam Growers. A tentative meadowfoam production system for Virginia include planting during late November to early December, seeding rate of approximately 28 kg/ha, row spacing of approximately 15 cm, swathing at approximately 42% seed moisture, and combining with a belt-pick up. The results of this production investigation will become available in late June 1998.

Currently, the existing meadowfoam cultivars need pollination by honey bees. The honey produced from the 1996-97 crop was determined to be of high quality by the local bee keepers. Efforts are underway to develop high yielding meadowfoam genotypes that combine the desirable oil characteristics with adaptation to Virginia’s agro-climatic conditions. Additionally, research is also being conducted to develop self-fertile meadowfoam genotypes to eliminate the need for honey bees. The efforts to establish meadowfoam in Virginia are supported by a multi-disciplinary team. Details of these production and research efforts will be presented.

Meadowfoam oil, as a unique source of long-chain, unsaturated fatty acid, has received considerable attention among the new crop scientists. Besides several notable strides in our knowledge of systematics and ecology, the genus Limnanthes has provided wonderful opportunities for genetic research. Germplasm accessions show heritable variation in phenology, breeding system, plant architecture, and oil composition.

Our findings on the genetics of nonshattering, gene-cytoplasmic male sterility, nutlet polymorphisms, oil content, and higher selfing ability are of considerable interest in breeding work. Research at Davis, CA and Corvallis, OR will be reviewed to summarize our current genetic database in relation to the goals of developing higher yielding, inbred or hybrid cultivars with improved plant architecture, nonshattering, and various adaptive features. Both Mendelian and quantitative genetic findings will be presented and new genetic objectives will be discussed. Limnanthes domestication has progressed well given rather small inputs and its story could serve as a good model for many similar projects.

The demand for meadowfoam (Limnanthes alba Benth.) oil is increasing along with the demand for new cultivars to boost seed yields and profits. One of our aims is to increase the supply of meadowfoam oil by increasing seed yield and oil content, decreasing lodging, and developing self-pollinated cultivars. We are using molecular breeding tools to facilitate this process.

A genetic map was produced using inter-subspecific (L. alba ssp. alba x L. alba ssp. versicolor) backcross progeny, inbred parent lines (Mermaid S₅ and OMF-64 S₅), and amplified fragment length polymorphisms (AFLPs). The map is presently comprised of 110 AFLP markers spanning five linkage groups (x = 5). Mermaid S₅ is a cross-pollinated L. alba ssp. alba line. OMF-64 S₅ is a self-pollinated L. alba ssp. versicolor line. The two parents were highly polymorphic. This greatly facilitated the development of the map and should greatly facilitate marker-assisted selection in inter-subspecific crosses.

BC₁S₁ progenies were produced and field tested in 1997-98 at Corvallis, Oregon and segregated for self-pollination, seed yield, oil content, biomass, flower, stem, and leaf morphologies, plant height and diameter, and maturity. The progenies were planted in the open and under insect-proof field cages. The latter were used to phenotype the progeny for self-pollination. Genes affecting self-pollination, seed yield, oil content, and other traits were mapped in this study.

We will report the quantitative trait loci (QTL) mapping results and describe how this knowledge is being used for molecular breeding in meadowfoam. The findings reported in this study should give us tools to accelerate cultivar development more precisely and rapidly shuffle genes between the two subspecies, and find favorable alleles in exotic germplasm.

Meadowfoam (Limnanthes alba Benth.) produces a seed oil with novel chemical and physical properties. L. alba subspecies have different wild-type fatty acid profiles. L. alba ssp. versicolor produces significantly more erucic acid (22:1) and significantly less dienoic acid (22:2) than L. alba ssp. alba. This difference has ramifications for marketing and cultivar development. Cultivars presently must have the L. alba ssp. alba fatty acid profile to meet market requirements. Whether the marketplace can tolerate oils with the L. alba ssp. versicolor fatty acid profile is not known. The 22:1 and 22:2 content differences between the subspecies are caused by a dominant gene (E). Genes with quantitative effects could be segregating in intra- and inter-subspecific populations.

We used the genetic map of meadowfoam to map the E locus and search for the quantitative trait loci (QTL) affecting 22:1 and 22:2 content. The genetic map was built using backcross progeny from a cross between L. alba ssp. alba and L. alba ssp. versicolor inbred lines (Mermaid S₅ and OMF-64 S₅, respectively). OMF-64 S₅ was used as the recurrent parent.

The L. alba ssp. alba parent produced 8% 22:1 and 30% 22:2, whereas the L. alba ssp. versicolor parent produced 24% 22:1 and 9% 22:2. The phenotypic distribution for 22:1 and 22:2 content was 90:90; thus, the E locus segregated 1:1 (p = 1.0) in this sample. Erucic and dienoic acid content varied among dominant (E_) and recessive (ee) class progeny. The differences may have been caused by QTL or non-genetic factors or both.

We will report the findings of a QTL analysis to address this question. Regardless, cultivars with the prerequisite fatty acid profile can be developed by selecting for and fixing the E allele. The E locus could be linked to genes affecting other economically important traits. This will be assessed in a companion gene mapping study.

Profit incentives for producers, buyers, brokers, processors, manufacturers, and retailers can be critical in driving Research & Development for a new crop and products it produces. Costs of production may strongly impact the profit margins for producers, and thus can strongly influence the economic competitive position of a new crop with respect to other crops available to farmers to grow.

Oil is the prime economic product sought from the seed of the new crop meadowfoam. Thus, oil yield per acre is the prime measure of crop economic output. Many factors may significantly impact meadowfoam oil yield per acre. Example factors may include the cultivar used; seeding dates; seeding rates; row widths; nitrogen fertility management; weeds; insects; diseases; pesticide toxicity; extreme temperatures; insect pollination; water deficit stress; harvest timing; and harvest losses from swathing, swath pickup, and combining. Several of these variables may interact, but their interrelationships to oil yield per acre may not yet be known or well understood. The components of oil yield are seed yield and oil content of the seed. Therefore, increased oil content of new cultivars may increase oil yield per acre even if optimum production practices have not yet been established.

The presentation will include: 1) photos of near-infrared transmittance spectroscopy (NITS) equipment used for the nondestructive single-seed analysis of oil content in meadowfoam, 2) data from single-seed measurements that illustrate the kind of selection options made possible with this technology, and 3) literature citations to the detailed description of the development of this tool.

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MEDICINAL

St. John’s wort (Hypericum perforatum) is a successful antidepressant drug with high demands worldwide. Chile exported 4,000 tons of this herb in 1997, which were all collected from the wild. Cultivation is just starting in Chile, but more information on crop management is needed.

A trial was conducted at Chillán, Chile (36° 26’ S, 72° 06’ W) to evaluate the effect of nitrogen fertilization on St. John’s wort. The crop was sown on August 5, 1997 and first harvested in January 1998. The crop was irrigated and chemical and hand weeded. Nitrogen treatments were 0, 37.5, 50, 75, 100, and 150 kg ha^-1. Each amount was applied as sodium nitrate immediately before seeding. Nitrogen application was repeated in October because excessive rainfall occurring immediately after seeding leached the nitrogen. The experimental design was a randomized complete block with four replications.

Evaluations conducted were: Top 25 cm biomass yields; flower, leaf and stem composition; hypericin content of flower, leaf, and stem; threshed yield (based on dried flowers and leaves from the 25-cm biomass harvest).

Nitrogen increased the biomass yield up to 100 kg ha^-1 without decreasing the hypericin content. A biomass yield of the top 25 cm reached approximately 4,000 kg ha^-1. This yield is considered good for the first harvest because the plants were only five months old. Highest hypericin content was found in the flowers followed by leaves and stems. The stems have small amounts of hypericin. Therefore, threshing out the stems and keeping the leaves and flowers to increase quality is important. Threshing yields decreased as nitrogen rates increased mainly because plants with higher nitrogen rates had the higher moisture content.

Lippia alba, family Verbenaceae, popularly called "cidreira"or "melissa" in Brazil, is one of most important medicinal plants used by the Brazilian population. Its therapeutic actions include somatic, sedative, antidepressant, and analgesic activities.

This species occurs in South America, mainly Brazil and northern Argentina, in sandy soils along margins of rivers, and in tropical and subtropical areas. In Brazil, it grows all over the country and is cultivated in some regions to provide raw material for medicinal products. Different natural varieties are found in several areas in northwest Brazil. In Brazilian Amazonia, local people know two ethnovarieties using both for different diseases. One of these varieties is called "cidreira" and is used as an analgesic and sedative. Another variety, "carmelitana," is used for stomach aches and digestive problems.

It is a shrub with a quadrangular branch reaching 1.7 m tall. The leaves are membranaceous, petiolate, pubescent with a strong flavor. Its limbs have variable forms with pointed apex, cuneiform or decumbent base, and serrated or crenated border.

Its secondary metabolites are flavonoids, alkaloids, and mainly essential oils produced by glandular hairs in the epidermis and the cells of the mesophyll. In recent researches, the main compounds of essential oils observed in leaves of the species are terpinene, p-cymene, caryophylene, myrcene, geraniol, and neral.

Agricultural researches conducted in the Parana and São Paulo states showed important characteristics to its cultivation and development. Plant propagation is vegetative, using stem cutting about 20-25 cm long and 0.5 cm diameter. The planting in certain areas has to done about 40 days after the preparation of the stem cuttings. Plant spacing depends on the variety used. The recommended fertilization is 4 kg/ha of organic manure. The foliar biomass yields are about 5 ton/ha in four harvests during an year. The yield of essential oil is about 0.3 - 0.4 %.

Studies on harvesting seasons showed that, in the summer, the leaves at the base section of the stems produced more essential oil than leaves from the apical section. The first harvest can be done four months after planting.

Pergularia tomentosa (Asclepiadaceae) is an endangered medicinal plant indigenous to Saudi Arabia. The plant was shown to produce cardenolides in the roots.

Vigorously growing cell cultures were established from parts of axenic seedlings. Newly established callus cultures from roots produced anthocyanin pigments on MSB5 medium containing NAA in the light, and differentiated into roots on a similar medium in the dark. Hormonal autotrophic suspension cultures were developed that produced a viscous extracellular polysaccharide (ECP) on MSB5 liquid medium. Transformation with Agrobacterium rhizogenes resulted in fast growing hairy roots that spontaneously proliferated transgenic callus. Such callus produced intense anthocyanin pigments on NAA containing medium compared with normal callus. The nature of the ECP and the individual anthocyanin components will be presented.

Khat, Catha edulis Forssk (Celasteraceae), is an evergreen tree indigenous to East Africa and Yemen. The young leaves are habitually chewed to alleviate hunger and fatigue, and for its central nervous system stimulant effect.

Callus cultures were induced from young leaves on MSB5 basal medium (Murashige and Skoog inorganic salts with Gamborg-B5 vitamins) supplemented with 3.0 mg/l of either IBA or NAA. The callus produced dark pigments on both treatments. Callus tissues collected from several subcultures on IBA or NAA containing media were used for extraction and analysis of pigments.

Two orange-colored compounds, tingenone and 2,2-b-hydroxytingenone, were isolated and identified by spectral analysis and by comparison with reported data. The compounds exhibited strong antimicrobial activity against several strains of infectious bacteria (0.3 - 0.6 µg/ml, MIC values). 2,2-b-hydroxytingenone also exhibited significant cytotoxic activity against leukemia (ED₅₀ 0.54 µg/ml) and prostate cancer (ED₅₀ 0.85 µg/ml). The isolated compounds could not be detected in the mother plant grown in the greenhouse.

Based on the economic and medicinal value of their biologically active compounds, E. purpurea and H. perforatum were chosen to test the effects of moderate to severe water stress imposed during different times of the growing season on the concentrations of the medicinally valuable cichoric acid (the predominant root phenolic in E. purpurea) and hypericin (the pigment in the leaves and flowers of H. perforatum).

This study will attempt to quantify aspects of the relationship between water stress and the cellular responses that result in the production of secondary compounds. On a practical level, the investigated species are complementary to current agroforestry management practices such as alley cropping. One objective of this study is to provide useful management techniques to the landowner to grow more economically and medicinally valuable plants with greater concentrations of the desired compounds.

All plants were grown in three-gallon pots and watered with individual drip irrigation during the spring through early summer of the 1997 growing season. The three dry down treatments plus a control that received water were tested from August to October. During this period, water was withheld from selected plants to induce a slow dry down. The selected plants were closely monitored by taking predawn water potential (y_pd) and midday stomatal conductance measurements (gs) to determine the severity and duration of moisture stress. At the end of the season, all monitored plants were harvested, fresh and dry root weights measured, and samples prepared and stored for chemical analyses.

Chemical analyses will consist of standard procedures to determine concentrations of cichoric acid and hypericin. Chemical testing will be conducted after the first season of dry downs and will continue for two additional seasons to quantify the cumulative differences in chemical concentrations that accrue after two and three seasons of water stress treatments. Preliminary data concerning the relationship between level and timing of water stress and the effects on chemical concentration will be presented.

An experiment was conducted to determine the effect of harvest dates on the yield and hypericin content of flowers, leaves, and stems of St. John´s wort grown in Chillán, Chile.

Treatments were seven harvest dates starting before anthesis and until the beginning of fruit formation. The experimental design was a randomized complete block with three replications. To determine hypericin content, chlorophyl was first extracted with sequential extractions with ether, followed by hypericin extraction with ethanol. Hypericin quantification was done with molecular absorption spectrometry at 589 nm. Data collected were subjected to ANOVA analysis and differences among treatments were detected with Tukey´s test.

Threshing yields (dried flowers and leaves from total fresh biomass harvested) increased as harvest dates were delayed reaching its maximum at the beginning of fruit formation. However, biomass yield was at its maximum when the flower petals fell. The highest hypericin content in flowers, leaves, and stems was observed at the beginning of anthesis. Hypericin yield per kg of fresh herb collected was highest at flower petal fall, whereas the maximum hypericin yield per ha was obtained at the beginning of flowering. Results suggested that St. John´s wort harvest must be done at the beginning of flowering when most flowers are in the bud stage and only a few flowers have opened.

Aloe vera is an industrial crop that possesses a gel that affects several biological and physiological activities, such as burn skin healing, prophylactic effect against radiation leucopenia, inhibitory action against some bacteria and fungi, and anti-ulcer activity. The gel is also used for manufacturing cosmetics. The objective of the present study objective is to evaluate the composition and yield of Aloe vera.

Wild plants were collected from the Palma Gorda area, a region close to Saltillo, México. Their compositions were compared with those of garden cultivated plants and fresh, commercial gel products. Plant collections were made during March. They were transported to the laboratory and stored at 4-6°C until analysis. The plants were then washed and weighed. The number of leaves and leaf thickness at three points were measured. For gel extraction, the leaves were cut longitudinally and the gel separated by hand with a knife, weighed, and stored at -20°C. The gel was later freeze-dried and the yield of gel was calculated. Nitrogen and protein contents of the dry gels were determined by the Kjeldahl method. Manganese, iron, sodium, magnesium, and calcium were determined by atomic absorption. Leaf protein content was measured by the modified Bio-Rad method, molecular weight determined by electrophoresis in SDS gel, and Aloin and Aloe-emodin by chromatography.

The results show that the plant weight was between 850-2,500 g. Fresh gel content was 42-55% of the fresh leaf weight. The dry gel weight was 2.2-4.2% of the fresh gel weight. Nitrogen content ranged from 0.28-0.81%, dry gel basis, and the protein ranged from 1.8-5.3%. Elemental analysis values of sodium and manganese were equal to those reported by others. However, the calcium, iron, magnesium, and phosphorus contents were different. Aloin and Aloe-emodin contents will be presented in the full paper.

Sea buckthorn is native to northern and central Europe, and throughout central Asia. Its domestication process started in Russia in the 1930's. In 1986, a project started at Balsgård with the aim to introduce sea buckthorn as a new commercial berry crop in Sweden. Since then, different plant materials have been used in the breeding program.

Out of three different species of the genus Hippophae tested at Balsgård, only the most widespread species Hippophae rhamnoides have survived. Out of six subspecies of H. rhamnoides, only the two with the most northern most native distribution have performed well in Sweden. The two subspecies H. rhamnoides ssp. rhamnoides and H. rhamnoides ssp. mongolica now serve as the base for the breeding program.

Sea buckthorn (Hippophae rhamnoides L.) is a winter-hardy, deciduous shrub with yellow or orange berries. It develops extensive root system rapidly and is, therefore, an ideal plant for soil erosion prevention and land reclamation. The shrub can withstand low temperatures from -43 to 40°C. It is considered to be drought resistant; however, irrigation is needed in regions receiving <400 mm of rainfall per year for better growth.

Sea buckthorn is a dioecious shrub, usually spinescent and 2 to 4 m tall. It has brown or black rough bark and a thick grayish-green crown. Leaves are alternate, narrow, and lanceolate with a silver-grey color on the upper side. Flower buds are formed mostly on the three-year-old wood, differentiated during the previous growing season.

Sea buckthorn can be used for many purposes and has major economic potential. It has been used for centuries in its native Europe and Asia. Recently, it has attracted considerable attention from researchers around the world, including North America, mainly for its nutritional and medicinal value.

Sea buckthorn fruits are rich in carbohydrates, proteins, organic acids, amino acids, and vitamins. The concentration of vitamin C in sea buckthorn fruit, ranging from 100-300 mg/100 g fruit, is higher than strawberry, kiwi, orange, tomato, carrot, and hawthorn. Sea buckthorn is also high in protein, especially globulins and albumins, and fatty acids such as linoleic and linolenic acids. Vitamin E content in sea buckthorn (202.9 mg/100 g fruit) is also higher than wheat embryo, safflower, maize, and soybean.

Medicinal uses of sea buckthorn are well documented in Asia and Europe. Clinical tests on its medicinal uses were first initiated in Russia during 1950's and later in China. Sea buckthorn oil was formally listed in the Pharmacopoeia in 1977. The important pharmacological functions attributed to sea buckthorn oil are: anti-inflammatory, antimicrobial relieving of pain, and promoting regeneration of tissues. Sea buckthorn oil is also touted as a treatment for oral mucositis, rectum mucositis, vaginal mucositis, cervical erosion, radiation damage, burns, scalds, duodenal and gastric ulcers, chilblains, skin ulcers caused by malnutrition, and other skin damages.

More than ten different drugs have been developed from sea buckthorn in Asia and Europe and are available in different forms such as liquids, powders, plasters, films, pastes, pills, liniments, suppositories, and aerosols. Sea buckthorn oil extracted from seeds is popular in cosmetic preparations such as facial cream. In Europe and Asia, many products are made from sea buckthorn, such as tea from leaves, beverages and jam from fruits, fermented products from pulp, and animal feed from leaves, pulp, and seed residues.

A mutant agave clone (Agave vilmoriniana, Berger) has been identified, which is capable of synthesizing commercial levels of steroidal sapogenins. Such steroidal compounds are useful in the production of odor-control formulations, beverage foaming agents, food grade additives, and as resource materials in the manufacture of pharmaceutical drugs.

Agronomic trials of this variant clone have been underway at three Arizona locations for several years. This clone does not produce offshoots, but has been vegetatively propagated by rooting aerial "bulbils" produced on the flower stalks.

Efforts to mechanize nearly all aspects of agave cultivation and harvest have been successful. Growth rate data for this clone as well as appropriate agronomic practices are presented. The thick cuticle of this agave mutant allows the use of RoundupTM herbicide, which, along with cultivation, controls competitive weeds. The ability of this clone to initiate CAM metabolism under stress also makes it quite competitive in the desert high temperature environment. The superior growth rate of this clone has resulted in plants with harvest weights in excess of 136 kg in less than four years following transplanting. Establishment of cultivated agave plantations appears to be economically feasible for the southwestern desert agricultural areas, based upon projections of the input costs and value of the harvested product.

Echinacea is a North American genus with pharmaceutical, insecticidal, and ornamental potential. Its root is commonly harvested from the wild as a commodity for the international medicinal plant trade. The historical and continued harvesting of wild roots and a new development, the harvesting of wild seeds, are having an as yet unmeasured impact on the viability of native populations of the genus.

A comprehensive field survey of the center of diversity of Echinacea, which lies within the continental United States, was conducted in 1997. The purpose was to identify and put into ex situ conservation a representative genetic sample of the 11 recognized taxa of Echinacea, two of which are federally listed as endangered. A total of 88 new accessions have been deposited with the USDA/ARS National Plant Germplasm System with 15 or more projected for 1998.

The full agricultural and economic potentials of the genus Echinacea are far from fully investigated. Its closely related species exhibit high phenotypic diversity and are easily misidentified from each other. Although only three of the species have been demonstrated to have medicinal value, other species within the genus, endemics, and hybrid swarms are being wild- harvested. An overview of the accessions will be presented with emphasis on their agronomic characters and taxonomic variations. The report represents the first scientific survey of this genus in 30 years.

The species Ageratum conyzoides L., Asteraceaes family, is a medicinal plant used for a long time in traditional medicine in several tropical countries of the world. It originated in America and Caribe and also occurs in other tropical countries. It is a herbaceous, perennial species with glandular hairs and secretory channel that produce essential oils. The small and light fruit associated with its aristed papus permits its easy and long range dispersion. In Brazil, it occurs over most of the country and in some area is considered a weed in the cropped lands. However, it is used as medicine in almost all regions of the country.

The aqueous extract of leaves and other parts of the plant is used for the treatment of stomach aches, burns, pneumonia, and arthritis, and as a bactericide and antispasmodic. Recent clinical research in Brazil confirmed positive results for patients with arthritis without any side effects. The aqueous extract was 66% efficient in analgesic relief, 24% in articular mobility with a decrease or disappearance of inflammation.

The plant is also important in agriculture. The extract of the whole plant or leaves is used to modify insect metamorphosis, mainly in Diptera and Hemiptera. Cromens (precocens I and II) present in the essential oil has the ability to produce incomplete juvenile forms or sterile or deformed adults. The extract also has insecticidal properties. A. conyzoides as vegetative cover in citrus orchards increases the presence of predator spiders of leprosis virus vectors. The extract decreases the emergence of Meloidogyne incognita larvae.

Results from agricultural studies in Botucatu, São Paulo, Brazil showed the best method for seed sowing and procedures to follow in the nursery. The seeds are positively photoblastic so that they must be placed on the surface of the substrate. The seedling must be transplanted 30 - 35 days after sowing. Research also showed that higher biomass yield could be obtained when organic manure instead of mineral fertilizer was used.

Leaf yield ranged from 600 to 3,000 kg/ha depending on the growth stage of the plant. The best growth stage to produce leaves and/or flowering stems is pre-flowering. Essential oil yield from the leaves ranged from 0.01 to 0.04 %, and in the flowers from 0.02 to 0.07 %. The cromens content was 85.4% in the leaves and 81.5 % in the flowers. The compound dimetoxiageratocromeno represented 72.0 and 52.0 % of the total cromens in the essential oil of the leaves and flowers, respectively. Ageratocromeno content was 13.4 and 29.5 % of the cromens in the essential oil of the leaves and flowers, respectively.

Consumer preferences and scientific developments are changing and these are leading to a significant adjustment for U.S. agriculture. During the last century, most agricultural research and production were to increase yields of food and fiber. Within the last decade, more attention is being focused on the production of new and alternative crops and their by-products for agricultural, industrial, and pharmaceutical uses.

Many legumes produce economically important organic compounds such as gums, dyes, pharmaceuticals, pesticides, phytochemicals, and many specialty products. However, most legumes have never been or have just begun to be studied for their phytochemical or biologically active components. New reservoirs of commercially valuable materials remain to be discovered.

South Africa is blessed with a vast array of native aromatic and medicinal plant species of economic value. For many years, attempts have been made to exploit the indigenous aromatic plants for use in the pharmaceutical, cosmetics and toiletries, foods and flavor, perfumery, and aromatherapy industries, as well as serving as a vehicle for economic empowerment of the disadvantaged communities.

The paper will highlight the progress regarding the development of new crops from Artemisia afra, Tagetes minuta, Eriocephalus punctulatus, Pteronia incana, Salvia stenophylla, Agathosma spp., Lippia javanica, and other aromatic plant species. Implications for biodiversity within populations in nature and sustainability of agricultural productivity in rural communities will be discussed. The role of various stakeholders in biodiversity conservation will be presented. Examples will be drawn from the Eastern and Western Cape Provinces of South Africa.

Piper hispidinervum is one of most promising Brazilian crops for possible substitution of sassafras oil from the endangered Ocotea pretiosa Ness (Mez.), Cynamomum petrophilum, C. mollissimum, and Sassafras albidum Nutt.

Until the 1960's, Brazil was the major exporter of sassafrás oil in the world. Production has declined since then with the depletion of the natural resource from which it was obtained, wild O. pretiosa in the Mata Atlântica areas of southern Brazil. Governmental restrictions in the late 1980's have resulted in a further decline in its production and export.

P. hipidinervum, called "Pimenta Longa", is distributed throughout South America, especially in the Acre state of Brazil. It is believed to extend into the Amazona state as well as Peru and Bolivia. The plant is frequently found in open fields, colonizing such areas like a "weed." Our recent laboratory studies showed that this plant is positively photoblastic.

The leaves contain high levels, 83-93%, of safrole that is an important raw material for the chemical industry. Two derivatives, heliotropin, which is widely used as a fragrance and flavoring agent, and piperonal butoxide (PBO), a vital ingredient of pyrethroid insecticides, can be obtained. Commercially, it is present in many household fragrances and applications such as floor waxes, polishes, soaps, detergents, and cleaning agents.

Ethnobotanical studies had been showed that it is used by Brazilian rubber-tappers in restorative baths. The safrole is a phenolic ether; allylcatechol methylene ether; allyldioxybenzene methylene ether, which has been used as a topical antiseptic. The sassafras oil price is about US$4 to $6/kg.

The growing techniques and propagation methods developed for its production have possibilities for adoption in the local communities. Mixed planting of P. hispidinervum with other cash crop is a practical possibility and would be economically attractive to growers. Harvesting of this crop before the harvest of the primary crops could provide early cash return. Sustained management is another production alternative in open areas bordering the primary rainforest.

An integrated project among research institutes, universities, governmental and non- governmental establishments on this species could produce a sustainable alternative with environmental and social benefits for the local populations in the forested areas of Acre.

One possible limit to establishing Aloe vera culture in the southern regions of the Mexican state of Coahuila is the low winter temperatures. These may cause the freezing of the lower part (leaves) or even of the whole plant depending on intensity and duration of the low temperatures. Temperatures of -3 to -4°C are common during the night and they frequently continue for several days. The objective of this study is to determine the response of Aloe vera to low-temperature conditions. This information will allow adequate planning in establishing the crop.

Forty Aloe vera plants from the southern region of the Mexican state of Tamaulipas were used. The plants were tagged and transplanted into 10-liter pots containing a mixture of soil, peat moss, and perlite in the same proportional volume. They were then placed in a greenhouse at the University. After six months, groups of four plants were selected to undergo different treatments of -1, -2, -3, and -4°C exposed for 12 h until the temperature causing damage to the plants was detected. After the treatments, the following measurements were taken: leaf damage, gel production loss, leaf thickness, pH of the extracted gel, and tissue damage. The results will be presented in detail in the full paper.

Echinacea (E. purpurea and E. angustifolia) is among the most popular medicinal herbs grown and wildcrafted in the United States. The increased market demand for the whole plant (roots, leaves, and flowers) has prompted concern for the loss of native populations and potential loss in genetic diversity. Cultivation of echinacea can reduce or replace the need for a wildcrafted product, but field sowing is hindered by both low and uneven seed germination.

To solve this problem, dormancy breaking studies were conducted on freshly harvested seeds of Echinacea angustifolia. Seed lots were treated with tap water, 1 mmol ethephon (2-chloroethylphosphoric acid), 2,500 and 3,500 mg/l gibberellic acid, and combinations of these treatments, before transferring them to germination or stratification incubators. Seeds were stratified under light at 0°C and 10°C for 4, 8, and 12 weeks. An untreated seed lot was used as a control. Seed lots were placed under light at a constant temperature of 25°C and at alternate temperatures of 25/15°C for 14/10 h, respectively.

Germination was more rapid and uniform, and percent germination was higher at 25 °C than at 25/15 °C. Untreated seeds (control) at 25°C and 25/15°C resulted in 65 and 14% germination, respectively. Pre-soaking under tap water did not increase seed germination. Seed treatments by ethephon and GA resulted in ca. 90% germination with no stratification. There were minimal seed germination differences between 0 and 10 °C stratification. Germination percentage increased at both stratification and germination temperatures for seeds subjected to the prechill with water and soaking treatments as stratification duration increased from 4 to 12 weeks. Soaking+ethephon resulted in > 90% germination after 4 weeks of stratification, whereas the same germination rate was only achieved by soaking + GA after 8 weeks of stratification.

Approximately two-thirds of the biological diversity of the world is estimated to be in tropical zones, mainly in developing countries. Brazil contains around 60,000 species of flowering plants, distributed in five large locations: Amazon (30,000); Cerrados (10,000); Caatinga (4,000); Atlantic rainforest (15,000); and the subtropical forest (3,000). Optimistic estimations indicate that less than 5% of the Brazilian flora has been chemically or pharmacologically studied.

In the last years, serious efforts to collect and preserve the genetic variability of medicinal plants have been initiated. The National Center for Genetic Resources and Biotechnology - Cenargen, in collaboration with other centers of EMBRAPA (Brazilian Agricultural Research Corporation), has a program to establish genetic reserves and germplasm banks for medicinal and aromatic species. There are three basic research areas in this program including ethnobotanical studies, germplasm collection and characterization, and in situ conservation.

The most important species collected will be presented with supportive data including their description, medicinal uses, chemical constituents, and pharmacological activity. A current status of conservation for each species, germplasm availability, collecting and in situ conservation areas will be highlighted.

Some of these species include: Cephaelis ipecacuanha (ipecac), a source of the alkaloids emetine and cephaline; Pilocarpus microphyllus (jaborandi), the unique source of pilocarpine used in glaucoma treatment; Solanum mauritianum (cuvitinga), a potential source of solasodine, a raw material to the semi-synthesis of steroidal hormones; Dimorphandra mollis (faveiro), source of rutine; Maytenus ilicifolia (espinheira santa), anti-ulceric; and Phyllanthus niruri (quebra-pedra) used in hepatitis B treatment.

Borago officinalis is the major source of gamma-linolenic acid used in several medicinal applications. These include lowering blood pressure and cholesterol levels, and for various hormone-related conditions such as atopic eczema and premenstrual syndrome.

The objective of this study was to describe the flowering response by a model of environmental influence on the emergence-flowering stage with a Spanish white flower variety.

The model used only photoperiod effects without vernalization effects.

Eight sowing dates were used: 03/09/96, 08/10/96, 15/11/96, 27/12/96, 27/02/97, 17/04/97, 10/05/97, and 26/08/97 at Buenos Aires (34° 35' S, 58° 29' W).

Phenological observations at emergence and first flowering were made in a Randomized Complete Block design with three replications. The model used was:

TT = a + b P + c/P

where TT is thermal time in °C day, P photoperiod mean, and a, b, and c are the genotype-specific constants.

In previous experiments, we assumed that vernalization effects are null (Sorlino et al, AAIC Conference, 1997), but now we have included more sowing dates. The good fit of this model did not include the 15/12, 27/12, and 27/02 sowing dates (summer dates). On these dates, the vernalization effects were important and the model fall off. Nevertheless, it was a good tool for production sowing dates at the field.

Among four different Hypericum spp (Hypericum perforatum, H. maculatum, H. pulchrum and H. hirsutum) known to grow wild in Udmurtia, Russia, only Hypericum perforatum is officially registered in the Russian State pharmacopoeia for internal and external medicinal treatments. H. perforatum and H. maculatum are found frequently to grow side by side. Therefore, traditionally both species are collected for industrial processing. The objective of this study was to determine the variations or differences in the content of hypericin, tannins, and total extractive matter between H. perforatum and H. maculatum under various growing conditions and developmental stages of the plants.

In H. perforatum, the highest tannin content was measured during intensive vegetative growth just before the beginning of flower buds. However, the tannin content was significantly lower during the early (seedling stage) and late (after the onset of fruit capsules) developmental stages. The highest hypericin content was measured during massive bud formation and the onset of flowering (5-10 % flowering), whereas this level drastically decreased after full blooming of the plants. There was a significant correlation between tannin formation and the accumulation of hypericin. The total extractive matter was at the highest peak just before the bud formation and during intensive flowering periods. In H. maculatum, the total extractive matter was significantly higher than H. perforatum in all developmental stages. In contrast to H. perforatum, the highest tannin concentration in H. maculatum was measured during full blooming, whereas the highest hypericin content was measured during intensive vegetative growth (just before bud formation). This finding is the first in its character and represents an important economic and therapeutic application. In line with H. perforatum, we suggest including H. maculatum as an official herb for pharmaceutical and cosmetic processing.

Echinacea purpurea is among the most important and best selling native American medicinal plants that is used as a good source for animal and human immunostimulation. In recent years, there has been a growing interest from various countries in organically cultivated Echinacea for the preparation of various herbal medicines and food supplements. The aerial parts of E. purpurea containing flower heads are used in the form of expressed juice, hydroaclcoholic extract, alcoholic tincture, encapsulated powders or tea preparations. However, there is no published information on how growing conditions, plant and flower developmental stages would affect some of the biologically active components of E. purpurea flower heads.

The objective of this study was, therefore, to investigate the variations in the content of hydrophilic (coffeic acid derivatives, such as cichoric acid, chlorogenic acid, echinacoside), and lipophilic (alkamides and polyacetylenes) components of Echinacea flowers. The aerial parts of the plants were harvested and the flowers separated at four developmental stages (1st stage, 2nd stage, 3rd stage, and 4th stage). HPLC was used to determine the components. The highest content of cichoric acid was measured during the 1st flower development stage, whereas the highest concentration of isobutylamides was found at the 3rd stage with further development of the flowers. As the seeds attained their maturity to dryness, however, isobutylamide levels started to significantly decline.

Unlike traditionally cultivated food or forage crops, the knowledge of the cultural practices for many medicinal and aromatic plants is limited to a handful of institutions or none existent. Many medicinal plants are still collected from the wild. Low level of seed germination is among the most limiting factors that affect successful cultivation and processing. As part of our long-term biotechnological research program for many cultivated crops at the Soil Science Department of Moscow Agricultural Academy, we developed a natural plant conditioner, RIBAV, by directly isolating it from the plants.

The objective of this study was to determine the effects of natural plant conditioner RIBAV on seed germination and photochemical activity of medicinal and aromatic plants and the establishment of the seedlings under greenhouse and field conditions. RIBAV is a none-chemical (none-synthetic) natural product obtained through proprietary biotechnological method. Dried seeds of Chamomilla recutita, Echinacea angustifolia, E. purpurea, Baptisia tinctoria, Hypericum perforatum, Salvia triloba, Lomatium dissectum, and Rummex acetosella were pretreated for 1 min, 1 h, and 24 h with RIBAV at the concentration of 1%, 10%, and 20%. The application of RIBAV significantly affected the rate of germination. The highest germination rate for chamomile, echinacea and sheep sorrel was obtained at a concentration of 1% dipped in the liquid for a duration of 1 min. The highest germination rate for baptisia, lomatium, St. John’s wort, and sage was obtained at a 10% concentration for 1 min. The photochemical activity of chamomile and echinacea showed significant difference compared to the control variants.

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Canola (Brassica napus) is known to produce high levels of glucosinolates. As canola tissues die, these compounds are converted to isothiocyanates, which are toxic to many crop pests. We tested the ability of ‘Jupiter’ canola, purposefully killed by simulated mowing or glyphosate application, to inhibit green foxtail (Setaria viridis) and redroot pigweed (Amaranthus retroflexus) seed germination and seedling growth during establishment of ‘Glooscap’ strawberry (Fragaria americana) in two identical experiments.

Although mown canola had enough shoot material to cover the soil surface completely, it had little effect on weed growth compared with untreated weedy checks. In contrast, canola treated with glyphosate eliminated nearly all weeds from strawberries. In this treatment, glyphosate was applied before strawberry transplantation and weed seed germination. Thus, glyphosate had no direct effect on weed control. This same treatment also stunted strawberry plants somewhat, but the crop eventually overcame this initial suppression.

In conclusion, a glyphosate-treated canola mulch may be a new use for canola by providing a possible short-term replacement for soil fumigants, such as methyl bromide, during strawberry establishment.

Little information is available on the response of lesquerella grown under saline conditions. This study was conducted at the U. S. Salinity Laboratory, Riverside, CA to determine the response of the crop to sodium sulfate-dominated saline irrigation waters commonly encountered in drainage water reuse systems in the San Joaquin Valley of California.

Two-month-old seedlings were transplanted into 24 outdoor sand tanks with 72 plants per tank and irrigated with a complete nutrient solution. Eight salinity treatments were imposed two weeks after transplanting. Salts were added over a two-week period to avoid osmotic shock to the seedlings. Electrical conductivities of the irrigation waters (EC_iw) were 3, 6, 9, 12, 15, 18, 21, and 24 dS m^-1. Vegetative growth was monitored at three monthly intervals commencing 15 February 1998 by selecting two representative plants per tank to determine fresh and dry weight, height of the main axis, number of primary lateral branches, and leaf area.

Fitted salinity tolerance curves indicated increased tolerance with plant age. For six- month-old plants, the threshold soil water was 7.6 dS m^-1 with a 9% decrease in the vegetative yield per unit increase in salinity above the threshold. The salinity level that resulted in a 50% reduction in biomass production (C₅₀) was 12.8 dS m^-1. This is less tolerant than was previously reported for seed yields in field studies. Leaf area, number of branches, and axis height were all reduced by salinity. Ion concentrations in leaf and stem tissue were determined. Seed yield, seed oil content, and fatty acid profiles were measured. Growth was significantly reduced at EC_iw in excess of 6 dS m^-1 and the highest salinity level (24 dS m^-1) was lethal to most plants. The few survivors in the highest salinity treatment were rescued and grown in crossing blocks under nonsaline conditions.

A preliminary trial was conducted in greenhouse sand cultures to compare the response of lesquerella with isosmotic solutions of chloride- and sulfate-dominated salinities. The experimental design was two salinity types (chloride, sulfate), two salt levels (osmotic potential = -0.16 MPa; EC_iw @ 4.4 dS m^-1 and osmotic potential = -0.52 MPa; EC_iw @ 15.2 dS m^-1 ), and three replications. Seeds were planted in six rows per tank; seedlings were thinned to 25 per row. Plants were irrigated three times daily with low salinity water that contains all essential nutrient ions. High salinity stress was applied three weeks after seedling emergence. Growth parameters as well as shoot ion uptake and distribution were measured.

Sunflower is a crop that may be adapted to soil and environmental conditions that do not allow the cultivation of other plants. The sunflower oil has high concentration of polyunsaturated fatty acids and may be used as a fuel; in addition, the protein has a high biological (nutritive) value. México imports 90% of oil seeds from different countries. Better knowledge about the physiology of the plant will allow us to increase the yield and to help adapt it for different environments. This may improve sunflower production in México and reduce imports.

This work was undertaken to study the biomass production and grain and oil yields of four sunflower genotypes in northern México. The varieties studied were: SAN-3C developed at the UAAAN; Victoria, developed at Institute National de Investigations Forestales, Agricales y Peccaries (INIFAP); Cernianka and Iregi, two Russian varieties. The four genotypes were seeded in June at the experimental field at the University in six rows plots, 700 m long and 0.8m between rows, and plant spacing of 0.25 m. A randomized block design with four treatments and three repetitions was used. Three irrigations were applied at different times after seeding: 8 days (emerging stage), 12 days (vegetative stage), and 56 days (blooming start). The variables evaluated were: leaf area, plant height, dry weight, stem diameter, grain yield, oil and protein content, and yield. The results were analyzed by