In spite of its rapid growth in recent years, the floricultural industry in Korea is rather small with respect to total acreage and number of growers engaged, product value, international trade, and production facilities and technics involved. The production status will be introduced with slides. Nevertheless, variable climatic conditions of the temperate zone such as the distinctive 4 seasons favor the prosperous growth of a variety of vegetation throughout the Korean peninsular. Thus, it has been wellknown that many ornamental plants native to Korea have good potentials for horticultural use. The morphological characteristics of a few selected plants will be introduced along with slides. These plants include Aster spp, Iris spp, Gentiana soabra, Chrysanthemum zawadski, Pulsatilla koreana, Cymbidium spp, Calanthe spp, Dendrobium moniliforme, Abeliophyllum distichum, Ardisia spp, Hibiscus syriacus, and many others.
Jong-Suk Lee and Ki-Sun Kim
Laura C. Merrick, Frank Drummond, Constance Stubbs, and Rhonda Weber
Managed and feral honey bee (Apis mellifera) colonies have declined dramatically in the past decade due largely to parasitic mites, pesticide contamination, and severe weather. Squash (Cucurbita spp.) is one of many agricultural crops whose production may be negatively effected by decline of these pollinators. A study was conducted on a set of nine farms in Maine to assess the relationship between bee abundance and fruit set of summer and winter squash. The organic and conventional farms targeted in the study included farms with and without the presence of honey bees. With winter squash, fields with more bees tended to exhibit higher fruit set. The average fruit set was slightly higher for farms with honey bees (42%) vs. those without (35%), but both types of farms were similar to that found in controlled hand pollinations (31% on average). In contrast, fruit set for summer squash averaged 95% to 96% for all farms, regardless of the relative abundance of censused bees. Bumble bees (Bombus spp.) were the most abundant wild bees found pollinating squash. Farms with honey bees on average had higher numbers of bees in squash flowers than farms without honey bees, although a difference in preference for floral sex type was detected for bee taxa. Honey bees were much more likely to be found in female flowers, while bumble bees were more abundant in male flowers. Significantly more native bees were found in squash flowers on farms without honey bee hives, although native bees were still present to some extent on farms that were dominated by Apis mellifera.
Alan W. McKeown, John W. Potter, Mary Gartshore, and Peter Carson
Root lesion nematodes (Pratylenchus penetrans Cobb) are well-adapted to sandy soils and have a host range including most agronomic, horticultural, and wild species grown in Ontario. As native climax sand-prairie species have coexisted with the nematode for millennia, resistance or tolerance may have developed. We have screened using the Baermann pan technique, soil samples taken from a private collection of sand-prairie species collected from local prairie remnants. Several species [Liatris cylindracea Michx., Monarda punctata L., Pycnanthemum virginianum L., Echinacea purpurea (L.) Moench] proved to be excellent hosts (>500/kg of soil) of root lesion nematode, confirming the presence of this nematode in the soil. Over two seasons, we determined that 10 plant species belonging to the families Asclepiadaceae, Compositae, Graminae, and Leguminosae to support very low numbers of P. penetrans. Brown-eyed susan (Rudbeckia hirta L.) had no root lesion nematodes throughout both seasons, Butterfly weed (Asclepias tuberosa L.) very low counts, while Switch grass (Panicum virgatum L.) and Indian grass [Sorghastrum nutans (L.) Nash] had detectable root lesion nematodes on only one sampling date each year. Big Bluestem (Andropogon gerardii Vitman), Little Bluestem [Schizachyrium scoparium (Michx) Nash], Sand Dropseed [Sporobolus cryptandrus (Torr.) Gray], Side-oats Grama [Bouteloua curtipendula (Michx.)) Torr], Broomsedge (Andropogon virginicus L.), Bush clover [Lespedeza capitata (Michx] also are poor hosts. These species have potential as cover or rotation crops useful for nematode management.
Masud A. Khan and James N. McCrimmon
The multiple use of water from aquaculture to supplement irrigated crop production could minimize the cost of growing fish and irrigating crops. Aquaculture effluent was utilized to supplement the fertility and irrigation of six native shrub species (big sage, fourwing saltbush, mountain mahogany, Mormon tea, rubber rabbitbrush, and winterfat). Plants were established in two container types: 20-liter standard polypot and nonwoven UV-stabilized Duon synthetic fiber growbags. The plants were irrigated with fish effluent or city water. Plants irrigated with fish effluent were not given any fertilizer treatment, while plants irrigated with city water were fertilized with Osmocote®. Fish effluent was suitable for production of fourwing saltbush, rubber rabbitbrush, big sage, and winterfat. Fourwing saltbush irrigated with effluent had the best survival rate, while mountain mahogany irrigated with effluent had the poorest growth and survival rates. Big sage, rubber rabbitbrush, and winterfat had better growth and survival rates in the growbags, while Mormon tea had better growth and survival rate in the polypot containers.
James H. Fownes, Robin A. Harrington, and Darrell A. Herbert
Two studies were established in upland native forest of northwestern Kauai before Hurricane Iniki (Sept. 1992). One study was a gradient study in Acacia koa forest in the leeward rain shadow and the second study was a replicated fertilization experiment in mesic Metrosideros polymorpha forest. Both studies escaped devastation by high-intensity microbursts. Removal of LAI (from 3% to 80%) was proportional to pre-hurricane LAI, suggesting that resistance to damage was higher in low LAI, low-productivity sites. LAI recovered to prehurricane levels within 2 years, except in plots with major limb and stem loss. In the Acacia forest, damage to overstory trees was less than to understory trees, whereas in Metrosideros forest, larger trees were more damaged than smaller trees. During 2 years of recovery, both forests lost LAI in winter storms nearly equivalent to the hurricane damage. Disturbance is more frequent than previously known, which suggests that chronic disturbance needs to be better understood as a force regulating ecosystem structure and function. In both studies, the relative rate of recovery was faster in the more productive but more disturbed plots, suggesting that ecosystem resistance and resilience were traded off. These results have application to land use planning, agroforestry systems management, and other perennial crop management decisions following damage by a tropical cyclone.
S.A. Balch, C.B. McKenney, and D.L. Auld
The oil of evening primrose (Oenothera sp.) is an important source of gammalinolenic acid (GLA). GLA [C18:3Δ6,9,12] is an unsaturated fatty acid in demand for its nutritional and pharmaceutical application. Oenothera biennis L. is the primary commercial source of evening primrose oil. A study was conducted to determine if species of Oenothera, adapted to Texas, produce GLA levels comparable to O. biennis. This project identified and evaluated the fatty acid composition of eight species of evening primrose native to Texas. GLA levels of 54 accessions evaluated from collected seed ranged from 0.0% to 11.0%. Field experiments were then conducted to determine oil content, fatty acid composition, seed yield, and potential adaptation to commercial production of selected accessions. Mean GLA levels of cultivated seed from these accessions ranged from 0.0% to 10.1%. Mean seed oil content ranged from 7.3% to 21.7%. Of the species examined, O. elata subsp. hirsutissima (A. Gray ex S. Watson) W. Dietrich and O. jamesii (Torrey & Gray) demonstrated GLA levels and seed yields adequate for commercial production. Based on these results, O. elata subsp. hirsutissima and O. jamesii demonstrated sufficiently high GLA levels, oil content, and seed yields to be considered for commercial production.
Kyoung-Shim Cho, Hyun-Ju Kim, Jae-Ho Lee, Jung-Hoon Kang, and Young-Sang Lee
Fatty acid is known as a physiologically active compound, and its composition in rice may affect human health in countries where rice is the major diet. The fatty acid composition in brown rice of 120 Korean native cultivars was determined by one-step extraction/methylation method and GC. The average composition of 9 detectable fatty acids in tested rice cultivars were as followings: myristic acid; 0.6%, palmitic acid; 21.2%, stearic acid; 1.8%, oleic acid; 36.5%, linoleic acid; 36.3%, linolenic acid; 1.7%, arachidic acid; 0.5%, behenic acid; 0.4%, and lignoceric acid; 0.9%. Major fatty acids were palmitic, oleic and linoleic acid, which composed around 94%. The rice cultivar with the highest linolenic acid was cv. Jonajo (2.1%), and cvs. Pochoenjangmebye and Sandudo showed the highest composition of palmitic (23.4%) and oleic acid (44.8%), respectively. Cultivar Pochuenjangmebye exhitibed the highest composition of saturated fatty acid (28.1%), while cvs. Sandudo and Modo showed the highest mono-unsaturated (44.8%) and poly-unsaturated (42.4%) fatty acid composition, respectively. The oleic acid showed negative correlation with palmitic and linoleic acid, while positive correlation between behenic and lignoceric acids was observed.
Fifty nine morphological characters and isozyme band patterns of glutamate oxaloacetate transminase, peroxidase, glucose phosphate isomerase from fully expanded leaves were used for taxonomic study on 51 taxa consisted of Korean native and principal cultivars of the genus Pyrus. Taxonomic relationships were analyzed by complete cluster analysis method based on Euclidean taxonomic distance of IBM PC SPSS/PC+(ver. 3.0). Among the 39 qualitative morphological characters, a great deal of variations among 51 taxa were observed in immature fruit shape, skin lusterness, hair density on pedicel, anther color, shape of leaf apex and base, hair density on leaf surface, and leaf margin. Considerable variations were found in most tested quantitative characters except in the number of petals and styles. More reliable taxonomic results could be obtained by comparing morphological characters rather than examining isozyme band patterns. Even though there were considerable differences depending upon the methods of investigation, classification of the genus Pyrus by using isozyme band patterns was proved to be a good tool for rapid taxonomic studies.
Charleson R Poovaiah, Stephen C Weller, and Matthew A Jenks
An in vitro shoot regeneration procedure was developed for native spearmint (Mentha spicata L.) using internodal explants. Shoot regeneration from internodes was evaluated on Murashige and Skoog (MS) media supplemented with individual cytokinins thidiazuron (TDZ), benzylaminopurine (BA), kinetin (KT), or zeatin (ZT) or various pair wise combinations of these. The highest regeneration was achieved by the second internode on a medium containing MS basal salts, B5 vitamins, 10% coconut water, 1.0 mg·L–1 TDZ, 2.5 mg·L–1 ZT, and solidified with 0.2% phytagel. Unlike previous protocols this medium does not need sub culturing and produces elongated shoots in 4 weeks, rather than 6 weeks. Maximum number of shoots (36 per explant after 4 weeks) was observed when internodes from 2-week-old stock plants were used as explant source. The shoots were removed and roots were initiated on medium containing MS basal salts, 0.4 mg·L–1 thiamine-HCL, 100 mg·L–1 myo-inositol, 7.5 g·L–1 agar and 0.01 mg·L–1 ∝-napthaleneacetic acid (NAA) and then plants were transferred to the greenhouse 2 weeks after root initiation, where 100% of the plantlets developed into healthy plants.
Julia L. Bohnen and Anne M. Hanchek
The Legislative Commission on Minnesota's Resources funded a two year research project to promote expansion of the native wildflower and grass seed industry in Minnesota. Production of seeds and plants for landscaping and restoration is a growing sector of the horticultural industry, yet documentation of production techniques is sketchy due in part to the large number of species. The species Lilium philadelphicum (wood lily), Phlox pilosa (prairie phlox), and Spartina pectinata (prairie cordgrass) were selected for further analysis of germination requirements. These species were noted by producers as having poor and/or unreliable germination. Cold moist stratification and gibberellic acid (GA) treatments were applied Total percent germination and mean days to germination were calculated and analyzed after 30 days under greenhouse growing conditions. Stratification improved total percent and mean days to germination in L. philadelphicum. P. pilosa responded to treatment by both stratification and GA. Four weeks of stratification may be the best method for decreasing mean days to germination while obtaining adequate total percent germination for S. pectinata.