In recent years, there has been an explosion in the number of commercial plant tissue culture (TC) units in India. More than 25 such companies have production capacity of two to five million plants per annum. Almost all units are export oriented, but the target crops are the same. Indoor foliage plants dominate the export market. Micropropagation industry in India is providing major support to Indian agriculture in four crop groups: Fruits, ornamentals, spices, forestry/plantation crops. Banana is the largest selling TC fruit crop. TC papaya plants are now marketed for extraction and processing of papain. TC anthuriums, orchids, and gerberas have attained commercial importance. TC rose plants are used as pot plants. Nearly 500 ha are under TC cardamom cultivation in southern India recording 20% to 30% increase in yield. Vanilla cultivation is expected to increase from the existing 50 ha to more than 400 ha in the coming years using TC plants. Sugar companies have in-house units for micropropagation of sugarcane. There is demand for bamboo and eucalyptus for selective reforestation. The TC Industry is constrained by the non-availability of international varieties, high infrastructure and electricity costs, and lack of managers with commercial experience. A shake-up is imperative, during which many of the existing TC units may not survive the year 2000.
Donglin Zhang, Hongwen Huang, and Dongyan Hu*
Horticultural plants include fruit, vegetable, ornamental, turf, medicinal, beverage, spice, and other economic species. Although these plants originally derive from wild populations and play a vital role in our daily life, their importance on protecting biodiversity has not been addressed. With tremendous driving force of their monetary value, farmers, gardeners, breeders, and researchers have domesticated, selected, and bred many new horticultural crops, which ultimately increase biological diversity in cultivated plant communities. Both morphological and molecular data from 90 accessions of cultivated Cephalotaxus and 48 accessions of cultivated Chamaecyparis thyoides demonstrated their wide range of morphological differences and more than 43% of genetic dissimilarity coefficients. In US alone, one new cultivar of Loropetalum chinense var. rubrum was released to the nursery industry every year since the first plant was introduced from Wuhan Botanical Garden in 1983. Obviously, human activities rapidly accelerate evolutions. To preserve and reproduce new and rare taxa, regeneration of these plants is challenging. Rooting of Magnolia grandiflora stem cuttings, overcoming Cephalotaxus seed dormancy, experimenting Pinus strobus embryogenesis, and overwintering Stewartia cuttings should be applied for reproduction studies of unusual horticultural clones. For plants that could not be regenerated with today's propagation methods, their seeds, tissues, pollen, and embryos should be preserved as some USDA labs do for heirloom horticultural crops. In the future, with aid of advanced science and technology, we should be able to regenerate those plants from preserved materials and increase biological diversity.
Jerry J. Baron, Robert E. Holm, and J. Ray Frank
The pest management industry does not have adequate financial incentives to develop the required data to register pest management tools with government authorities on fruit, vegetables, herbs, spices, nursery crops, landscape plants, flowers, turfgrass, and other specialty crops. Growers of these crops, collectively called minor crops, need pest control tools to be able to sustain production. The Interregional Research Project Number Four (IR-4) was established in 1963 by the U.S. Department of Agriculture to assist growers of minor crops by providing a mechanism to allow growers of these crops to have access to safe and effective pest management tools. Working with research, industrial and extension personnel at the state land-grant institutions and researchers at USDA, Agricultural Research Service, IR-4 develops the appropriate data to support registration of insecticides, fungicides, herbicides and plant growth regulators. Many of the uses of plant growth regulators in current use were developed with oversight provided by IR-4. There are many promising new plant growth regulators and/or uses in the commercial development pipeline and it is anticipated that assistance from IR-4 will be needed to support registration of these new materials on minor crops.
Reddy R. Chinthakuntla, Frank Matta, Rao S. Mentreddy, Umesh Reddy, Padmavathi Nimmakayala, Daniel Peterson, and Om Prakash Vadhwa
Chilepepper (Capsicum spp.) is the third most important vegetable crop in the United States. The market value of chile peppers for spices and condiments exceeds $650 million per year. With a growing Hispanic population across the United States, the demand for high yielding, good quality cayenne pepper continues to increase. In order to fulfill this niche market, a study has been initiated to develop pepper varieties that combine high yield potential with superior agronomic traits, including insect and disease resistance, and fruit characteristics, using molecular marker assisted breeding/selection. In preliminary trials, several F1 generations were created through inter- and intra-specific crosses among 220 germplasm lines belonging to six Capsicumsp. in the greenhouse. Selected F1 progeny, parent lines, and selected accessions were planted in single-row field plots the following summer. The crossing success was higher within species than between. The genotypic variation was significant for all parameters examined. The average percent germination (81.1) of F1 progeny was 32% and 45% higher than that of the parent lines and selected accessions, respectively. The F1 progeny were shorter in height; more vigorous in growth, flowered early, and with fewer, but heavier, fruits per plant out-yielded the parent lines and accessions by 50% and 120%, respectively. The study showed a marked heterosis in F1 progeny compared to the parent lines and accessions. Microsatellite genotyping to estimate genetic diversity and validation of markers that are linked to various traits is in progress and will be discussed in the presentation.
J. Baral and P.W. Bosland
Domesticated chile (Capsicum annuum L. var. annuum) is a widely cultivated spice and vegetable crop. It originated in the Western Hemisphere, but spread rapidly throughout the globe after the voyage of Columbus. However, very little is known about the genetic diversity of chile in Asia and especially in Nepal. Thus, research was conducted to document morphological as well as molecular characterization of C. annuum var. annuum landraces collected from Nepal. Genetic diversity in C. annuum var. annuum landraces from Nepal was investigated using randomly amplified polymorphic DNA (RAPD) markers and compared with that of C. annuum var. annuum landraces from the center of diversity, Mexico. RAPD marker based cluster analysis of C. annuum var. annuum clearly separated each accession. All accessions of C. annuum var. annuum from Nepal grouped into a single cluster at a similarity index value of 0.80, whereas, accessions from Mexico grouped into eight different clusters at the same similarity level indicating greater genetic diversity in Mexican accessions. RAPD analysis indicated that the Nepalese chile population went through an additional evolutionary bottleneck or founder effect probably due to intercontinental migrations. Some Nepalese accessions had unique RAPD markers suggesting that additional sources of genetic variation are available in Nepalese germplasm.
Arthur D. Wall, Marisa M. Wall, and Joe N. Corgan
Onions (Allium cepa L.) with ≥18% bulb dry weight are dehydrated and used for spices and food ingredients. Bulb weight characteristics and water-soluble carbohydrates (WSC) of two commercial dehydrator cultivars, GS02 and GS04, and a breeding population, NM9335, were studied before and after maturity to observe phenotypic traits that may be useful for selection during breeding programs, and to study dehydrator onion carbohydrate physiology. At maturity, NM9335, GS02, and GS04 bulbs had 11.9 ± 0.33%, 18.6 ± 0.27%, and 19.4 ± 0.40% dry weight, respectively. Mature GS04 plants had 76.5 ± 0.01% of whole plant dry weight in bulbs, which is an extraordinarily high crop harvest index. NM9335 bulbs had higher fresh (hydrated) weight than bulbs of GS04 and GS02, but bulbs in all populations accumulated similar amounts of dry weight. Bulb percent dry weight before maturity did not indicate percent dry weight at maturity in the high-solids commercial onion cultivars. Bulb percent dry weight declined slightly after maturity in all populations. Glucose, fructose, and sucrose were relatively low, and fructans with degree of polymerization ≥6 were relatively high in GS04, but the converse was observed in NM9335. Relative amounts of GSO4 bulb fructan increased sequentially, in order of rank, from DP4 to DP6, but the converse was observed for NM9335.
Cedric A. Sims and Srinivasa R. Mentreddy
Basil (Ocimum sp.), belonging to the mint family, Lamiaceae (Labiatae), is a popular herb grown for the fresh market or for its dried aromatic leaves, which are used as a spice or in potpourris. In Asian countries, basil, particularly O. tenuiflorum, is better known as a medicinal plant species used for treating ailments ranging from colds to complex diseases such as cancers and diabetes. In the United States, however, it has a limited acceptance as a fresh-market herb. There is much potential for developing basil as a medicinal plant to cater to the growing herbal medicinal products industry. A field trial was therefore conducted to determine optimum date of planting basil in Alabama. Six-week-old seedlings were transplanted from the greenhouse into field plots arranged in a split-plot design with four replications. Planting dates at monthly intervals beginning in April were the main plots and three Ocimum accessions, Ames 23154, Ames 23155, and PI 288779 were sub-plot treatments. The accessions were compared for growth, leaf area development, light interception, canopy cover, and dry matter accumulation and partitioning pattern over planting dates. Ames 23154, with greater canopy cover (98.5%) and photosynthetically active radiation interception (96.1%), also produced higher total plant biomass than other accessions. Accession PI 288779 appeared to partition greater dry matter to leaves, which are the primary source of bioactive compounds in basil. Among planting dates, second (May) date of planting appeared to be optimum for both total biomass and leaf dry matter production. Genotypic variation f or dry-matter partitioning and relationships among agronomic parameters as influenced by planting date will be discussed in this presentation.
Adel A. Kader
Postharvest losses of horticultural perishables between the production and retail distribution sites are estimated to range from 2% to 23%, depending on the commodity, with an overall average of about 12% of what is shipped from U.S. production areas to domestic and export markets. Estimates of postharvest losses in developing countries are two to three times the U.S. estimates. Losses in dried grains, legumes, nuts, fruits, vegetables, and herbs and spices range from 1% to 10%, depending on their moisture content, temperature and relative humidity of transport and storage facilities, and protection against pathogens and insects. Reduction of these losses can increase food availability to the growing population, decrease the area needed for production, and conserve natural resources. Strategies for loss prevention include use of genotypes that have longer postharvest-life, use of an integrated crop management system that results in good keeping quality of the commodity, and use of the proper postharvest handling system that maintains quality and safety of the products. Biological (internal) causes of deterioration include respiration rate, ethylene production and action, rates of compositional changes, mechanical injuries, water loss, sprouting, physiological disorders, and pathological breakdown. The rate of biological deterioration depends on several environmental (external) factors, including temperature, relative humidity, air velocity, and concentrations of carbon dioxide, ethylene, and oxygen. Socioeconomic factors that contribute to postharvest losses include governmental regulations and policies, inadequate marketing and transportation systems, unavailability of needed tools and equipment, lack of information, and poor maintenance of facilities. Although minimizing postharvest losses of already produced food is more sustainable than increasing production to compensate for these losses, less than 5% of the funding of agricultural research is allocated to postharvest research areas. This situation must be changed to increase the role of postharvest loss reduction in meeting world food needs.
Donald N. Maynard
specific underutilized crops, including six fruits, five vegetables, one root and tuber crop, two flowers, three trees, and two spices. Thus, there is something for horticulturists of every persuasion. One chapter is dedicated to the underutilized fruits
Mary Ann D. Maquilan, Dominick C. Padilla, Donald W. Dickson, and Bala Rathinasabapathi
Bell and chili peppers are important vegetable and spice commodities worldwide. Significant yield reductions have been attributed to damage caused by root-knot nematodes (RKNs; Meloidogyne spp.). This study addresses the need for developing pepper varieties that have high resistance to RKN, which is now of increasing importance due to restrictions on the use of fumigant nematicides. Our goal is to provide a nonchemical alternative to sustain commercial pepper production in Florida, which is a major producer of peppers in the United States. We evaluated ‘UFRJ107(6)A3’, an advanced inbred line developed from a cross between Capsicum annuum L. ‘Jalapeno’ and ‘Round of Hungary’, for resistance against the nematode in comparison with the parental and three other Capsicum cultivars, namely, C. annuum ‘Charleston Belle’, ‘California Wonder’, and C. chinense Jacq. ‘Datil’ in two separate growth chamber experiments. Based on egg mass indices and reproduction factors, ‘UFRJ107(6)A3’ was significantly more resistant to M. incognita compared with the other five cultivars. When tested with five RKN species, ‘UFRJ107(6)A3’ showed comparably high levels of resistance to M. arenaria and M. floridensis as ‘California Wonder’ based on the nematode reproduction factor. In ‘UFRJ107(6)A3’, however, there were no detectable M. arenaria egg masses, and M. incognita reproduction was minimal compared with that of ‘California Wonder’; both cultivars supported the reproduction of M. enterolobii and M. javanica, although the reproduction factors of M. enterolobii were ≈10-fold higher than M. javanica. To characterize the mechanism of high resistance to M. incognita in ‘UFRJ107(6)A3’, we examined the extent to which infective second-stage juveniles (J2s) were able to penetrate its roots in comparison with the susceptible ‘California Wonder’ and ‘Datil’ in two independent experiments; we conducted RKN root penetration assays with a single plant in a pot and two plants in a single-pot choice test using ‘Datil’ and ‘California Wonder’, respectively, as susceptible standards. In both assays, M. incognita J2s were absent in the roots of ‘UFRJ107(6)A3’ 7 days after inoculation but were present in the susceptible cultivars, indicating that resistance has an effect at the root invasion stage. In growth chamber experiments, at constant temperatures of 28 and 30 °C, ‘UFRJ107(6)A3’ exhibited M. incognita resistance superior to its parents and to the standard resistant bell pepper ‘Charleston Belle’, thus offering the potential to enhance specialty pepper production and for use as a nematode-resistant rootstock for commercial bell peppers.