Search Results
Prior to the 20th century, the American chestnut, native to the Appalachian region, was highly valued for its timber and sweet nuts. The introduction of chestnut blight, ca. 1900, has destroyed the species economically, but enough germplasm survives to resurrect the species, if blight can be overcome. Most research in the USA has focused on chestnut blight, neglecting other problems and opportunities, especially commercial production of exotic chestnut species. A large commercial industry does not yet exist in the USA, but does in other parts of the world. Blight-resistant exotic species could be cultivated as a highvalue crop adapted to well-drained, acidic soils. In contrast to other nuts, chestnut kernels are low in fat and high in carbohydrate giving them unique culinary and food processing uses. Current problems are cultivar selection, propagation, insect pests, postharvest quality, and marketing.
Abstract
Chinese chestnut (Castanea mollissima Bl.) has much potential as a nut-producing orchard or landscape tree, being resistant to chestnut blight [Endothia parasitica (Murr.) P.J. & H.W. Anderson] and high-yielding. Chestnut is monoecious and largely self-sterile, requiring cross-pollination to produce nuts (Sanders, 1974). There is considerable variation in nut traits, such as size and sugar content, even among nuts from the same tree (Miller, 1987), due to, in part, xenia effects. The nut is composed mostly of cotyledonary tissue with a small embryo and no endosperm (Sanders, 1974). Propagation by seed is generally successful; however, no criteria exist for selection of nuts that will produce superior seedlings. The objectives of this study were to examine the relationships between seed weight, seedling emergence, and seedling growth of half-sib Chinese chestnut seeds.
Abstract
Variation in peroxidases due to age and locus in the plant greatly exceeded variation due to growth habit genotype in cucumber (Cucumis sativusL.).
Abstract
The inheritance of reduced vine size was studied in 2 dwarf lines of cucumber (Cucumis sativus L.) derived from Hardin's PG-57. The dwarfs were crossed with 3 standard cultivars and 3 determinate breeding lines and found to carry a recessive determinate gene, allelic with gene de. There was evidence for the existence of another recessive gene, dl (delayed growth) which reduced the length of the hypocotyl and the first few internodes, and reduced growth rate; dl appeared weakly linked with de. The presence of genetic modifiers of determinate habit make it feasible to breed determinate cucumbers over a wide range of final vine sizes.
Trees of `Redhaven' peach [Prunus persica (L.) Batsch] budded to Lovell, Bailey and Nemaguard rootstocks were grown with either bahiagrass or cultivated row-middles. Terminal shoots and roots were collected on four dates during 1991-92 (Nov. 15, Jan. 16, Feb. 26 and Apr. 1). On the April 1 collection date, trees grown with cultivated row-middles had higher levels of total soluble sugars and total carbohydrates in shoot tissue than trees grown with sod. There were no differences on any of the other dates. Orchard floor management did not affect the levels of Ca, Mg, K, P or Fe in shoots or roots. Trees on Nemaguard rootstock had significantly less starch and total carbohydrates in shoot tissue than those on Lovell on the last two collection dates. Shoot tissue of trees on Nemaguard and Bailey rootstocks had lower levels of K than those on Lovell. Sorbitol and total soluble sugar levels were higher in the root tissue of Lovell than Bailey and Nemaguard. Nemaguard had significantly higher levels of starch in root tissue than Lovell and Bailey. Nemaguard and Bailey had lower levels of Mg in roof tissue than Lovell.
The major markets for cowpea are seed sales and processing. During the storage period prior to sales, some seedcoats of `Mississippi Silver' darken from tan to varying shades of brown. This darkening is undesirable for the processing market, since it results in an unattractive product lacking uniformity. A series of studies was undertaken to investigate this problem. It was noted that darkening proceeded at a rapid rate when seed were left in the field after drying. Selection against darkening was unsuccessful, and attempts at extracting the colored compound with polar and nonpolar solvents were inconclusive. A method of screening for the darkening trait was devised. It was found that darkening could be induced by exposing seed to a high-oxygen environment, suggesting that oxidation is involved in the darkening process. In support of this, it was found that the lowest rate of darkening occurred when the seed were placed in an enriched nitrogen chamber after harvest.
The Chinese chestnut (Castanea mollissima Blume) and other Castanea species (Castanea spp. Mill.) have been imported and circulated among growers and scientists in the United States for more than a century. Initially, importations of C. mollissima after 1914 were motivated by efforts to restore the American chestnut [Castanea dentata (Marsh.) Borkh.], with interests in timber-type characters and chestnut blight resistance. Chestnut for orchard nut production spun off from these early works. Starting in the early 20th century, open-pollinated seeds from seedlings of Chinese chestnut and other Castanea species were distributed widely to interested growers throughout much of the eastern United States to plant and evaluate. Germplasm curation and sharing increased quite robustly through grower networks over the 20th century and continues today. More than 100 cultivars have been named in the United States, although a smaller subset remains relevant for commercial production and breeding. The University of Missouri Center for Agroforestry curates and maintains a repository of more than 60 cultivars, and open-pollinated seed from this collection has been provided to growers since 2008. Currently, more than 1000 farms cultivate seedlings or grafted trees of the cultivars in this collection, and interest in participatory on-farm research is high. Here, we report descriptions of 57 of the collection’s cultivars as a comprehensive, readily accessible resource to support continued participatory research.
Researchers have collected a considerable amount of data relating to apple (Malus ×domestica) cultivars and rootstocks over the past 30 years, but much of this information is not easily accessible. The long-term goal of our working group is to increase access to this information using online technology available through eXtension. In eXtension, researchers and extension personnel are developing a community of practice (CoP) to increase the quality and amount of online information for individuals interested in our work [referred to as a community of interest (CoI)]. For this project, our CoI is broadly defined as commercial apple producers, nursery professionals, county extension educators, Extension Master Gardeners, home gardeners, and consumers. Our CoP is developing diverse educational tools, with the goals of increasing productivity, profitability, and sustainability for commercial apple production. Additionally, we will provide other members of our CoI access to research-based, reliable information on the culture of apples. We chose to begin our focus on cultivars and rootstocks adapted to the eastern United States and will add other U.S. regions as our resources and interest in our project grows.