Abstract
The role of horticulture in meeting world food requirements is a positive one; horticultural crops do have a unique place in meeting world nutritional needs. I feel fortunate in this assignment of topics because I think that the most important role of fruits and vegetables is in providing vitamins A and C in our diets.
Feeding intensity of adult Japanese beetle (Popillia japonica Newm.) was compared among 27 taxa of Prunus host plants during 24-hour no-choice feeding trials conducted on individual leaves. Fecal dry mass per beetle, a measure of feeding intensity, varied from 0 mg·d-1 for Prunus padus L. to 20.4 mg·d-1 for P. sargentii Rehd. and P. tomentosa Thunb. Prunus padus, P. laurocerasus L., P. mahaleb L., P. serotina Ehrh., P. virginiana L., P. americana Marsh., P. ×yedoensis Matsum., and P. besseyi Bailey were resistant based on feeding intensities of <4.3 mg·d-1 (levels not significantly different from zero). Feeding intensity decreased exponentially as endogenous foliar cyanide potential increased. Evaluation of the cyanogenic glucoside prunasin in artificial diets showed a similar relationship with feeding being reduced by 50% (ED50) at 4.9 mmol·kg-1 in the diet. Prunus mahaleb was highly resistant to Japanese beetles despite having low cyanide potential. Two coumarin compounds known to exist in P. mahaleb, herniarin and coumarin, were tested in artificial diets and were effective feeding deterrents with ED50 values of 5.9 and 2.5 mmol·kg-1 in the diet, respectively. This research demonstrated a wide range of host plant resistance to feeding by adult Japanese beetles and further indicates that prunasin, herniarin, and coumarin are important factors in host plant resistance to this pest.
Abstract
Potatoes (Solanum tuberosum L.) normally are propagated vegetatively by tubers and produce a uniform, productive, high-quality crop. However, tubers accumulate systemic diseases, which greatly reduce their productivity and quality. Many countries control these diseases with complex and expensive seed certification programs. Such control methods are not available in many other countries where potatoes are an important part of the diet.
Vegetarianism dates back to a time before recorded history and, as many anthropologists believe, most early humans ate primarily plant foods, being more gatherers than hunters. Human diets may be adopted for a variety of reasons, including political, esthetic, moral, environmental and economic concerns, religious beliefs, and a desire to consume a more healthy diet. A major factor influencing the vegetarianism movement in the present time is primarily associated with better health. Epidemiologic data support the association between high intake of vegetables and fruit and low risk of chronic diseases and provide evidence to the profound and long-term health benefits of a primarily vegetarian diet. Vegetables and fruit are rich sources of nutrients, vitamins, minerals, and dietary fiber as well as biologically active nonnutrient compounds that have a complementary and often multiple mechanisms of actions, including antioxidant, anti-inflammatory, hypoglycemic, hypocholesterolemic, and hypolipidemic properties, and mechanisms that stimulate the human immune system. Because of the critical link established between diet and health, consumers have begun to view food as a means of self-care for health promotion and disease prevention. Functional foods are targeted to address specific health concerns, such as high cholesterol or high blood sugar levels, to obtain a desired health benefit. Functional properties identified in a number of plant species have led to a modern day renaissance for the vegetarian movement.
Every 5 years, the U.S. Department of Agriculture (USDA) releases dietary guidelines to help Americans choose nutritious foods to prevent chronic, diet-related diseases and promote better health. Nutrient-rich vegetables are a critical part of this
Resin glycosides extracted from sweetpotato skins were bioassayed for their effects on survival, development, and fecundity of diamondback moths, Plutella xylostella (L.). Glycosides were incorporated into an artificial diet (Bio-Serv, Inc.) and fed to diamondback larvae. Neonatals were individually fed artificial diet with 0.00, 0.25, 0.50, 1.00, 1.50, and 2.00 mg·mL-1. There were highly significant negative correlations between glycoside levels and survival as well as weight of survivors after 6 days. A significant positive relationship existed between dosages and development time. Lifetime fecundity was negatively affected at sublethal doses. The glycosides are viewed as contributors to resistance to the wireworm, Diabrotica and Systena insect complex.
Abstract
Carotenes from vegetables and fruits are vitamin A precursors that contribute about half of the vitamin A in the U.S. diet (3) and two-thirds of the world diet (5). Carrots typically contain 65 to 90 ppm carotenes (1) and are estimated to be the major source of carotene for U.S. consumers (3). Few pro-vitamin A sources surpass the carotene content of typical carrots, although red palm oil can contain >825 ppm carotenes (2). Genetic selection for higher carotene levels in carrots could increase the dietary consumption of carotene and consequently vitamin A. A high carotene mass carrot population was developed for use in breeding, genetic, and biochemical studies of carrot (Fig. 1).
This article examines the nutritional quality and human health benefits of melons, specifically, muskmelon or cantaloupe (Cucumis melo L. var. reticulatus Naud.) and honeydew melon (Cucumis melo L. var. inodorus Naud.) types. Melons are naturally low in fat and sodium, have no cholesterol, and provide many essential nutrients such as potassium, in addition to being a rich source of beta-carotene and vitamin C. Although melons are an excellent source of some nutrients, they are low in others, like vitamin E, folic acid, iron, and calcium. Since the U.S. diet is already high in fat and protein content, melons should be included in everyone's diet, along with five to eight servings per day of a variety of other fruit and vegetables, to ensure adequate nutrition, promote individual health, and reduce one's risk of cancer and certain other chronic diseases.
Abstract
It is tempting to overemphasize the role of horticultural crops in man's diet. Horticultural crops rank a poor second after the cereal grains as an energy source (Table 1) (5). It is clear that roots and tubers, fruits, nuts and vegetables contribute less than a third of the dietary calories supplied by the cereal grains. There are several factors which deserve consideration in interpreting these data.
Abstract
Multiple cropping systems are characterized by high plant species diversity, closed cycling of nutrients, reduced pest incidence, erosion control, low but stable yields, and an intensive exploitation of limited land resources. Used on small farms in Latin America for centuries, bean-maize systems provide a source of income and a balanced diet for the farm family. Limited technology has reached this sector of the agricultural population, and new research reveals an impressive potential for improving yields in the bean-maize cropping system.