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Givago Coutinho, Rafael Pio, Filipe Bittencourt Machado de Souza, Daniela da Hora Farias, Adriano Teodoro Bruzi, and Paulo Henrique Sales Guimarães

studies on the agronomic performance of quince cultivars cultivated in the tropics, especially in humid subtropical climates, which hiders the selection of cultivars with superior agronomic characteristics and the use of this fruit in regions with a mild

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Peter Juroszek and Hsing-Hua Tsai

costs and groundwater pollution, without decreasing fruit yield. It is beyond the scope of this study to discuss topics such as availability of high-quality seed, seed cost, and marketing opportunities of organically grown vegetables in the tropics

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Michael J. Willett, Lisa Neven, and Charles E. Miller

'deshova (1967) present the hypothesis that the confirmed distribution of CM is roughly limited by a combination of short daylengths in the tropics (that would continuously induce diapause in the larvae) along with the lack of chilling temperatures to release CM

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J. Farias-Larios, S. Guzman-Gonzalez, and A. Michel-Rosales

The productivity of marginal soils frequently found in the arid tropics might be improved by using VAM fungi as “biofertilizer” and as a tool of sustainable agricultural systems. Study of mycorrhizas of fruit trees was performed in 1987 in western Mexico. More progress has been made in resources, taxonomy, anatomy and morphology, physiology, ecology, effects, and application of mycorrhizas in fruit trees and ornamental plants production. Currently, five genera has been identified and inoculated plants showed significant difference in respect to plants not inoculated with mycorrhizal fungi. Citrus trees were highly dependent on mycorrhizae for normal growth and development, while the banana plants showed lower levels of root colonization by different strains of VAM fungi. The added endomycorrhizal inoculum significantly increased root fungal colonization in fruit trees and reduce the time in nursery. The current status and research trends in the study of fruit tree mycorrhizas in western Mexico are introduced, and the application prospects in sustainable agriculture also are discussed.

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Mari Marutani, Joseph Tuquero, Robert Schlub, and James McConnell

The effects of a vesicular–arbuscular mycorrhizal fungus, Glomus aggregatum inoculation were examined on growth of vegetable crops in pot culture and field experiments with Guam cobbly clay loam soil (clayey, gibbsitic, nonacid, isohyperthermic Lithic Ustorthents). In pot experiments, the growth response of yard-long beans (Vigna unguiculata subs. sesquipendalis), sweet corn (Zea mays), watermelon (Citrullus lanatus), cucumber (Cucumis sativus), okra (Abelmoschus esculentus), green onion (Allium fistulosum), eggplant (Solanum melongena), and papaya (Carica papaya) were significantly improved with mycorrhizal inoculation. A pot experiment was also conducted to evaluate effects of G. aggregatum inoculation on the growth of corn seedlings at four different water regimes. Seedlings inoculated with G. aggregatum significantly improved the plant growth and the mineral uptake at all levels of water treatments. In the first field trial, prior to seed sowing the media in seedling trays were either inoculated or not inoculated with G. aggregatum. Treated watermelon and eggplant seedlings were transplanted in field. It was found that inoculating seedlings did not improve the harvest yield of two fruit-bearing crops. The second field experiment was conducted to study G. aggregatum inoculation and different levels of inorganic fertilizer application on growth of corn. Mycorrhizal colonization had positive effects on corn development and uptake of some minerals such as Fe. Experiments in the study suggested potential uses of a mycorrhizal fungus in an alkaline soil in the tropics.

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Joseph K. Njuguna*, Leonard S. Wamocho, and Teddy E. Morelock

Temperate zone fruit crops undergo bud dormancy which can be described as a mechanism for avoiding the exposure of tender flowers and leaves to low winter temperatures. In Kenya, apple growing is mostly hampered by inadequate chilling that causes the plants to have prolonged dormancy leading to poor flowering and consequently low yield. Although the chilling requirements are obligatory, under subtropical and especially tropical conditions avoidance is possible. To achieve this, it is necessary to select cultivars with low chilling requirements. This has proven effective in Zimbabwe with cultivar Matsu which is grown without a need for artificial breaking of dormancy. In Kenya like Zimbabwe, low chilling requiring cultivars such as Anna have been grown successfully. However, for cultivars with high chilling requirements, there is need to apply artificial techniques/methods to enhance bud break. Some of the cultural techniques used are: defoliation after harvesting and bending of the shoots holizontally. Defoliation after harvesting has particularly been used successfully in the island of Java in Indonesia and it enables two crops to be grown per year. Root chilling of rootstock has also been found to enhance bud break of the shoot. In addition, chemicals like KNO3, mineral oil and thiourea (TU) have been found to be effective in breaking bud dormancy in Kenya. This paper is reviewing the challenges encountered in growing apples in the tropics and Kenya in particular and the progress that has made in addressing them.

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Fernando Ramírez, Thomas L. Davenport, Gerhard Fischer, and Julio Cesar Augusto Pinzón

-Elisea, 1997 ; Núñez-Elisea et al., 1996 ). In contrast, reproductive flushes generally occur after extended periods of stem rest in constantly warm temperatures of the low-latitude tropics ( Bueno and Valmayor, 1974 ; Davenport, 2009 ; Davenport and Núñez

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Manuel C. Palada, Thomas J. Kalb, and Thomas A. Lumpkin

AVRDC–The World Vegetable Center was established in 1971 as a not-for-profit international agricultural research institute whose mission is to reduce malnutrition and poverty among the poor through vegetable research and development. Over the past 30 years, AVRDC has developed a vast array of international public goods. The Center plays an essential role in bringing international and interdisciplinary teams together to develop technologies, empower farmers, and address major vegetable-related issues in the developing world. In its unique role, AVRDC functions as a catalyst to 1) build international and interdisciplinary coalitions that engage in vegetable and nutrition issues; 2) generate and disseminate improved germplasm and technologies that address economic and nutritional needs of the poor; 3) collect, characterize, and conserve vegetable germplasm resources for worldwide use; and 4) provide globally accessible, user-friendly, science-based, appropriate technology. In enhancing and promoting vegetable production and consumption in developing world, AVRDC's research programs contribute to increased productivity of the vegetable sector, equity in economic development in favor of rural and urban poor, healthy and more diversified diets for low-income families, environmentally friendly and safe production of vegetables, and improved sustainability of cropping systems. Recent achievements at AVRDC that greatly impact tropical horticulture in the developing world include virus-resistant tomatoes raising farmers income, hybrid sweet pepper breaking the yield barrier in the tropics, flood-resistant chili peppers opening new market opportunities, broccoli varieties for monsoon season, pesticide-free eggplant and leafy vegetable production systems and fertilizer systems that protect the environment. Beyond vegetable crops, AVRDC is playing an important role in expanding and promoting research and development efforts for high value horticultural crops, including fruit, ornamentals, and medicinal plants through its new Global Horticulture Initiative. AVRDC believes that horticulture crop production provides jobs and is an engine for economic growth. The important role AVRDC–The World Vegetable Center plays in developing and promoting tropical horticultural crops is discussed in this paper.

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Mary Lamberts

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J. Benton Storey

Tropical horticultural crops can be the spark that builds student interest in horticulture. They are a refreshing alternative to the temperate crops that most of our curricula are necessarily built around. Students who become familiar with production problems and opportunities between 30° north and south latitudes are better equipped to compete in the world economy. HORT 423 covers tropical ecology, soils, atmosphere, and many major crops. Beverage crops studied are cacao, coffee, and tea. Fruit and nut crops include bananas, mango, papaya, pineapple, dates, oil palm, coconut, macadamia, cashew, and Brazil nuts. Spices such as vanilla, black pepper, allspice, nutmeg, mace, cinnamon, cassia, and cloves are studied. Subsistence crops such as cassava, yam, taro, pigeon peas, chick peas, vegetable soy beans, and black beans round out an exciting semester that draws students. HORT 423 is a 3-hour-per-week lecture demonstration course supplemented with slides from the tropical countries. Many students simultaneously enroll in a 1-hour HORT 400 course that is taught during the 1-week spring break in a tropical country. Recent trips have been two each to Costa Rica and Guatemala. These study trips are gaining in popularity. For more information about HORT 423 consult the world wide web at http://http.tamu.edu:8000/~c963/a/h423main.html.