Research on cassava crop (Manihot esculenta   Crantz.) in Eastern Venezuela

From the results of the diagnosis of cassava crop development in the savannas of Eastern Venezuela by the realization of 44 research works from 1962 to 1998, it was found that from interpretation of physiologic function of the carbohydrates accumulation in the roots and from the selection of adapted cultivars to the savanna conditions, the best genotypes were for bitter type, the clone José María and among sweet type, the clone Mantequilla. Vegetative material of basal origin should be used which promotes a production of 21.5 t/ha and the cultural practices that lead to this yield were: use of 45 cm-cuttings, sowed in May with a spacing of 0.8 m between rows and 0.5 m between plants, making the weed control with herbicide Cotoran in doses of 2 to 3 kg/ha and fertilizing with 90 kg of nitrogen, 114 kg of phosphorus and 80 kg of potassium per hectare. In relation to the deterioration of cassava roots, it was found that when the pruning of stalks is carried out, fifteen days before root harvesting, this allowed roots remain up to twelve days without brown spotted. Seven researches were carried out about agro-social-economic aspects of cassava and it was found that when a technological package was applied (new varieties sowing, fertilization, weed control with herbicides, insecticide use, etc.), the production of cassava roots was tripled