Early Harvesting of Cassava Grown under Rainfed Conditions

Abstract

The performance of eight cassava clones was compared using four planting dates (May 1983, January, Auguse and November 1984) and two harvest times (8 and 12 months). The study was done under rainfed conditions in the dryland tropical climate of Rayong province in Eastern Thailand on a soil typical of those used for cassava cultivation. Total harvestable yield continued to increase when the growing period was extended from 8 to 12 months; the yield increase per day was similar for cassava harvested at 8 months as 12 months. The potential for january, May and Movember sowing for harvesting at 8 months was demonstrated, with a potential tuber yield of 8.75 ton ha-1 dry weight or 25 ton ha-1 fresh weight. The yield from harvesting at 8 months varied from 65% to 95% of that from harvesting after 12 months, the magnitude of the difference dependent on seasonal growing conditions. Clones which gave good yields from harvesting at 8 months also gave good yields when harvestedat 12 months. A yield improvement of up to 30% over the best traditional cultivar, Rayong 1, appears to be possible through genetic selection.