Effect of Harvesting Times after Stem Cutting on Yield and Starch of 4 Cassava (Manihot esculenta Crantz) Ciltivars in Red-Brown Clayey Loam Soil in Lopburi Province

Abstract

The effects of cassava stem cutting at 10 and 12 months after planting (MAP) on fresh root yield and starch content in each harvesting time after stem cutting for 18 MAP. Four cassava cultivars namely: CMR 35-21-199, Rayong 7, Rayong 9 and Rayong 11 were planted in May,2008 on red-brown clayey loam soil Lopburi Agricultural Research and Development Centre, Lopburi province. It was found that the fresh root yields of stem cutting at 10 and 12 MAP in CMR 35-21-199, Rayong 7 and Rayong 9 were not significantly different, while Rayong 11 produced the highest starch content. The results of stem cutting in both periods showed that the harvesting at 2 months after stem cutting. However, all experiments showed the highest fresh root yields and starch contents when harvesting at 17 months. Furthermore, stem cutting at 10 MAP and harvesting at 7 MAC has fresh root yields and starch content higher than stem cutting at 12 MAP and harvesting at 5 MAC, and 17 months of non-cutting. Additionally, during 8-18 MAP, fresh root yields was increased according to the age of cassava, and starch content in fresh root showed the highest value at 8 months (harvested in December). While starch content showed the lowest content at age of 11 months (harvested in March) probably due to the period time of forming new leaves. After that, starch contents were increased again and subsequently decreased at 18 MAP.