Effect of Cassava(Manihot esculenta crantz) Stake orientation and Planting depth on planting material multiplication ratio and tuberous root yield

Abstract

Cassava (Manihot esculenta Crantz) is a tuber crop grown widely in Zambia by small scale farmers as a staple carbohydrate. The crop offers many advantages but its potential has been fully exploited. This failure has been in part due to poor production practices and the lack of improved planting materials. The crop is grown from stem cuttings of various lengths that are planted horizontally, vertically or at an incline at various planting depths. This does not favor the production of adequate planting material within a short time compared to other crops. Furthermore, this will affect its tuber yield. Therefore, the objective of this study was, to determine the effects of planting depth and stake orientation on planting material multiplication ratio and tuberous root yield of cassava. Two varieties of cassava; Bangweulu and L9.304/151 were used in the study. Stem cuttings, 30 cm long, were planted at depths of 5 cm, 10 cm and 15 cm and 20 cm in horizontal (0o), vertical (90o) or inclined position (45o). A split-split plot design with four replications was used in the study. Varieties were in the main plots, while planting depths were the sub plots and stem orientations the sub-sub plots. Within the plots, the spacing was 1 m inter-row, and 1 m in the intra-row. Data collected included number of stems/planting station, plant height, number of tuber/plant, and tuber weight/ha. The results obtained revealed that the two varieties gave similar multiplication rates of 1:4 to 1:6. Planting the stakes vertically or at an incline gave more stems per station (2.0) than planting horizontally (1.5) and these gave higher planting material multiplication rates (1:6) horizontally planted ones (1:4). In addition, these plants gave more tubers per plant (6 tubers/ plant) than those planted horizontally (tubers/plant). Significantly higher tuber weights (10.5t/ha to 9.4t/ha) were obtained from vertically and inclined sown plants than horizontally ones (5.9t/ha). However, highest tuber yield (12.8t/ha) for Bangweulu was obtained when stakes were planted vertically but for L9.304/151 (8.0 to 10.6t/ha) when planted either vertically or on the incline. This study showed that the crop can be planted at depths of 5 cm to 20cmwithout affecting its production of planting material and tuberous root yield but these stakes should be planted either vertically or inclined to obtain higher planting material multiplication rates and tuberous root yields.