Evaluation of New Cassava Varieties for Compatibility with Maize and Cowpea under Intercropping

Intercropping is a production system that involves the growing of two or more crops simultaneously on the same piece of land. In intercropping, the component species are not necessarily sown at the same time and their harvest times may be different, but they are simultaneous for a significant part of their growing period. Past research at KALRO-Mtwapa developed cassava varieties that are high yielding and tolerant to cassava diseases. The varieties were developed and tested under sole cropping but farmers intercrop cassava with maize and cowpea. An experiment was therefore conducted at KALRO-Mtwapa to evaluate the new cassava varieties for their suitability for intercropping with maize and cowpea. Four cassava varieties: KME-08-05 (Karembo), KME-08-02 (Tajirika), KME-08-06 (Nzalauka) and clone 2855 were used. The treatments comprised of the varieties and their intercrops with either maize or cowpea. The cassava number of root per plant was significantly (p ≤ 0.05) influenced by the presence of either maize or cowpea intercrop for all varieties except Karembo when intercropped with maize. Cowpea significantly (p ≤ 0.05) reduced the number of roots per plant for Karembo and Tajirika but its effect on clone 2855 and Nzalauka was similar to that of maize for the same parameter. Among the crop treatments clone 2855 had significantly lower number of roots per plant than the other three clones. In terms of root yield Karembo recorded significantly (p ≤ 0.05) higher yield than Tajirika and clone 2855. However its root yield was significantly (p ≤ 0.05) reduced by both maize and cowpea intercrops. The yield reduction by cowpea was significantly (p ≤ 0.05) higher than that of maize. The root yield for the Nzalauka and 2855 was significantly reduced by the presence of cowpea intercrop. Tajirika showed significantly (p ≤ 0.05) higher net income under cowpea intercrop than the other varieties. The yields of both maize and cowpea when intercropped with the four cassava varieties did not reveal any significant difference implying that cassava had no effect on the performance of the intercrops. Maize is therefore a better candidate for intercropping with cassava than cowpea and Tajirika is the most suitable variety for intercropping in coastal lowland Kenya.