ISHS Acta Horticulturae 380: Symposium on Tropical Root Crops in a Developping Economy
GENOTYPE EVALUATION FOR INTERCROPPING SYSTEMS |
| Authors: | D.S.O. Osiru, H.C. Ezumah |
| Abstract:
Research aimed at improving the productivity of intercropping systems is often difficult because of the many constraints to be tackled. However, among the researchable issues, identification of suitable varieties is probably the most urgent priority for research. During the past five years, the research agenda at IITA has emphasized the improvement of intercropping systems involving cassava through genotype evaluation. This paper discusses the experimental procedure and some aspects of the results obtained. Two approaches were adopted. The first examined the compatibility of five maize genotypes of contrasting growth characteristics together with IITA's improved cassava variety, TMS 30572. The results showed that maize genotypes which produced high yield in monoculture, yielded almost similarly when intercropped with cassava. However, the effects of maize on the performance of the associated cassava crop varied considerably with the growth habits of maize because cassava was the dominated crop. The tall spreading maize substantially reduced cassava root yield whereas the short spreading vegetative maize reduced cassava root yield only slightly. The second approach examined the performance of a wide range of cassava genotypes under monoculture or intercropped with either maize or groundnuts. The results showed that intercropping cassava with maize or groundnuts decreased root yield of cassava but the extent of the reduction varied much with genotype and the component species (relative yields ranged from 0.49 to 0.98), suggesting that the relative competitive abilities of cassava were greatly influenced by its genotype. However, the ranking order did not differ markedly between cropping systems. The varieties which yielded high in monocrop situation also yielded consistently high when intercropped with both maize and groundnuts. The coefficient of determination was high (R2 = 0.82; R2 = 0.78, respectively for cassava/groundnuts and cassava/maize), indicating a very close positive correlation between intercropped and monocropped yield of cassava. The overall implications of these results in the selection of appropriate genotypes for intercropping systems are discussed. | |
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