STUDIES OF TIGER NUT AND SWEET POTATO - INTERACTION AS INFLUENCING GROWTH AND YIELD OF THE COMPANION CROPS *

Orange fleshed sweet potato and tiger-nut are tuber crops that have numerous food and nutritional benefits; they are, therefore, staple foods in every home in Nigeria. However, farmers in south-eastern Nigeria still marginally accept the cultivation of these crops. The study objective was to investigate plant-to-plant interaction as influencing growth and yield of three varieties of orange-fleshed sweet potato and tiger-nut. The experiment was conducted in a research field of Department of Crop Science, University of Nigeria, Nsukka in a 3×3 factorial combination laid in a completely randomized design with five replicates. The orange-fleshed sweet potato genotypes and tiger-nut were planted either as sole crops and or intercropped with one or two tiger-nut plants. The results showed that the sole system produced high yield of orange-fleshed sweet potato and tiger-nut tubers. Umuspo 3 recorded the highest root yield in this investigation, while two plants of tiger-nut recorded higher yield but in retrospect, one plant of tiger-nut was more productive. Umuspo 1 also exhibited strong allelopathic tendencies where it suppressed the growth and yield of tiger-nut and there was no weed incidence throughout the growth stages. Two tiger-nut plants intercropped with Umuspo 4 exhibited higher growth and yield parameters. Evidences of growth and yield depression by the intercrop supported the hypothesis of existence of allelopathic effects from both crops. Implication is that the two crops should not be planted together or in close proximity.