INTERACTIONS OF Capsicum annuum L IN MONOCULTURE AND IN INTERCROPPING WITH Setaria verticillata (L.) P. BEAUVOIS.
Mixture is a system of two or more different plant species interacting with each other in different manners. Interspecific competition, resource complementarity and facilitation may modulate better performance of a mixture. It is difficult to interpret the results of a simple mixture experiment, if the phenomena act together. An experimental design is used to study interactions between chilies or peppers, Capsicum annuum L. var. ‘Baklouti’ and Setaria verticillata (L.) P. BEAUVOIS. A replacement series design was used to compare C. annuum/ S.verticillata interactions under monocultures vs. polycultures. The experiment is conducted in the greenhouse of the Higher Institute of Agricultural Sciences, of Chott-Mariem, 4041, University of Sousse, Institution of Agricultural Research and Higher Education (IRESA), Ministry of Agriculture and Water Resources, Tunisia during 2011-2012 crop season. In this replacement experiment, C. annuum and S. verticillata seedlings were transplanted into pots with different proportions of both species (0/6, 1/5, 2/4, 3/3, 4/2, 5/1, 6/0). Dry weights of two species were measured at the harvest time at 40 days age from transplantation. The relative interaction index, relative competition intensity and actual dry weight loss was calculated for both species. These intercropping evaluation indices showed that C. annuum is a weak competitor and S. verticillata is a strong competitor. The dry weight advantage was caused by the rapid growth of S. verticillata. C. annuum cannot grow with S. verticillata due to very competitive nature of this weed. The suppression of the later weed is unavoidable for growth of C. annum. Further studies are suggested confirm the present findings.