Like many cities in the world, the city of Abidjan has experienced, in recent years, a significant development of market gardening. At the same time, the popularization of urban agriculture is controversial in terms of food security given the exposure of crops to pollutants, including trace elements, generated by agricultural practices and urban activities. In this work, we have compared, by a principal components analysis, the potential for the accumulation of five trace metals, cadmium, copper, lead, zinc and nickel, by three market garden species, lettuce, spinach and amaranth. The market garden species came from two market gardening sites, Marcory and Cocody, and the experimental plot of Nangui Abrogoua University. The results showed that lettuce has a greater capacity for accumulation of the five metals than for spinach and amaranth. However, amaranth and spinach from the three sites showed almost the same metal accumulation capacity.

One of the major challenges of agriculture in the African countries is food self-sufficiency. Within this framework, Vigna unguiculata or African bean plays a significant role. However, the level of productivity of this culture in these regions in the process of development is low. The agromorphologic characterization of niébé could make it possible to optimize the programmes of traditional selection of the more productive accessions. The objective of this study of is identified the most powerful accession being able to answer the new conditions related to the climatic changes. The study related to 16 accessions, the agro-morphological variability was evaluated on the basis of 8 parameters. The results showed that varieties N21DR, N18ZR, N10BBrp tested during the present study present an aptitude to be produced simultaneously in quantity and quality of seeds in a relatively short cycle of culture. The analysis in principal component (ACP) of the quantitative variables revealed of the very powerful accessions (cycle runs, a number of pods raised by plant, grains large and heavy) like which one can use in the programs of selection.