Yield and Productivity of Eggplant Genotypes Intercropped with Vegetable Cowpea in the Humid Tropics

Abstract

ABSTRACTIntercropping fruit vegetable crops with legumes may influence performance of component crops and improve residual nitrogen contribution to the cropping system. Eggplant (Solanum spp.) genotypes whose fruit and leaves are a good source of income and provide essential vitamins and minerals for good health were intercropped with vegetable Cowpea (Vigna unguiculata Walp ssp. sesquipedalis) in 2 years. Eggplant was monocropped using genotypes ‘Ex-Lantan’, Solanum macrocarpon L., S. melogena L, S. aethiopicum L. (mikky mikky-Gilo), ‘Nsukka green’, and ‘Nsukka white’. A semiprostrate vegetable cowpea was grown in monocrop and the crops were intercropped. Eggplant fruit yield, pod yield of cowpea, and interrelationships between yield characters, as well as the biological and economic productivity of the system, were studied. Intercropping eggplant with cowpea produced a high degree of complementarity. The mono- and intercropped eggplant genotypes exhibited wide genotypic variation. On average over two cropping seasons, ‘Nsukka green’/cowpea intercrop followed by ‘Nsukka white’/cowpea intercrop had the highest total land equivalent ratio (LER; 1.78) and land equivalent coefficient (0.79) compared to other mixes. The ‘Ex-Lantan’/cowpea intercrop had the highest mean gross monetary and net returns (NR); the S. melogena/cowpea intercrop produced the highest total cost of production (TCP) among intercrops; the highest benefit–cost ratio (BCR) was for monocropped S. macrocarpon. Among intercrops, the BCR of S. macrocarpon/cowpea mix was highest compared to ‘Ex-Lantan’, S. melongena, S. aethiopicum, ‘Nsukka green’, and ‘Nsukka white’, at 0.57%, 21.58%, 33.46%, 26.30%, and 19.89%, respectively. There was a positive but weak linear relationship between LER and NR and between LER and BCR. Intercropping eggplant with cowpea enhances productivity and financial return.