characterization of the ideal bean (phaseo1us vu1garis L.) genotype for intercropping

Abstract

Some 73 hybrid populations of beans (Phaseolus vulgaris L.) were raised at Thika. Commencing at F2, P3 or BC1, the seed from each population was divided into two portions. In /subsequent segregating generations, eacll portion of seed was advanced and selection repeatedly done in either monoculture beans or beans intercropped with maize at two locations in Kenya. In order to characterise the ideal be~n genotype for intercropping,. studies were conducted on the resultant bean genotype groups having selection histories either in monoculture or under intercrcpping with maize. The performances of genotype groups were compared with respect to yield, yield components and developmental plant characteristics. Genotype by cropping system interactions for these characters and yield correlations between monoculture and intercropped beans were addressed. When inter cropped with maize, bean genotypes selected under intercropping gave higher grain yield than those selected in monoculture. Low correlation coefficients between monoculture and beans inter-. cropped with maize were obtained. - XII - The study indicated the· early enhancement of the reproductive phase and~short maturity duration as adaptive features-of the bean to the inter-cropping environment. Adaptive architectural characteristics of an ideal inter-cropping bean genotype include a short plant stature with high amount of branching.