Selection Efficiency in Musa L. Under Different Cropping Systems (Report‪)‬

Introduction Plantains and bananas (Musa spp.) are perennially cultivated in compound gardens or backyard soils, which are rich in organic matter and nutrients from the household refuse, either as pure stands or mixed with other crops in small fields. These gardens can be permanently cultivated for several decades with plants growing vigorously, giving an annual yield of about 3050 tones per hectare (Nweke et al. 1988). Compound gardens cannot however, be readily extended, hence large-scale production will only be achieved through cultivation in field plantations under monoculture regimes. In this case, obstacles to increasing production include rapid yield decline after 1-2 years due to loss of soil organic matter and reduction in soil fertility (Ayodele 1986). This is aggravated by the fact that subsistence agriculture in tropical Africa is characterized by production in marginal areas with great environmental variability. It is further compounded by farmers' lack of technological and economic resources to modify their environments to fit the needs of the crops. An improved system for large-scale production of plantains and bananas through alley cropping, which is dependent on managing the soil in a way that fertility is maintained, is advocated (Owoeye, 1996). Alley cropping is an agroforestry technology, which involves the cultivation of food crops between hedgerows of multipurpose trees or shrubs. It incorporates the desirable features of bush fallow into a continuously productive farming system. Crop yield is improved through enhanced nutrient recycling; organic residues from hedgerow pruning (Owoeye, 1996), and increased nitrogen availability through biological N fixation (Kang et al. 1984). The mulch also suppresses weeds, protects the soil during intense rainfall and conserves soil moisture during the drier periods. Perennial production of plantains can therefore be achieved in forest fields, when cultivation is done between rows of a multiple-species complex. Alley cropping system may be adopted as an alternative to large-scale production of plantain and banana (Musa spp) under monoculture regimes. The Musa breeder is, however, faced with the challenge of selecting varieties that will give satisfactory yield, and will not display substantial trait variations over cropping systems. Regardless of the cropping system adopted, selection of individual plants or families is made to increase genetic gain within and across generations.