Description

A poster presented at the 2012 Global Pulse Researchers Meeting, Kigali, Rwanda- “Transforming Grain-Legume Systems to Enhance Nutrition and Livelihoods”. Abstract: Climbing beans (Phaseolus vulgaris L.) are commonly intercropped with maize (Zea mays L.) on subsistent agricultural landscapes, but little research has been done on genotype by cropping systems interactions under farmer conditions. In plant breeding programs, beans are selected under monoculture. We studied the effect of genotype by cropping systems interactions using a mother-baby-grandbaby field model in which replications were planted on eight farmer associations’ fields in five locations and at two research stations in Rwanda, to determine if beans varieties selected in monoculture perform equally well in an intercrop with maize. Five climbing bean genotypes and one local mixture of beans were grown in an intercrop with maize and in a monocrop. At the end of each of two seasons, farmers selected their preferred varieties for each cropping system using participatory variety selection techniques developed in Rwanda. Results indicate that most farmers choose different bean varieties for different cropping systems, and the variety choice varies across locations. Farmers did not always identify specific traits exclusive to bean varieties suitable for intercropping. At the end of the first season, 70 farmers selected their preferred varieties for each system and planted them on-farm in their own “grandbaby” plots, enabling them to experiment with the varieties and adjust the mother-baby protocol to suit their farm conditions. Ongoing interviews and field visits to farmers’ plots demonstrate further their bean variety preferences, if there are specific bean variety traits associated with a cropping system, and how they experiment with varieties. Preliminary findings indicate that genetic diversity in bean varieties is critical in the heterogeneous environments characteristic of small-scale farming. This research documented many niches; farmers valued different varieties for each. Plant breeding and agronomic research needs to take into account the surprisingly wide range of varieties that were valued depending on the site, and on the cropping system. This research has implications for expanding the numbers of varieties bred, and released to small farmers in Rwanda.