Local cultivars of many crops have been cultivated under marginal environments with little care for improved agronomic management practices. The productivity is often half of the potential but the qualities of such local cultivars ensure their local adaptation to the various biotic and abiotic factors of production. However, genetic erosion of local cultivars has increased through the diffusion of modern and high-yielding varieties. Improved varieties have high yield potential and yield is the important decisive variable in crop production. The lower productivity of local cultivars is one of the factors triggering the loss of traditional varieties and crop species. The following case study illustrates how farmers evaluate technologies while adopting them, even if only incremental yield advantage is associated with the technique.