the fact that the bulk of productivity enhancements achieved in ldcs have come from increased yields rather than from labour productivity points to the importance of technology embodied in higheryielding varieties or in superior species of cattle which can improve the wellbeing of farmers technology directly influences not only variety yields but also the adaptation of plant and animal varieties to local agroecological conditions the quality of inputs seeds fertilizers machinery the choice of cultivation and rearing techniques etc producers capacity to learn and adapt to new technologies and circumstances is partly determined by the quality of their human capital the importance of agricultural rd is highlighted by the fact that the modest recovery in productivity gains in subsaharan africa in the s has been attributed to increased spending on agricultural rd and extension services as well as improved price incentives fuglie and rada block