Summary Several genotypes among the interspecific F1 hybrids between Maiwa, a short-day, photoperiod-sensitive local cultivar of pearl millet (Pennisetum americanum [L.] Leeke), and elephant grass (P. purpureum Schumach) produced at the University of Ibadan, Nigeria, combine the high dry-matter yield potential and perenniality of elephant grass with greater acceptability to livestock and increased digestibility, resulting in higher live-weight gains than elephant grass. Though sterile, the F1 Pennisetum hybrids are easily propagated vegetatively. Distribution over a wider area of adaptation can be facilitated by large-scale F1 seed production utilizing cytoplasmic male-sterile pearl millet. Cytoplasmic male-sterile Maiwa was developed by transferring male-sterility factors from Tift 23A pearl millet, using a backcrossing procedure. Male-sterile Maiwa was grown between rows of 6 elephant grass ecotypes that combine well with Maiwa. To ensure coincidence of flowering with elephant grass, Maiwa was sown at the end of August. Seed-head diseases, the most serious being ergot (Claviceps sp.), resulted in heavy losses; 3.17 kg of F1 hybrid seed was recovered from a 358 m2 plot. This is equivalent to a production of 88.5 kg/ha of hybrid seed, adequate to establish 8 ha of pasture when the seed is sown at the rate of 11 kg/ha in rows 90 cm apart. At Ibadan, under ideal conditions, a 1.60-ha multiplication nursery is required to establish the same acreage vegetatively. The study has shown that large-scale production of the F1 Pennisetum hybrid seed is practical. A much higher seed yield can be expected if diseases prevalent in the humid environment of Ibadan can be contained. Seed production in less humid regions where pearl millet is normally cultivated should minimize the problem.