Biomass production and forage quality of head-smut disease resistant Napier grass accessions
Napier grass, commonly known as “elephant grass”, is a major feed used for dairy production by smallholder farmers in eastern and central Africa. However, the productivity of the grass in the region is threatened by stunt and head-smut diseases. The objective of this study was to determine biomass yield and forage quality of headsmut resistant/tolerant Napier grass accessions, in the high and lowland environments of Kenya. A field study was undertaken at two contrasting environments. The first site was in the highlands at KALRO-Muguga (altitude 2,052 metres above sea level), while the second site was in the lowlands at KALRO-Katumani (altitude 1,600 metres above sea level). The study was initiated in November 2011 using canes to plant ten Napier grass accessions (ILRI numbers 16790, 16791, 16783, 18448, 16806, 16808, 16809, 16796, 16835, 16837) in separate 4 m x 4 m plots. The grasses were first harvested at 23 week after planting at both sites. Subsequent harvests occurred at intervals of eight weeks after regeneration. There were eight growth cycles from 1st November 2011 to 9th May 2013 at each site. There were differences (P<0.05) between accessions in forage dry matter production that ranged from 28.8-51.2 metric tonnes ha-1 at KALRO-Muguga and 18.1-26.7 metric tonnes ha-1 at KALROKatumani. The accessions (numbers 16783, 16796, 16806 and 16835) resistant to head-smut disease gave dry matter yields comparable to that of accession number 16791 which was the negative check. There were differences (P<0.05) between the accessions in neutral detergent fibre at both sites. There were differences (P<0.05) in nitrogen content (mean 2.6%) at KALRO-Muguga. Accession no. 16806 was confirmed resistant to head-smut disease, while accession nos. 16783, 16796 and 16835 were tolerant to head-smut disease in glasshouse screening/ molecular studies.
Key Words: Kenya, Pennisetum purpureum, rain use efficiency