Abstract:
Five alfalfa genotypes were evaluated for herbage yield potential and nutritional quality under supplemental irrigation condition at Holetta Agricultural Research Center during 2010-2014. The experiment was conducted in randomized complete block design with four replications. Diammonium phosphate (DAP) fertilizer at the rate of 100 kg/ha was uniformly applied at sowing. Combined analysis revealed that the tested genotypes varied significantly (P<0.05) for dry matter yield and plant height at forage harvesting. Accordingly, the highest mean dry matter yield was recorded for Hairy Peruvian (8.7 t/ha) followed by FG-10-09(F) (6.3 t/ha), Magna 801-FG (F) (6.2 t/ha), Magna 788 (5.6 t/ha) and FG-9-09 (F) (5.5 t/ha) genotypes. Similarly, Hairy Peruvian, FG-10-09 (F), Magna 801 FG (F), Magna 788 and FG-9-09(F) genotypes produced 77.7, 60.1, 55.6, 53.3 and 52.7cm plant height at forage harvesting respectively. Hairy Peruvian gave the highest crude protein yield (1.7 t/ha) and digestible yield (6.5 t/ha) followed by FG-10-09(F) genotype, which produced 1.4 t/ha and 4.8 t/ha crude protein yield and digestible yield respectively. On the other hand, the lowest crude protein yield (1.2 t/ha) and digestible yield (4.0 t/ha) was recorded for FG-9-09(F) genotype. The highest relative feed value was recorded for Magna 788 (143.5% DM) genotype followed by FG-9- 09(F) (137.6%DM), FG-10-09(F) (134.6%DM), Magna 801-FG(F) (132.9% DM) and Hairy
Peruvian (122.3% DM) genotypes. Except in-vitro dry matter digestibility (IVDMD), the tested genotypes did not show significant (P>0.05) difference for all measured herbage quality traits. The result showed that Magna 801-FG (F) genotype had the highest ash (115.0 g/kg DM), IVDMD (757.7 g/kg DM) and hemicellulose (104.5 g/kg DM) contents. On the other hand, FG-9-09(F) genotype had the lowest NDF (416.9 g/kg DM), ADL (86.1g/kg DM), and hemicellulose (65.2g/kg DM) contents. The highest CP (226.6 g/kg DM) and the lowest ADF (319.9 g/kg DM) and cellulose (229.4 g/kg DM) contents were recorded for Magna 788 genotype. Similarly, the highest NDF (454.6 g/kg DM), ADF (376.6 g/kg DM), ADL (103.7 g/kg DM) and cellulose (279.0 g/kg DM) contents and the lowest ash (102.6 g/kg DM) and CP (199.2 g/kg DM) contents were recorded for Hairy Peruvian. Generally, alfalfa genotypes showed variations in terms of biomass yield potential and nutritional quality under supplemental irrigation condition at Holetta, in the central highland of Ethiopia.