This study aimed to determine the effect of dolomite and lighting duration on the generative characteristic performance of alfalfa plants. The experiment was conducted at Greenhouse of Forage and Pasture Science Laboratory, Faculty of Animal Sciences, Universitas Gadjah Mada, from May to September 2015. This study is designed with randomized complete block design (RCBD) factorial pattern of 3 × 3 with four replications. The first factor was the dose of dolomite (D) with three treatments (D0, without dolomite; D1, dolomite 90 g/plant or 6 t/ha; and D2, dolomite 180 g/plant or 12 t/ha). The second factor was the long lighting duration (C) with three treatments (C0, 12 h of lighting; C1, 14 h of lighting; and C2, 16 h of lighting). The parameters measured were the time of flowering, time of podding, the number of flowering plants, the number of podded plant, the number of pods per plant, seed weight per plant, and seed alfalfa viability test. The results showed that the treatment of lighting duration significantly affected (p < 0.05) the number of flowering plants, the number of podded plant, the number of pods per plant, and seed weight per plant alfalfa. Dolomite dose treatment significantly affected (p < 0.05) the number of pods per plant and seed weight per plant alfalfa. There was an interaction between lighting duration and dosage of dolomite that significantly affected the number of pods per alfalfa plant.
