Negash, Legesse (Professor)Dawit, Teshome2018-07-112023-11-092018-07-112023-11-092009-01http://etd.aau.edu.et/handle/123456789/8113Studies on the germination physiology of Hagenia abyssinica (Bruce) J.F.Gmel were conducted using various levels of germination stimulators or inhibitors. Nursery establishment and growth performance of the resulting germinants were examined using different mixtures of growth media. Seeds were treated using various dilutions of plant-derived aqueous smoke extracts (10, 20, 30, 40 and 50%), different concentrations of GA3 and KNO3 (10-3, 10-4, 10-5, 10-6 and 10-7 M) and double distilled water (control). The seeds were germinated under laboratory conditions at 40 μ mol m-2 s-1, and at 220 C. Also, leaf aqueous extracts of Eucalyptus globulus ssp globulus at 10, 20, 40, 80 and 100% relative concentrations were applied to determine their effects on H. abyssinica seed germination under laboratory conditions. Smoke extract at 40 %, GA3 at 10-4 M and KNO3 at 10-5 Key words/phrases: Allelopathy, Germination, H. abyssinica, Seed, Seedling survival. M showed higher germination percentage (86, 79.6 and 89.6%, respectively) compared to the control (72%); and the difference was significant at P ≤ 0.05. Increasing relative concentrations of leaf aqueous extracts of E. globulus ssp globulus inhibited seed germination and complete failure of seed germination was recorded at 80 and 100% relative concentrations. Growth media containing red soil, decomposed cow dung and sand in the ratio 4:3:2 (SoDSa1), 4:3:1 (SoDSa2), 4:1:3 (SoDSa3) and 2:1:1 (SoDSa4) (19.1 ± 1.35, 20.58 ± 0.62, 19.21 ± 1.5 and 21.9 ± 1.01 cm, respectively) resulted in significantly (P ≤ 0.05) better growth in height, compared to the control (red soil only) (16.24 ± 0.59). Dry weights of the seedlings grown in the potting treatments SoDSa1, SoDSa3, and SoDSa4 (4.63, 4.30 and 5.53 g) were significantly larger than the control (0.70 g). The MDW (mean dry weight) of the seedlings grown in SoDSa4 was larger compared to the control. From these investigations, it is concluded that pre-treating seeds of H. abyssinica with aqueous smoke extract and KNO3 provided better stimulatory effect for attaining maximum germination percentage. The results also indicate that the seedlings of H. abyssinica grew faster and reached planting size within 5 months in a soil mixtures containing red soil, decomposed cow dung and sand in the ratios 2:1:1 and 4:3:2. Key words/phrases: Allelopathy, Germination, H. abyssinica, Seed, Seedling survival.enAllelopathyGerminationH. abyssinica,SeedSeedlingsurvivalThesis