Negash, Legesse (Professor)Alebachew, Kassahun2020-11-172023-11-092020-11-172023-11-092018-09-09http://etd.aau.edu.et/handle/123456789/23334The present study was undertaken to address two major challenges in Dodonaea viscosa Jacq subsp. angustifolia (L.f) Benth, namely to break seed coat dormancy and to assess the potential of early survival and growth performances of seedlings in soils sampled from degraded landscapes. D. viscosa subsp. angustifolia is an ecologically and medicinally very significant indigenous shrub or small tree, which belongs to the family Sapindaceae. It is a multi-seeder, evergreen, drought resistance, fast growing and pioneer plant that can grow in poor soils. However, to use the plant in restoration programs its complete, rapid and uniform germination is limited by species’ seed coat dormancy. The present study attempted to break seed dormancy through mechanical scarification, treatment with 98% sulphuric acid for 1, 3, 5, 10, 20 and 30 minutes, also hot water treatments at 70, 80, 90 and 95C for 5, 10, 20, 30 and 40 minutes for each of the specified temperatures employed with a view to breaking seed dormancy of the species. Non-scarified seeds were used as a control. To determine the extent of early seedling survival and growth performances, a total of 120 seedlings of D. viscosa subsp. angustifolia were grown in soils sampled from degraded landscapes. The experiment was conducted under nursery bed conditions, and the results were compared with those obtained from plants grown in soils mixed with 50% compost. The study found that all scarification treatments improved mean germination percentage and rate. Mechanical scarification and acid treatments for 10, 20, and 30 minutes significantly increased (p ≤ 0.05) mean germination percentage over the control. Seeds treated in hot water at 70C for 40 minutes, at 80 C for 30 and 40 minutes, at 90C for 20 and 30 minutes, and at 95C for 10 and 20 minutes, significantly increased (p ≤ 0.05) mean germination percentage as compared to the control. Except for mean root dry weight, other observed growth parameters were significantly higher (p ≤ 0.05) for seedlings grown in media mixed with compost. From these results, it is concluded that mechanical scarification, hot water and sulphuric acid treatments are all suitable pretreatments for maximizing germination percentage and germination rate in D. viscosa subsp. angustifolia. The shrub’s potential to survive and grow in soils sampled from degraded landscapes indicates that this important plant can be used for the restoration of degraded landscapes.enDegraded LandscapeEcological RestorationPioneer PlantRoot Collar DiameterSapindaceaeSeed Coat DormancySeed Dormancy BreakageThesis