NATIVE MYCORRHIZAE FROM ETHIOPIA IMPROVE TREE GROWTH AND SEEDLINGS SURVIVAL CONTRIBUTING TO THE GREEN LEGACY PROGRAM

Abstract

Background: A rapid production of tree seedlings in nurseries with a high survival rate after transplanting is important to respond to the current demand for programs of restoration of arid environments by forestation. The low level of seedlings’ survival and establishment, caused by low moisture and nutrient content of soils, has been a bottleneck to reaching the target of the forest national restoration in Ethiopia of last years. It is suggested that, inoculation with root-associated plant growth promoting microorganisms could help to ameliorate this scenario and also respond to the Ethiopia's Green Legacy Program. Objective: To assess the potential of inoculation with arbuscular mycorrhizal fungi (AMF) native to Ethiopia to improve the survival and growth of trees that could be used in afforestation programs in Ethiopia. Methodology: The study was carried out in three stages: (1) soil samples associated with roots of selected acacia species (T1-AMF of A. abyssinica, T2-AMF of A. seyal, T3-AMF of A. tortilis and T4-Control) were collected of highland and lowland areas from Ethiopia, (2) Sorghum (Sorghum bicolor (L.), provided by the Melkasa Agricultural Research Center-(MARC) served as a trap plant for the AMF consortium multiplication and (3) plant growth promotion by AMF was assessed throughout inoculations of seedlings of Delonix regia (Hook.) Raf., Sesbania grandiflora (L.), Cassia fistula L., and Azadirachta indica A. Juss., trees. Results: All inoculated seedlings showed significantly greater responses in all growth and mycorrhizal parameters over the non-inoculated trees. Consortium T2-AMF associated to roots of A. seyal from lowlands of Batu, showed significantly greater responses in all plant growth and mycorrhizal parameters over the AMF inoculums associated to other tree species evaluated. Significant and positive correlations were found between mycorrhizae and plant-growth parameters. Implications: Our results suggest that inoculation with native arbuscular mycorrhizal fungi indigenous from Ethiopia has the potential to significantly enhance survival and growth rates of tree seedlings. This could thereby advance national reforestation goals and addressing challenges in seedling establishment in arid environments. Conclusion: The potential for growth promotion and establishment of tree seedlings evidenced, implies that further efforts should be directed towards the in-mass production of AMF-based inoculants, particularly associated with A. seyal roots.

Keywords

• acacia trees
• mycorrhizal fungi
• forestation program
• inoculation
• seedlings