OPTIMIZATION OF EFFICIENT PROTOCOL FOR In vitro MASS PROPAGATION OF SELECTED ACCESSIONS OF AVOCADO (Persea americana) MILL. BY AUXILIARY AND APICAL BUDS CULTURE

Despite the significant economic importance of avocado, pathogens infection, low yielding varieties and inappropriate farming mainly affected productivity of avocados. The development of vegetative propagation methods using tissue culture techniques such as apical buds, and auxiliary culture promote agricultural productivity. A protocol for mass propagation of avocado from apical and auxiliary buds of three Ethiopian avocado accessions was developed. A lower percentage of contaminated explants (10%) were exhibited in the sterilization treatment combinations of one drop Tween 20 and 1% fungicide for 5min plus 70% ethanol for 1min plus 1% NaClO for 5 min. The highest mean number of shoots were obtained on MS medium containing 0.125 mg/L IBA and 0.125mg/L IAA from Arba Minch chano mille accession, 0.125 mg/L BAP + (0.125 mg/L IBA or 0.125 mg/L IAA) from Teppi accession and 1.0 mg/L BAP + (0.125 mg/L IBA and 0.125 mg/L IAA) from Buta-Jira avocado accession. The maximum mean number of roots (1.86±0.12) and (1.50±0.08) were obtained on MS-medium containing 1.0 mg/L IBA and 1 mg/L NAA hormone, respectively. During acclimatization, ~54% of the plants were survived and adapted in the field conditions. The hormone combination of 0.125 mg/L IBA and free 6-BAP was the best for shoot initiation from Arba Minch chano mille and Teppi avocado accessions while 1 mg/L BAP and IBA was the best for Buta-Jira accession. The effective hormone concentration for rooting of both shoots initiated from apices and auxiliary buds was MS medium supplemented with 1 mg/l IBA.