CHROMOSOME NUMBERS OF SOME INDIGENOUS TREE SPECIES OF ETHIOPIA

Abstract

Chromosome data are essential information for any organism and many chromosome investigations have been performed, providing
important characters for plant systematic and evolutionary analysis as well as for germplasm improvement. Trees are important to the wellbeing of people in every country, as they have essential ecological, economic and cultural values. In Ethiopia, there are over 300 tree species. However, for most of the country’s tree species, chromosome data are not available in the literature. The present investigation was aimed at carrying out mitotic chromosome studies on some important indigenous tree species of Ethiopia. Somatic chromosome counts were carried out on somatic cells from root tips. In this study, chromosome numbers for the following twelve tree species from ten genera of seven families are reported: Cordia africana 2n=48, Acacia abyssinica 2n=104, Acacia senegal 2n=26, Erythrina brucei 2n=42, Acacia albida 2n=26, Millettia ferruginea 2n=22, Ficus sur 2n=26, Ficus sycomorus 2n=26, Olea europaea subsp. cuspidata 2n=46, Podocarpus falcatus 2n=24, Ziziphus spina-christi 2n=24, and Allophylus abyssinicus 2n=28. Counts on all the species are reported for the first time for Ethiopian materials and six of the counts are initial species reports. For A. abyssinica and Z. spina-christi, new chromosome numbers are reported. Metaphase chromosome microphotographs are presented for all the species studied.