Morphological and genetic diversity of persea americana mill. (avocado) using microsatellites in the Ashanti and Central regions of Ghana

Abstract

Avocado (Persia americana Mill) is a nutritious economic tree crop with cultivations scattered all over the country. A study was conducted to assess its distribution, uses and the morphological and genetic diversity of the crop in the Ashanti and Central Regions of Ghana. An ethnobotanical survey was carried out in 14 districts, while morphological and genetic diversities were determined among the accessions in eight districts. Microsatellites markers were used for genetic diversity studies. Growth of the plant was better in the Ashanti Region than in the Central Region and it thrived best in old cocoa farms. The crop was mainly cultivated on a small scale. Parts of the plant were used for various medicinal and economic purposes. Morphologically, they were mainly of Western Indian origin. However, accessions from the Ashanti Region more diverse in the plant and fruit characters compared to the Central Region. Microsatellites analyses revealed 115 different amplification fragments, ranging from 5 to 22 alleles per locus, with an average of 11.5 alleles per locus. All the microsatellites were highly informative, with both genetic diversity and polymorphic informative content (PIC) higher than 0.5. Using the Unweighted Pair Group Method with Arithmetic Averages (UPGMA), the genotypes were clustered into seven major groups. The wide genetic diversity among the accessions indicates that there is a wide genetic base for improvement of the crop through breeding and selection in Ghana.