Characterization and Morphological Diversity of Local Avocado Germplasm ( <i>Persea americana</i> Mill.) from Northern Tanzania

Tanzania’s diverse agroecological zones offer ideal conditions for cultivating tropical fruits, including avocados, which are economically and nutritionally important. This study assessed the morphological diversity of seed-propagated avocado germplasm from Northern Tanzania’s Tanga, Kilimanjaro, and Arusha regions. Two hundred seventy mature avocado trees were sampled from farmers in two districts per region. The samples were characterized using 14 descriptor variants from the International Plant Genetic Resources Institute (IPGRI) avocado descriptor list. Quantitative traits were analyzed through one-way Analysis of Variance (ANOVA) with populations (districts) and altitude ranges as factors. Qualitative characteristics were assessed using cross-tabulation, Chi-square, and Fisher’s exact tests. Linear Discriminant Analysis (LDA) and Hierarchical Cluster Analysis (HCA) explored morphological diversity relationships. The results revealed significant variation in quantitative traits (p < .05). Karatu and Meru had the highest number of primary leaf veins (18.84 ± 0.16), while Rombo had the lowest (15.13 ± 0.09). Karatu, Meru, Moshi and Rombo displayed the highest leaf vein divergence (42.33 ± 0.33), and Lushoto the lowest (37.78 ± 0.36). The study observed diverse morphological traits, predominantly of the Mexican and Guatemalan races, with some West Indian traits concentrated in Rombo. Novel morphological variants absent in the IPGRI guidebook were recorded. LDA suggested slight geographical clustering within regions, while Rombo trees formed distinct clusters. The dendrogram revealed admixture across populations, indicating gene flow through seed movement. This study confirms the value of morphological markers in detecting avocado diversity in varying agroecological conditions. It underscores the high morphological diversity of Northern Tanzania’s avocado germplasm, emphasizing its conservation and breeding potential.