Tanzania has a diverse agroecological area suitable for growing tropical fruits, including avocados. In Northern Tanzania, avocados have been growing under variable soil and altitudinal characteristics for over 100 years, allowing the naturalisation of this crop in this region. However, the region's avocado germplasm is uncharacterised, thus impeding the selection of elite genotypes for increased value and breeding programmes. This study examined the growth and fruit morphometric characteristics of avocado populations grown under variable soil pH and altitude in six districts in the Tanga, Kilimanjaro and Arusha regions. Variations in growth and fruit morphometric characteristics were compared using a one-way analysis of variance (ANOVA). Pearson product-moment correlations (r) were used to evaluate the relationship between studied growth and fruit morphometric traits. A linear mixed-effects model (LMM) was used to assess the influence of the soil pH, altitude, tree height, canopy diameter, and trunk diameter on fruit length, fruit diameter, pulp thickness, and seed diameter. Principal Component Analysis (PCA) was used to depict the extent of the racial admixtures in the avocado germplasm in the Northern regions of Tanzania. The results revealed a significant variation in growth and fruit morphometric characteristics (p < 0.05). The Korogwe population had the highest tree height, while the Karatu had the lowest. Tree height was positively correlated with the trunk diameter (r = 0.63, p < 0.001. There was a positive correlation between fruit length and pulp thickness (r = 0.51, p < 0.001), fruit diameter and pulp thickness (r = 0.47, p < 0.001), and fruit length and fruit diameter (r = 0.36, p < 0.001). The fruit diameter was positively correlated with the seed diameter (r = 0.61, p < 0.001). There was a significant but weak association between fruit length and trunk diameter (-0.01), fruit length and canopy diameter (0.15), and between seed diameter and tree height (2.95e-2). These findings highlight the influence of individual tree genetic makeup on the variation in growth and fruit morphometric characteristics. The morphometric trait correlations may prove valuable in field measurements, especially when resources are limited. The study further indicates the presence of all avocado races within the local germplasm, highlighting its high diversity. Remarkably, the observed admixture of variant races implies gene flow among studied avocado populations, possibly facilitated by sharing seedlings among farmers or seed disposal through avocado fruit trading. Further study is needed, particularly in quantifying the above-ground biomass of local avocados in northern Tanzania, potentially contributing to carbon credit initiatives for fruit crops..

The study assessed climate change adaptation options and their implications on mangrove resources in Bagamoyo District. A total of three villages and 158 respondents were involved. Close and open-ended questions and FGDs were used to collect quantitative and qualitative data. Descriptive and content analysis was used for qualitative data while SPSS (Version 20) and Microsoft excel were used for quantitative data analysis. Results indicated that, majority of respondents (>80%) were aware of the climate changes and majority perceived rainfall (Kaole 72.7%, Kondo 70% and Mbegani 43.9%) as a major climate change indicator. Analysis of the empirical data from TMA showed a decline of rainfall (y = -3.8748x + 978.1) and an increase of earth’s surface temperature of an average of 0.8°C (y = 0.4142x + 21.655) from 1985-2015. Unpredictable and shortage of rainfall and increased earth’s surface temperature in combination acted to reduce agricultural yields and fish catch in the surveyed villages. Different climate change adaptation strategies identified in the surveyed villages include; expansion of farms, modifying fishing activities and engagement into different income generating activities such as casual labour, and petty businesses. The identified adaptation options in Kaole seemed to have positive implications on mangroves resources i.e. effective mangrove restoration programmes while those identified in Mbegani and Kondo i.e. weak mangrove restoration programmes, commercial firewood and charcoal making were unsustainable and had negative implications on mangroves resources. Further studies on climate change adaptation, awareness raising and scientific studies on mangroves species composition, richness and restoration in a changing climate are recommended to enhance coastal community adaptive capacity and effective management of coastal resources.