Survey of Potato aphid (Myzus persicae) from Selected on-farm Potato growing Areas in Mbeya and Njombe regions of Tanzania

Potato aphid green peach (Myzus persicae Sulzer) is one of the serious pests in potato (Solanum tuberosum) production areas in the world. A survey was carried out during 2014 potato growing season to assess aphid and Coccinellid population abundance in potato production areas in Mbeya and Njombe regions situated in southern highlands of Tanzania. Aphid and Coccinellid abundance were sampled from 30 leaves selected randomly from ten plants. Estimates of aphid abundance from potato fields were carried out from transectline replicated three times. A total of 1,370 aphid populations were sampled during the survey period. Abundance from young leaves was 898, followed by medium leaves 270 and the least was old leaves represented by 202 individuals. The relative abundance of aphid population resulted from 15 minutes sampling effort per transect ranked from 8 individuals from Swaya village to 171 individuals from Atwelo village and the rest were in between. The differences between selected plant parts showed significant differences (p = 0.001). The results from this survey provides database on aphid population and Coccinellid natural enemies of potato aphid in potato growing areas which can be used for future research in the selected regions. Key words: Myzus persicae, potato aphid, Coccinelli

ANT SPECIES DIVERSITY AND COMPOSITION AT MLINGANO MANGO ORCHARD IN TANZANIA

ABSTRACT: Ants are major decomposers and they are sensitive to any human influence in our environment. Presence or absence of ants in cropland habitat is resulted from alteration of forest habitat into cropland. Ant's species diversity in mango orchard was considered as an important biodiversity indicator due to alteration of the primary forest into cropland habitat. Ants were sampled from mango trees searching species of ants from tree bases to 2M high. Dental rolls with 10% sugar as attractant bait were also used to attract ground preference of ant species. Attractant bait was placed on a tree base for 30 minutes and thereafter inspected for data collection. This study has revealed that ant species composition in mango orchard varies according to cropping system. Dominance of species was Crematogaster followed by Pheidole megacephala and the least was Oecopyhlla longinoda ants. Comparison of species composition revealed that there were significant differences. Species with low representative individuals were considered as extinct or rare species. The intended study was carried out at Mlingano mango orchard with the aim to determine the ant's species diversity and composition. The results from this work will help in developing sustainable biodiversity conservation programmes as well as for future research

Study of genetic diversity and micropopagation of Coffea arabica L. and evaluation of genetic diversity in Cocos nucifera L. from Tanzania

RAPD and ISSR markers were used to analyze diversity in Coffea arabica L. and Cocos nucifera L. In coffee, both markers revealed within-provenance dissimilarity values that were lower than between-provenance values which accentuates the inbreeding nature of C. arabica and the effect of farmers’ selection. ISSR analysis separated diploid coffee species from C. arabica. Overall provenances from the same location clustered together, provenances from Mbeya were clearly differentiated from the rest. In Cocos nucifera L. RAPD markers were used to analyse 120 accessions. Data were analysed by clustering based on Jaccard’s (1908) coefficient and Nei genetic distances. Further analysis involved principal coordinate analysis (PCA) and bootstrap analysis. The results were able to discriminate between the different provenances and provide evidence of the different origins for the coconut palms in the northern and southern parts of Tanzania. The two major clusters also concur well with the history and distribution of coconuts in Tanzania. Development of a micropropagation protocol for new Coffea arabica L. varieties proceeded with testing five varieties on several media. Several benzyladenine (2.5, 5 and 10 μM) and triacontanol (2.85 and 11.38μM) combinations were tested. Segments from different positions of the leaf were tested for their ability to produce embryos. Leaf segments did not differ in percent embryo-producing explants. BA had the most impact on the number of embryo-producing explants. The best combination of BA/TRIA was 10μM BA and 11.38μM TRIA. The presence of TRIA caused an increase in embryo-producing explants