Clonal variations in seed characters and germination in Hevea brasiliensis

The principal form of dissemination for most plant species is seeds, an important source of biodiversity conservation. For rubber plantations, seeds are the initial material for seedling production. In Cameroon, there is limited information related to clonal seed characterisation and early growth performance. This study sorts to characterise Hevea brasiliensis seeds from GT 1, PR 107, PB 217, PB 235, and PB 260 clones and evaluate the germination rate and seedling early growth characteristics to enable planning for nursery management. Clone GT 1 had the highest seed length (3.98 cm), seed kernel weight (3.4 g) and total seed weight (4.75 g). Clone PB 235 had the heaviest shell (1.96 g). There was no significant correlation between seed size, germination percentage and early seedling growth for the different clones. Clone PR 107 had the lowest per cent seed germination, with just 55 per cent of its seed germinating after two weeks, whereas clone PB 217 had the highest seed germination (92.5%). Seedling height, seed germination percentage and shell weight were significantly correlated. The results of this study provide some useful information for rubber nursery managers

Carbon Storage of some Rubber Trees (<em>Hevea brasiliensis</em>) Clones in HEVECAM’s Plantations in South Cameroon

The objective of this work was to estimate the quantity of carbon stored by four main clones of rubber tree cultivated in South Cameroon: GT 1, PB 217, PR 107 and RRIC 100. The forest inventory method was used to measure trees morphological parameters, the latter used to calculate carbon storage using the allometric equation of Wauters et al., (2008). The main morphological parameters measured were: leaf area index (LAI), circumference (C), diameter at breast height (DBH) and total tree height (h). Comparing the morphological parameters of clones two by two using a Dunn test, we observe significant differences in the circumference, the diameter and even very significant in the leaf area index, but not in the height. The clones GT 1, PR 107, PB 217, and RRIC 100 stored on average: 111.05 tC / ha, 150.18 tC / ha, 165.25 tC / ha, and 187.25 tC/ha respectively. A significant difference was established between the means of carbon storage of the clones GT 1 and PB 217 (p = 0.0488) on one hand and, that of the clones GT 1 and RRIC 100 (p = 0.0240), on the other hand. These results are an estimation of models, further research can be undertaken for exact measurements

Farmer’s Perception of Associates Non-Cocoa Tree’s Leaf Litterfall Fertilizing Potential in Cocoa-Based Agroforestry System

Investigations to assess farmer’s perceptions on the fertilizing potential of associated trees species in cocoa agroforest of degraded forest ecology were carried out in southern Cameroon. The perception of the farmers was based on the ability of the trees to maintain or improve soil fertility of their farms. The verification of these perceptions was done through an evaluation of litter fall biomass nutrient content (N, P, K, Ca and Mg) of selected trees. The top 5 associates trees ranked by farmers was: Milicia excelsa, Ceiba pentandra, Ficus mucuso, Asltonia boonei, Terminalia superba. The chemical analysis of the leaf litter from the different tree species revealed a significant different between their chemical components. N appeared to have the highest concentrations varying from 2.82 to 5.57% with a mean value of 4.25 ± 1.065%, P had the lowest concentrations typically around 0.001%. The top 5 tree species based on the chemical analysis ranking were: C. pentandra, M. excelsa, Eribroma oblungum, Alstonia boonei, Zanthoxylum heitzi. Farmer’s perceptions thou holistic, are not completely different from scientific finding. Therefore, they should be taken in consideration in management plans for cocoa- based systems in order to enhance their ecological and economic performance