Edward Missanjo

Effect of Seed Size and Pretreatment Methods on Germination of Albizia lebbeck

Albizia lebbeck is a multipurpose tree species prioritised for conservation in Malawi. The different plant parts are used in traditional medicine to treat different diseases. However, the seeds are dormant, and the tree species remain undomesticated. A study was conducted to evaluate the effect of seed size and presowing on the germination of Albizia lebbeck in a nursery. Seeds were grouped into four categories in regard to their length, small (≤0.5 cm), medium ( cm), large (≥0.8 cm), and mixture of small, medium, and large seeds. The seeds were subjected to five main seed pretreatment methods, namely, soaking in sulphuric acid for 2 minutes, nicking, soaking in hot water for 5 minutes, soaking in cold water for 24 hours, and control where seeds were sown without any treatment. The results indicate that combination of nicking and large seeds produced the highest (100%) germination. Hot water treatment was effective in large seeds producing 67.5% germination. The increased germination for mechanically scarified seeds through nicking suggests that seed dormancy in Albizia lebbeck is mainly due to its hard seed coat. Therefore, it is recommended to farmers to adopt use of nicking and large seeds, since it is safe and effective.

Estimation of Genetic and Phenotypic Parameters for Production Traits and Somatic Cell Count for Jersey Dairy Cattle in Zimbabwe

Genetic and phenotypic parameters for production traits and somatic cell count (SCC) for Jersey dairy cattle in Zimbabwe were estimated. A total of 10986 lactation records were obtained from Zimbabwe Livestock Identification Trust, with cows calving in the period from 1996 to 2008. An ASReml program fitting an animal model was used for the analyses. Heritability estimates for milk yield, fat yield, protein yield, fat percentage, protein percentage, and Log10SCC were 0.30, 0.32, 0.33, 0.42, 0.44, and 0.08, respectively. The corresponding repeatability estimates were 0.39, 0.38, 0.39, 0.49, 0.51, and 0.16, respectively. The genetic and phenotypic correlations between different production traits ranged from −0.86 to 0.95 and from −0.88 to 0.98, respectively. The genetic and phenotypic correlations between production traits and Log10SCC were weak almost nonsignificantly differentl from zero. The results imply that milk traits for Jersey dairy cattle in Zimbabwe are more heritable. Therefore, these traits may be preferred by breeders as selection criteria for development of effective genetic improvement programme.

Effects of Different Pretreatments to the Seed on Seedling Emergence and Growth of Acacia polyacantha

Acacia polyacantha Willd. is a multipurpose tree species prioritised as one of the agroforestry tree species in Malawi. However, its use in agroforestry practices is limited by the low seedling growth and survival at the nursery stage. A study was conducted to evaluate the seedling growth and survival of Acacia polyacantha as affected by different pretreatments on the seeds at Malawi College of Forestry and Wildlife nursery, Malawi. Seeds were subjected to five presowing seed treatments methods, namely, immersion in cold water at room temperature for 24 hours, immersion in hot water (100°C) for 5 minutes, immersion in concentrated sulfuric acid (0.3 M H2SO4) for 20 minutes, scarification by mechanically nicking using secateurs, and a control where seeds were sown without any treatment. The results indicate that presowing seed treatments have positive influence on the seedling growth and survival percentage. Nicked seeds exhibited the highest significant () performance for vegetative characteristics of height, root collar diameter, number of leaves, and survival percentage compared to other pretreatments. Therefore, it is suggested to use nicking as a pretreatment method on Acacia polyacantha seeds in order to enhance the speed and the amount of early seedling growth at the nursery stage.

Evaluation of Natural Regeneration and Tree Species Diversity in Miombo Woodlands in Malawi

Evaluation of Natural Regeneration and Tree Species Diversity in Miombo Woodlands in Malawi A study was conducted to determine the best silvicultural practice to maximise natural regeneration and tree species diversity in miombo woodland in Chongoni Forest Reserve in Malawi. Four trial plots of 50m x 25m with about 10m buffer zone were each subjected to one of the following silvicultural practices: Complete coppice (CC); coppice with standard (CWS); selective thinning (ST); and control was leave it alone (CT). The treatments were completely randomized in three replicates. Twenty years after establishment of the plots an inventory on natural regeneration and tree species diversity was carried out. The results indicate that selective thinning had higher natural regeneration, mainly because of one species, although the differences among silvicultural practices were not significant. Coppice with standard was observed to have the highest tree species diversity. Therefore, coppice with standard has been recommended as one of the future management options in management of miombo woodlands in Malawi in order to maximise tree species diversity whilst maintaining good site cover.

Effect of Seed Size of Afzelia quanzensis on Germination and Seedling Growth

Afzelia quanzensis Welw is a valuable timber producing tree species in Africa. A study was conducted to evaluate the influence of seed size on seed germination and seedlings quality of Afzelia quanzensis. Seed was categorized into three groups in regard to their length, small (<1.5 cm), medium (≥ 1.5 ≤ 2.5 cm), and large (>2.5 cm). The treatments were completely randomized into four replications. Germination percentage was not significantly different between the treatments, although large seeds had the highest germination percentage of 94.9%. There were significant differences in seedling height and root collar diameter among the different seed sizes, with large seeds having the highest seedlings height and largest root collar diameter. This was attributed to differences in the food reserves. Survival of transplants from shoot dieback was significantly different such that seedlings from large seed attained the highest survival of 92%. It is therefore recommended that, for production of high quality transplants in the nursery, large seeds should be used.

Phenotypic Variation in Fruit Morphology among Provenances of Sclerocarya birrea (A. Rich.) Hochst.

Sclerocarya birrea (A. Rich.) Hochst. is a multipurpose fruit tree which is very useful in providing food security and meeting nutritional and economic needs. This study was conducted to assess eighteen provenances of Sclerocarya birrea planted in Mangochi, Malawi. The trial was assessed for fruit traits at fifteen years of age. There were significant () variations among the provenances in number of fruits, fruit weight, pulp weight, seed weight, fruit length, and diameter. Magunde provenance from Mozambique had the highest mean number of fruits, 2196 ± 200. Mangochi and Moamba provenances from Malawi and Mozambique were the most outstanding in the other parameters measured attaining the mean fruit weight of 20.89 ± 0.25 g and 25.67 ± 0.67 g, pulp weight of 25.70 ± 0.08 g and 21.55 ± 0.83 g, seed weight of 4.81 ± 0.35 g and 4.12 ± 0.18 g, fruit length of 2.61 ± 0.14 cm and 2.33 ± 0.07 cm, and fruit diameter of 2.33 ± 0.15 cm and 1.97 ± 0.08 cm, respectively. There was no significant () correlation between number of fruits and the other fruit traits. However, there were significant () and strong positive relationships between fruit weight and pulp weight () and fruit length and diameter (). This suggests that fruit weight can be used indirectly for selection of pulp. Further studies should investigate fruit taste quality of products from the fruits.

Estimation of Genetic and Phenotypic Parameters for Growth Traits in a Clonal Seed Orchard of Pinus kesiya in Malawi

Genetic and phenotypic parameters for height, diameter at breast height (dbh), and volume were estimated for Pinus kesiya Royle ex Gordon clonal seed orchard in Malawi using an ASReml program, fitting an individual tree model. The data were from 88 clones assessed at 18, 23, 30, 35, and 40 years of age. Heritability estimates for height, dbh, and volume were moderate to high ranging from 0.19 to 0.54, from 0.14 to 0.53, and from 0.20 to 0.59, respectively, suggesting a strong genetic control of the traits at the individual level, among families, and within families. The genetic and phenotypic correlations between the growth traits were significantly high and ranged from 0.69 to 0.97 and from 0.60 to 0.95, respectively. This suggests the possibility of indirect selection in trait with direct selection in another trait. The predicted genetic gains showed that the optimal rotational age of the Pinus kesiya clonal seed orchard is 30 years; therefore, it is recommended to establish a new Pinus kesiya clonal seed orchard. However, selective harvest of clones with high breeding values in the old seed orchard should be considered so that the best parents in the old orchard can continue to contribute until the new orchard is well established.

A Mixed-effects Height-Diameter Model for Pinus kesiya in Malawi

A Mixed-effects Height-Diameter Model for Pinus kesiya in Malawi A height-diameter model was developed in order to predict the total height of individual trees in Pinus kesiya in Malawi. Six generalized height-diameter models were fitted and evaluated based on data set consisting of 18156 tree heights and corresponding diameters at breast height. The data were collected during three inventories of 332 permanent plots located in Chongoni, Malawi. A model including the diameter at breast height of the tree, stand age, site index, and basal area as independent variables was selected as the best model. To deal with the problem of among-unit variability, a non-linear mixed effects modelling approach was used to fit the selected model. The mixed model included a random parameter that affected the model and provided realistic height predictions. The equation developed represents a new tool for evaluation and management of Pinus kesiya stands in the region.

Impact of Site Disturbances from Harvesting and Logging on Soil Physical Properties and Pinus kesiya Tree Growth

A study was conducted to determine the impacts of soil disturbance and compaction on soil physical properties and tree growth and the effectiveness of tillage in maintaining or enhancing site productivity for intensively managed Pinus kesiya Royle ex Gordon sites in Dedza, Malawi. The results indicate that about fifty-two percent of the area of compacted plots was affected by the vehicular traffic. Seventy percent of the trees were planted on microsites with some degree of soil disturbance. Soil bulk density at 0–20 cm depth increased from 0.45 to 0.66 Mg m−3 in the most compacted portions of traffic lanes. Soil strength in traffic lanes increased at all 60 cm depth but never exceeded 1200 kPa. Volumetric soil water content in compacted traffic lanes was greater than that in noncompacted soil. Total soil porosity decreased 13.8% to 16.1% with compaction, while available water holding capacity increased. The study revealed no detrimental effects on tree height and diameter from soil disturbance or compaction throughout the three growing season. At the ages of two and three, a tree volume index was actually greater for trees planted on traffic lanes than those on nondisturbed soil.

Growth and Survival of Pinus Seedlings as Influenced by Different Mycorrhizae and Ordinary Soil Ratios in a Nursery

Growth and Survival of Pinus Seedlings as Influenced by Different Mycorrhizae and Ordinary Soil Ratios in a Nursery A study was conducted to determine the effect of different mycorrhizae and ordinary soil ratios on height growth, root collar diameter growth, survival and root colonisation of pinus seedlings in a nursery for sixteen weeks. Seedlings were subjected to six different mycorrhizae to ordinary soil ratios treatments which were completely randomised in four replicates, namely: 1:0, 1:1, 1:5, 1:10, 1:20 and 0:1(100% ordinary soil) as a control. The results indicate that there was a significant difference on the mean height growth, root collar diameter, survival rate and root colonisation of the seedlings. The treatment of soil ratio of 1:0 (mycorrhizae to ordinary soils) had the highest mean height, root collar diameter, survival rate and root colonisation than the other treatments. These means that height, root collar diameter, survival rate and root colonisation of seedlings decreased with an increase of ordinary soils. Therefore, mycorrhizae soils are essential in the raising of pinus seedlings in the nursery and where pinus plantations are well established, the treatment ratio of 1:0 (100% mycorrhizae soils) is recommended for inoculating pinus seedlings at the nursery.