Daniel Ofori

Diversity and genetic structure of teak (Tectona grandis L.f) in its natural range using DNA microsatellite markers

Teak (Tectona grandis L.f.) is considered to be an extraordinarily durable building timber with a worldwide reputation. Its widespread use has entailed the over-exploitation of natural forests and a large reduction in natural diversity. Fifteen microsatellite markers were used to study the genetic variability and structure of 166 teak trees distributed over the whole natural area of teak. Analysis showed that in the teak natural area there were four main centers of genetic variability. Two clusters were in India and could be considered as main centers of genetic diversity in teak. The third cluster mainly consisting of populations in Thailand and Laos was genetically very distinct from the Indian populations but presented only half as much allelic variability. A fourth cluster from Central Laos showed even less genetic variability. The use of SSR markers for conservation of teak forest diversity is discussed.

Survival, growth and gall formation by Phytolyma lata on Milicia excelsa established in mixed-species tropical plantations in Ghana

1 Milicia excelsa (Moraceae) is an important timber tree in much of Africa and when grown in monocultural plantations has been subject to nearly complete destruction by gall‐forming psyllids in the genus Phytolyma.

Testing different grafting methods for vegetative propagation of baobab (Adansonia digitata L.) in Kenya to assist its domestication and promote cultivation

Abstract Baobab (Adansonia digitata L.) is an indigenous fruit tree species of drylands in sub-Saharan Africa. Its leaves, fruits and seeds are important for income generation and food and nutrition security of local communities. Its fruit pulp is rich in vitamin C and calcium, among other nutrients. Domestication of baobab, using mother trees with desired traits for vegetative mass propagation and planting, could meet the increasing demand for baobab pulp and the decreasing abundance of the trees in natural habitats. Two grafting methods were tested in the ICRAF nursery site (Nairobi, Kenya) to identify a suitable propagation technique. Two mother trees were selected (Trees 1 and 2) for harvesting scions. ‘Top cleft’ and ‘side veneer’ grafting were performed on a total of 38 rootstocks for each mother tree (20 of 1-year and 18 of 2-year age), resulting in a total of 76 grafted trees. The grafted trees were then followed during eight months. The experiment was conducted to evaluate grafting success and shoot growth. Statistical analyses included Binomial Logistic Regression for survival rates and three-factorial ANOVA for shoot length. The overall grafting survival rate was 63%. Top cleft grafting showed slightly more survival success than side veneer (71% vs. 55%, p = 0.114). Using 2-year old rootstock was significantly more successful than 1-year old ones (75% vs. 53%; p = 0.029). Using scions from mother Tree 1 was significantly more successful than from Tree 2 (82% vs. 45%; p = 0.001). Length of new shoots growing from the scions of the successful grafts did not significantly differ among the treatments. Our results showed that both grafting methods and rootstock ages were successful and can contribute to the development of baobab domestication programmes for improving food security and livelihoods in African drylands.

Trait variations in 28-year-old teak (Tectona grandis) provenance field trials in Ghana, West Africa

Stem straightness, axis persistence, presence/absence of protuberant buds and epicormics, diameter and height have profound influence on timber quality and volume of teak (Tectona grandis). Provenance trials of teak were established in the 1970s in Ghana, as part of the Food and Agriculture Organization (FAO) International Series of Provenance Trials, with the view of selecting teak germplasm for sites with specific environmental conditions. Two field trials were located in dry semi-deciduous (dry) and moist semi-deciduous (moist) ecological zones of Ghana. They consisted of 13 provenances, including four landraces each from Ghana and Indonesia, and two and three provenances from India and Laos, respectively. Trees were assessed at 9, 17 and 28 years to (1) quantify the potential variation in quality and timber volume production, (2) examine possibilities for determining early selection of parameters of superior provenances and (3) select provenances for sites with particular environmental conditions. Production traits were higher on the moist site than the dry site. Mean height was 23.2 and 20.2 m tree−1, stem cross-sectional area at breast height was 0.0896 and 0.0474 m2 tree−1, and stem volume was 0.75 and 0.34 m3 tree−1 for the moist and dry sites, respectively. Nilambur provenance from moist India had the highest mean stem straightness score of 19% above average, whereas Savannakhet from Laos had the best protuberant bud score with 18% of the trees above average. Indonesian landraces performed better in the dry zone, whereas provenances from India and Laos performed better in the moist zone. Phenotypic correlations between age 9 and 28 years were moderate (r 0.54–0.90) to high (r > 0.90) for production and qualitative characteristics, indicating feasibility of early assessment for identification of superior provenances. Nilambur and Savannakhet II provenances proved to be favourable choices for the moist zone, whereas the Temandsang provenance from Indonesia was found to be the best choice for the dry site.

Announcing the Genome Atlas of Bamboo and Rattan (GABR) project: promoting research in evolution and in economically and ecologically beneficial plants

Abstract Bamboo and rattan are widely grown for manufacturing, horticulture, and agroforestry. Bamboo and rattan production might help reduce poverty, boost economic growth, mitigate climate change, and protect the natural environment. Despite progress in research, sufficient molecular and genomic resources to study these species are lacking. We launched the Genome Atlas of Bamboo and Rattan (GABR) project, a comprehensive, coordinated international effort to accelerate understanding of bamboo and rattan genetics through genome analysis. GABR includes 2 core subprojects: Bamboo-T1K (Transcriptomes of 1000 Bamboos) and Rattan-G5 (Genomes of 5 Rattans), and several other subprojects. Here we describe the organization, directions, and status of GABR.

Variation in the response of eastern and southern Africa provenances of Faidherbia albida (Delile A. Chev) seedlings to water supply: A greenhouse experiment

Rural communities value Faidherbia albida in farming systems and pastoralism. Faidherbia albida provides products such as medicine, fodder, fuel, wood, food and services such as shade, soil fertility and nutrient cycling. Excessive browsing by animals, branch lopping and pod harvesting, have critically reduced the natural regeneration in some areas which exposes it to challenges due to dependence upon natural regeneration. The objective of this research was to evaluate response of Faidherbia albida provenances from eastern (Taveta Wangingombe) and southern Africa (Lupaso, Kuiseb Manapools) to different watering regimes to aid in selection of provenances for domestication. The observed difference in growth was analyzed to determine whether they are genetic or environmentally induced. Genotype × interaction were significant at (p≤0.001, p≤0.05) in seedling height, diameter and leaf numbers. Seedling height (r=0.94 p=0.001) recorded the highest correlation coefficient among all the growth variables analyzed. The growth variation was greater for seedling height than that of diameter and leaf numbers (h2=0.97). Hierarchical cluster analysis grouped the provenances into three clusters with cluster iii consisting of Taveta, Kuiseb and Lupaso while cluster ii and i composed of Wangingombe and Manapools respectively. Manapools recorded the highest genetic distance from Taveta, Kuiseb and Lupaso at 84.55 units. Wangingombe and Manapools are closely related genetically at a distance of 7.32. The maximum inter-cluster distance between cluster i and iii indicated wider genetic diversity between the provenances in these clusters and selection should be from this clusters for hybridization program to achieve novel breeds.