Within- and between-provenance variations in seed and seedling traits of Khaya senegalensis A. Juss were studied at INERA in Burkina Faso. Nursery grown seedlings from four provenances in Burkina Faso were used for the study. The studies revealed significant variability in all traits evaluated. Seed length and weight significantly varied among provenances and families within provenances, where Bopiel and Koyenga had the highest mean values. Height and root collar diameter of 1 year old seedlings significantly varied among families within provenances. Except leaf biomass ratio and carbon isotope ratio which varied significantly among provenances but not among families within provenances, all other seedling biomass traits-total plant biomass, stem biomass ratio, leaf biomass ratio, root biomass ratio, root shoot ratio, specific leaf area, and leaf area ratio were significantly affected by provenances and families within provenances. The magnitude of variation due to family effect ranged from 65 to 93 % for seed size traits, and from 4.5 to 17.8 % for seedling characters. Estimates of family heritability were moderate to high (0.67-0.95) for seed traits, but low to moderate (0.19-0.59) for seedling characters, indicating that much of the total variation in seed traits is due to the genetic effect. The two most prominent provenances, Koyenga and Bopiel, with higher seed size and greater seedling growth could be considered for an eventual K. senegalensis improvement program in Burkina Faso.
Tag: genetic variation
Provenance evaluation of Calliandra calothyrsus meissner in the humid lowlands of Cameroon
Calliandra calothyrsus has been reported to have potential for agroforestry in the humid lowlands of West and Central Africa. Provenance evaluation of the species was initiated in Yaounde, Cameroon with the objective of identifying adapted provenances with desirable traits for inclusion in evaluation of the management of various agroforestry technologies being developed for the humid lowlands of the region. Fifteen provenance seed collections from Central America and southeast Asian sources were included in the trial. Results indicate that enormous genetic variation exists between these provenances. The highest yielding provenance produced 1.8 and 2.5 times, respectively, wood and leaf biomass compared to the lowest yielding provenance. Most of the provenances evaluated flowered during the first six months after establishment while all the provenances (15) flowered by the end of the first year. However, this initial flowering did not result in productive pod development and seed setting. Two years after planting, the trees were cut at a height of 0.05 m above ground level, and more than 80% of the stumps of all the provenances re-sprouted. Leaf nitrogen content ranged between 2.25% and 2.78% of dry weight. Six provenances had above average values in at least five of the six desirable traits considered i.e.: height, growth, stem development, leaf biomass, wood biomass, leaf litter productivity and total nitrogen content of leaves; these are recommended for further testing for inclusion in appropriate technologies for soil fertility improvement.
Genetic diversity in Guazuma crinita from eleven provenances in the peruvian amazon revealed by ISSR markers [Diversidad genética de Guazuma crinita en once procedencias de la Amazonía Peruana revelada por marcadores ISSR]
Guazuma crinita is an important fast-growing timber tree species widely used in agroforestry systems in the Peruvian Amazon. The objectives of our research were (i) to assess genetic diversity of G. crinita using inter-simple sequence repeat (ISSR) markers and (ii) estimate correlation between genetic and geographic distances among provenances. The sample included 44 genotypes from 11 provenances in the Aguaytia and neighboring Pachitea watersheds in the Peruvian Amazon. Ten ISSR primers amplified a total of 65 bands of which 61 were polymorphic (93.8%). The range of DNA amplification varied from 260 to 2,200 bp. Among the provenances, Macuya exhibited the highest percentage of polymorphic bands (PPB) with 67.7%, 0.21 Nei’s gene diversity (He) and 0.33 Shannon index (I). Overall genetic differentiation (Gst) was 0.03, indicating 97% of genetic diversity within provenances. Gene flow (Nm) was 12.9 alleles per generation. Cluster analysis was not related to geographic origin, suggesting a common gene pool. However a weak positive correlation (r = 0.27, P < 0.05) was found between genetic and geographic distance. This is the first study of genetic diversity and structure of G. crinita. We recommend in situ conservation strategies for populations with high levels of genetic diversity. © 2016, Universidad Austral de Chile. All rights reserved.
First and second generation research effort on commodising indigenous fruit tree crops in southern Africa
Harvesting of indigenous fruits from the wild provides important food supplements and cash income for many people in the rural communities. Household analysis in Southern Africa indicated that indigenous fruits can reduce vulnerability of rural households to income poverty and food insecurity. Research efforts on indigenous fruit trees in Southern Africa involved two interconnected phases. The first generation phase which included the development of long-term domestication strategies, selection of priority species, tree germplasm collection and genetic improvement, propagation systems, and field management. The second generation phase included participatory development of superior cultivars, analyses of production economics, adoption, post-harvest handling, enterprise and product development, and market research of indigenous fruits. This paper synthesises first and second generation research carried out on indigenous fruit tree domestication, utilisation, and commercialisation in Southern Africa. It also presents the lessons learned and provides the way forward to enhance food security and income generation in Southern Africa.
Genetic variability and divergence of seed traits and seed germination of five provenances of Faidherbia albida (Delile) A. Chev
Establishment of Faidherbia albida trees on farm is often difficult despite the plant survival adaptive mechanisms such as drought and disease resistance. Adoption of the tree to agroforestry systems is also limited due to lack of knowledge on genetic variation of its provenances. Morphological charac-terization of F. albida provenances is therefore necessary to screen for natural genetic variation in seeds traits for selection of germplasm for long term agroforestry, timber production, fodder, soil fertility increment and environmental sustainability. In this study, seed traits of five provenances of F. albida: Taveta Wangingombe, Lupaso, Kuiseb and Manapools were examined. Divergent studies were analyzed based on seed morphology and geo-climatic conditions of the provenances. Seed length, width, thickness and weight were analyzed to determine the extent of phenotypic and genotypic variance and heritability. This study revealed significant differences among provenances (P=0.05) for all the studied characters indicating substantial genetic variability. Genetic variance for all seed traits was higher than environmental variance suggesting that the expressions of these traits are under genetic control. This result was supported by high heritability values for seed length (0.92), width (0.99), thickness (0.99) and weight (0.99). Seed germination test involved 4 replicates of 25 randomly selected seeds per provenance. Mean germination percentage among provenances was 83.3% with the highest being 97% and the lowest 71%, P=0.05. Relationships among these variables were analyzed using principal component analysis and cluster analysis resulting in separation of provenances into three distinct clusters. Manapools (760 mm), Lupaso (1165 mm) and Wangingombe (628 mm) with high rainfall were placed in cluster one. Taveta (545 mm) cluster two and Kuiseb (0.5) for all traits suggests that selection based on morphological traits can be made with a high degree of confidence.
Genetic divergence in Jatropha curcas L., a potential biofuel crop in Kenya
Background: The aim of this research was to estimate the genetic divergence among 49 genotypes of Jatropha curcas L. and to identify potential parental lines needed for breeding high oil and seed yielding cultivars. Methodology: The genotypes were studied for several agronomic traits including: plant height, days to flowering (50%), male:female flower ratio, number of fruits, seed yield, 100-seed weight and oil content. Genetic divergence was measured using Mahalanobis’ D2 statistics and Tocher cluster methods. Results & conclusion: The most diverse genotypes were those from different geographical origins, suggesting a relationship between genetic and geographical diversity. Hybridization of genotypes from East Africa with those from Madagascar and Mexico would generate high-level genetic divergence
Analysis of genetic diversity in accessions of Irvingia gabonensis (Aubry-Lecomte ex O’Rorke) Baill
Amplified fragment length polymorphism (AFLP) was used to assess genetic diversity and relationshipsamong 15 accessions of Irvingia gabonensis collected from Cameroun, Gabon, and Nigeria. TwelveAFLP+3 primers produced 384 polymorphic fragments. Average genetic distance (AGD) between the 15accessions was 58.7% (32-88%). AGD and range of genetic distance among accessions from Cameroun,Nigeria and Gabon were 62% (53-76%), 52% (32.3 – 84.8%) and 50% (45-53%), respectively, indicatingmore genetic diversity in Cameroun than Nigeria and Gabon. The unweighted pair-group method of thearithmetic average (UPGMA) and principal coordinate analysis (PCO) showed a clear distinctionbetween the Gabon and Nigeria accessions into two separate clusters, with accessions from Camerounoverlapping them. Principal coordinate analysis (PCO) indicated a closer relationship betweenaccessions from Cameroun and Gabon. In general the Cameroun germplasm appears to be a bridgebetween the genetically isolated Nigeria and Gabon accessions. This overlap of Gabon and Nigerianaccessions by the accessions from Cameroun may be an indication that Cameroun is the center ofdiversity of I. gabonensis and also the primary source of original materials grown in the other countries.More collection in Cameroun is necessary to ensure the optimum collection and preservation of theexisting genetic diversity in I. gabonensis.
A decision support tool for propagating miombo indigenous fruit trees of southern Africa
Indigenous fruit trees (IFTs) contribute to the livelihoods of rural households as sources of food, income and medicine. Conservation and domestication of IFTs involve germplasm selection, collection, multiplication and evaluation. In addition, biodiversity and genetic improvements have been realized through propagation. However, there are numerous challenges when propagating indigenous trees and the choice of appropriate propagation techniques determines the success of domestication programme. In this paper we synthesize different propagation methods used for indigenous fruit trees, and propose a decision support tool based on desirable attributes of individual IFT, technical requirements, expertise of the propagators and relative cost of implementing the technology in addition to field performance and tree management. Depending on circumstances, this decision support tool can be used to quickly choose a propagation method for a given fruit tree so as to maximize on germplasm collection, multiplication and evaluation without compromising field performance and management of the fruit trees.
Genetic diversity and gene flow revealed by microsatellite DNA markers in some accessions of African Plum (Dacryodes edulis) in Cameroon
Dacryodes edulis is a multipurpose tree integrated in the cropping system of Central African region still dominated by subsistence agriculture. Some populations grown are wild which can provide information on the domestication process, and could also represent a potential source of gene ow. Leaves samples for DNA extraction were collected from wild forms in Mbakwa supe region and from cultivated forms in Yaounde and Santchou region. Six microsatellites DNA markers were employed in genotyping to analyze population structure and gene flow. Amplification rate was high and genotyping revealed high level of genetic variation. The overall polymorphic level at the six loci was also high with average expected heterozygosity of 0.53; polymorphism of 0.46; mean allelic diversity of 0.5 and mean allele number of 8.33. There were no clear differences with only 1% variation among the three populations and 6% variation among individuals within populations. In contrast, the rate of heterozygosis was high in all the three populations. Both the number of migrant per generation (Nm=20) and the Wright’s F-statistics (FST=0.012) suggest that there was substantial gene ow among the populations. These findings indicate that D. edulis possess a great potential of pollen dispersal and dominant cross-pollination within populations. Most of the loci with private alleles (45%) were found in wild individuals which could be a source of pollen for crossing their cultivated relatives.
Analysis of the impact of domestication of Warburgia ugandensis (Sprague) on its genetic diversity based on amplified fragment length polymorphism
Warburgia ugandensis Sprague (Canellaceae) occurs in East and Central Africa and is an important multipurpose tree species. Over-exploitation of natural forests for medicinal purposes and clearance for farming threaten the species survival. Cultivation of the tree species would ensure sustainable medicinal source and its conservation. However, on-farm genetic diversity of the species is currently unknown. The genetic diversity of the on-farm W. ugandensis populations and their proximate natural populations were analyzed using the amplified fragment length polymorphism (AFLP). Four primer combinations produced a total of 223 polymorphic bands. Both the natural and on-farm populations had high genetic diversity ranging from H = 0.2892 to H = 0.1278. Principal co-ordinates analysis and dendrogram separated the ten populations into two major groups corresponding to Kenyan and Tanzanian populations, respectively. Ugandan populations were shared between the two major groups; this is probably because Uganda is believed to be the centre of diversity for W. ugandensis. Close genetic relationships between the on-farm and their proximate natural population were revealed. Analysis of molecular variance (AMOVA) revealed that a total of 54% AFLP variation resided within populations with 46% reside among populations. The high genetic diversity of W. ugandensis on-farm populations could be useful in germplasm collection and conservation strategies.