The domestication of indigenous tropical trees starts with the identification of germplasm collection sites. Collecting from a wide genetic base enhances the ecological quality of each collection activity. Determining species occurrence, potential collection sites, and distribution by relying too heavily on published information based on their ‘biophysical limits’ has shown itself to be full of practical challenges. Within the tree domestication process, the identification and illustration of the geographic re-distribution of high-value tropical trees through their cultivation by farmers, enriches the process of tree germplasm collection. This paper draws parallels between tree cultivation by farmers in Cameroon and the inadvertent testing of the trees in niches and habitats often different from the natural homes of the species. By forcing species to adapt in regions other than those in which they might have been naturally selected, farmers ‘force’ certain genetic attributes of individual trees, necessary for their survival, to be expressed in one form of adaptation or another. The surviving trees may subsequently constitute unique stands with peculiar genetic and/or phenotypic characteristics. As these resilient man-made stands spread across broad geographical areas, mapping them becomes equivalent to recording an expression of that ‘resilience’ factor in the species. Recording these sites with the rest of its natural range of occurrence is thus equal to mapping the species’ diversity or its ‘domestication range’. The methodology used in this study utilized published biophysical information on vegetation, precipitation, temperature and altitude, as well as geographic data on germplasm collection, cultivation sites and natural stands. These data layers were then used to suggest zones of possible occurrence and distribution. Field collections and survey activities were later used to verify incidence and cultivation sites of four sample tropical tree species, in Cameroon: Irvingia gabonensis, Cola nitida, Prunus africana, and Dacryodes edulis.
Tag: germplasms
Intensifying vegetable production in smallholder agroforestry systems in West Java
Most smallholder farmers in Indonesia cultivate both annual and perennial crops on farms of limited size, frequently 1 ha or less. Traditionally, these systems evolved to produce agricultural and tree products for home consumption, with the surplus being sold locally. The development of infrastructure and market economies has opened commercial opportunities for smallholder farmers. However, many smallholders still face challenges related to crop production and marketing: landholdings do not reflect economies of scale; suboptimal management practices produce commodities that do not meet market specifications; and farmers have limited understanding of market information and marketing channels. Additionally, farmers lack access to professional assistance that could enable them to enhance their production and marketing capacity. Working with communities in West Java, the authors implemented a number of studies to identify how vegetable production could be intensified in smallholder agroforestry systems where additional land for agricultural expansion did not exist. Baseline studies and rapid market appraisal were conducted to identify existing conditions and possible opportunities. Focus group discussions were held to identify smallholders’ and traders’ interest in expanding smallholder vegetable production and marketing. Understory vegetable production trials were conducted under three light intensity levels representative of common agroforestry systems. A cross-visit was held to provide exposure and intensive capacity building to smallholders regarding market-oriented production of select vegetable commodities. A consumer preference study was implemented to inform smallholders and traders regarding market prospects. Findings indicate that opportunities exist for smallholders to intensify production and marketing of vegetables in their existing agroforestry systems. However, to take full advantage of those opportunities, smallholder farmers would require technical, marketing, and material assistance
Are homegarden ecosystems resilient to climate change? An analysis of the adaptation strategies of homegardeners in Sri Lanka
Homegarden ecosystems are considered to be resilient to climatic changes partly due to the use of efficient and effective adaptation strategies by the homegardeners. This study documented the strategies adopted by homegardeners in Sri Lanka and investigated the determinants of the choice of such strategies. Data gathered from household surveys conducted in three selected locations were analysed to achieve the study objectives. About 52% of the homegardeners in all locations were found to be small-scale farmers (<0.5 ha) engaged in semi-subsistence farming over a long period of time. The majority (85%) of them have had their education only up to the primary level. Among the homegardeners, more than 63% in Keeriyagaswewa, 54% in Pethiyagoda and 90% in Siwalakulama have not made any significant changes to the plant, tree and animal composition of homegardens over the past 20 years. A number of adaptation strategies have been used by the homegardeners enabling them to maintain the diversity in the homegarden ecosystem. The changes in planting dates (37%), agronomic practices (39%), use of soil and water conservation measures (41%) and technology (55%) such as use of new varieties and irrigation equipments were the most commonly used adaptation strategies. A considerable variation in the type of adaptation strategies across the households was noted. The results of the probit analysis indicated that the type of employment, age, sex, education level of household head, experience in farming, homegarden size, diversity of homegardens measured by the Shannon Weiner Index (SWI), and perceptions towards climate change significantly influence the decision to adopt a given strategy. The development programs to promote adaptation to climate changes in homegardens should hence be designed taking the above determinants into consideration.
Tree Seed Suppliers Directory
This directory is intended to contribute to the informed use of tree germplasm, which is an essential component of sustainable forestry and agroforestry practices, and promote wider use of quality germplasm.
Erratum to: Association mapping of North American spring wheat breeding germplasm reveals loci conferring resistance to Ug99 and other African stem rust races
Upon publication of this article [1] it was noticed that Tables Two-Seven (Tables 1, 2, 3, 4, 5 and 6 here) were formatted incorrectly. The Tables have now been updated in the original article
Northern leaf blight response of elite maize inbred lines adapted to the mid-altitude sub-humid tropics
Productivity of maize (Zea mays L.) is curtailed by a number of stress factors, predominantly by diseases and insect pests. The Northern leaf blight disease of maize caused by Exserohilum turcicum (Pass.) Leonard and Suggs inflict significant yield losses in the humid tropical regions. The objectives of this study were to determine the leaf blight response of 50 elite maize inbred lines developed for the mid-altitude, sub-humid tropics and to select promising parents for resistance breeding. Inbred lines were evaluated in the feld using a 5 × 10 alpha lattice design with three replications. Plants were artificially inoculated at the 4-6 leaf stages during 2011 and 2012. Data on disease severity and incidence, AUDPC and yields were recorded. Inbred lines had significant differences for E. turcicum reactions, and were classified into resistant, intermediate or susceptible categories. The mean disease severity ranged from 2.04% for the inbred line 136-a to 3.25% (Kuleni-C1-101-1-1-1). The upper leaf area infection of inbred lines 143-5-I and 136-a was 3.3%, while the line Kuleni-C1-101-1-1-1 displayed 100% infection. Further, 136-a developed the lowest AUDPC score at 238, whereas Kuleni-C1-101-1-1-1 had the maximum at 700. Overall, inbred lines CML202, 144-7-b, 139-5-j, 136-a, 30H83-7-1-1-1-2-1, ILoo’E-1-9-1-1-1-1-1 and 142-1-e, were identified as promising sources of resistance against E. turcicum. The selected elite inbred lines would be recommended for use in general varietal development, disease management and to enhance maize productivity, in the mid-altitude sub-humid tropics. © 2016 Akadémiai Kiadó, Budapest.
Tracking the spillover of introduced technologies: The case of improved banana (Musa spp) in Northeast Tanzania
This paper reviews a methodology for tracking the pattern and extent of spillover of introduced technologies, using improved banana (Musa spp) germplasm in Lushoto, Northeast Tanzania, as a case study. Such tracking is important in understanding the factors responsible for the spread of technologies and the accompanying farmer innovations. Spillover of technologies, as used here, refers to the spontaneous flow, or spread, of technologies between farmers using their social networks without external interference. Formal surveys, farmers’ records and focus group discussions were used to establish the path taken and distance covered by the technology, the barriers encountered, and modifications made by farmers on the technology. Lessons derived from the study show that farmers made different modifications to the introduced technologies in order to fit them into the existing farming systems. The pattern of spillover is very much related to existing social networks in the community. Kin (nuclear and extended families) accounted for 53% of the spillover of improved banana germplasm, compared to 47% in non-kin (friends and neighbor) social networks. Improved banana suckers, introduced in Lushoto, were found as far as in Dar es Salaam; more than 300 km away. Gender bias was exhibited in the spontaneous sharing of cash generating technologies (cash crops) like banana, with exchanges between women being negligible.
Morphological characterization of Soursop (Annona muricata L.) germplasm in Sri Lanka
Annona muricata L. is an underutilized fruit tree species in Sri Lanka, which is mostly confined to homegardens. Despite the importance of A. muricata, collection, characterization and improvement of its germplasm is limited in Sri Lanka, hence hindered its effective conservation and utilization. Therefore, the objective of this research was to identify morphological variation of A. muricata populations in Sri Lanka. Multistage Sampling Survey was conducted in homegardens of Anuradhapura, Polonnaruwa and Hambantota dictricts in the Dry zone, Puttalama and Kurunagala districts in the AIntermediate zone, and Kalutara and Gampaha districts in the Wet zone. Random representative samples were also collected from existing germplasm collections at three national research centers. Morphological variation of A. muricata were observed on total of 315 samples collected from seven districts of three climatic zones and 133 samples collected from germplasm collections at three national research centers. Forty five morphological characters were recorded from 448 accesions and subjected to Principal Component Analysis (PCA) and Factor Analysis (FA), followed by Cluster Analysis. A dendrogram of evaluated characters showed nine distinguished clusters. Implications of findings are discussed in relation to utilization and conservation.
Productivity of Acacia angustissima accessions at two sites in the subtropics
Low leaf biomass yields coupled with small land sizes are some of the major constraints faced by smallholder farmers that grow protein-rich fodder trees and shrubs. Given these challenges, availability of highly productive seed sources would be important to enable farmers to produce leaf fodder in sufficient quantities. 14 accessions of Acacia angustissima were evaluated for leaf, wood and total biomass production at two subtropical sites with uni-modal rainfall in Zimbabwe, with the objective of identifying high leaf biomass yielding accessions. There were up to fourfold difference in biomass yield between the accessions. Leaf dry matter yield ranged from 1.65 to 8.81 Mg ha-1 and 3.7 to 12.4 Mg ha-1 for wood biomass at the higher altitude site (1530 m a.s.l.) but were much lower at 1272 m a.s.l. where they ranged between 0.37 and 4.88 Mg ha-1 for leaf and 0.4 and 7.2 Mg ha-1 for wood. The most productive accessions for leaf biomass were 16231 and 18579 at the higher altitude site, while 18586 and 18501 had the highest yields at the lower altitude. Although no one accession was consistently high yielding across the two sites, the least productive accessions were consistently poor at both sites. The advantage of using selected superior accessions over the unselect bulk seed was up to 85%. These findings underscore the need to promote the use of only high yielding accessions rather than unselect bulk seed. This study identified new, more productive accessions of A. angustissima that potentially widens the genetic base of the germplasm assembled in Zimbabwe.
Estimation of heritability and genetic gain in height growth in Ceiba pentandra
Ceiba pentandra (L.) has been selected for plantation establishment in Ghana under the National Forest Plantation Development Programme of Ghana (NFPDP). This has led to a rise in demand for its seedlings for large scale commercial plantation establishments with seed of C. pentandra being collected from the wild and used to raise seedlings to meet the demands of the programme. The primary purpose of most of these plantations is timber with height growth as one of the key economic traits. However, there is relatively inefficient information available on the heritability and genetic gain in height growth in C. pentandra based on which selection and subsequent breeding could be made. This poses a major challenge to the production of new cultivars for the forestry industry of Ghana. The current study looked at the estimation of narrow sense heritability (h2) and genetic gain in height growth in C. pentandra using 37 accessions from Ghana. Narrow sense heritability was 0.56 and genetic gain in height ranged from -52.82 to 37.30 cm/yr. Twenty-two (22) accessions (59.46%) had mean height increment above the overall mean performance and were recommended for conservation as seed trees. The results were discussed in relation with the conservation of C. pentandra genetic resources and the potential of accessions for high genetic gains.