Effect of staking and non-staking systems on disease severity, yield and quality attributes of yams (Dioscorea alata)

Aims: The aim of this study was to evaluate the effect of staking and non-staking systems on disease severity, yield and quality attributes of yams. Methodology: High costs and lack of planting materials, labour, staking and inappropriate knowledge on production techniques are major constraints of yam production in Sierra Leone. A total of seven promising hybrid genotypes of yams from International Institute of Tropical Agriculture and one local cultivar, Pulli, were evaluated for yield, reaction to local pest and disease and desirable market traits during 2011 and 2012 in three agro-ecological zones of Sierra Leone. The experiment was laid out in randomized complete block replicated thrice at the experimental sites of the Njala Agricultural Research Centre. Results: Results revealed higher disease pressure in non-staked plots compared to staked plots. Fresh tuber yields were significantly higher in staked plots than the non-staked plots. Five genotypes with yields ranging between 11.8 and 14.7 t.ha-1 significantly out-yielded Pulli (9.1 t.ha-1) in the staked plots, while only genotype TDa 02/00012 (11.9 t.ha-1) significantly out-yielded Pulli (7.1 t.ha-1) in the non-staked plots. Farmers’ preferences for all genotypes were similar to that of the local cultivar. Staking contributed 30.5% mean yield increase compared to non-staking. Makeni had the highest percent mean yield increase due to staking (38.5%) compared to Njala (29.7%) and Kenema (26.4%). Conclusion: Staking is beneficial in yam production contributing an average of 28.2% more fresh tuber yields than non-staking. Genotypes in staking system were more tolerant to in-field local diseases, thereby significantly out-yielding those in non-staking system. Genotypes TDa 98/01174, TDa 98/01176, TDa 02/00012, TDa 98/01168 and TDa 00/00194 had stable resistance to in-field diseases in the staking system and desired food quality traits compared to the check variety, Pulli. Findings have good implications for multiple disease resistance breeding for various production systems as the different genes controlling these traits could be pyramided into an ideotype. Similar technique could be used to breed for yield and other desired food quality traits

Status and diversity of the cassava Mosaic disease causal agents in Sierra Leone

Cassava is the most important root and tuber crop in Sierra Leone. Its low yield can be attributed to several production-limiting factors including cassava mosaic disease (CMD). This study examined in a much wider scope the diversity, prevalence, distribution, incidence and level of severity of the CMD within the cassava farming communities across major agro ecologies in Sierra Leone. A survey was conducted October, 2010. Field assessment was also conducted on farms evaluated. Data was collected on the spot and complimented with group discussions and interviews. Field coordinates were determined using a global positioning system (GPS) recorder. This study showed a countrywide prevalence of 85.2% out of 156 sites visited using GPS mapping. The rain forest ecology had the highest prevalence of 97.2% while the coastal plain had the lowest disease prevalence. Incidence of CMD per district was generally high. Tonkolili district recorded the highest incidence of 99.2% followed by Kailahum and Pujehun. Bonthe district had the lowest severity score, while pujehun district had the highest severity score. Difference in CMD infection was also observed in terms of agro-ecology. Test using polymerase chain reaction (PCR) detected African cassava mosaic virus (ACMV) and also for the first time the East African cassava mosaic virus (EACMV) in two locations in the Moyamba district, southern Sierra Leone. The result from this study indicates the need for an increased adoption of CMD resistant cassava genotypes that are high yielding, has good cooking quality and with the ability to replace the local choice variety without significantly altering the cultural and aesthetic quality of the generally accepted local cultivar

Breeding for blast resistance in rice in West Africa

Rice is grown in an area of 4.3 million ha in 17 WARDA member countries of West Africa (FAO, 1994). The total annual production is 7.4 million tons of paddy with an average yield of 1.7 tons ha−1, which is the lowest compared to other rice growing regions of world.The rice import in WARDA member states in 1995 was 2.43 million tons with a value of 684 million US$ (WARDA Data Base, 1998). The average yield in the region is low due to presence of many biophysical constraints, which reduces the yield potential of the varieties. Rice blast (Pyricularia grisea) is one of the major biotic constraints affecting rice production. It is a widespread and most serious disease in all the rice growing ecologies (Awoderu, 1974; Bidaux, 1978; John et al., 1985; Fomba and Taylor, 1994). Seedling blast occurs in nursery stage in transplanted rice, leaf blasts under direct seeded uplands and rainfed lowlands, and panicle blasts in all the ecologies

Current status of root and tuber crops improvement, production and utilization in Sierra Leone

Cassava (Manihot esculenta Crantz) is the second most important food crop after rice, the staple in Sierra Leone; it is also the most important root and tuber crop. It is followed by sweet potato (Ipomoea batatas L.), yam (Dioscorea spp.), which forms part of the traditional farming system and has only recently been included in the research agenda of NARC/SLARI and potato (Solanum tuberosum L) aka “Irish” potato in Sierra Leone, an introduced crop from neighbouring Republic of Guinea. Genetic improvement of the above crops is mainly through introduction of exotic germplasm from the International Institute of Tropical Agriculture (IITA) at Ibadan, Nigeria; and screening, selection and advancement of promising lines in a participatory manner with farmers and other stakeholders in the crop development process. Breeding objectives of the above crops are aimed at addressing the devastating problem of pests and diseases prevalent in Sierra Leone, cassava mosaic disease (CMD), cassava bacterial blight (CBB), green mite, mealy bug and grasshoppers; sweet potato virus x and scab, and late blight of potato), yield and quality for the various desirable traits of eating, processing and potential industrial uses. Several genotypes of cassava have been released in the recent past (SLICASS 1-6) with yield range of 25-35 mt/ha whilst new and more nutrient-rich genotypes including yellow rooted ones with yield range of 40-50 mt/ha are in the pipeline for release. The yield ranges of sweet potato, yam and potato are 6-10 mt/ha, 10-27 mt/ha and 2-4 mt/ha, respectively. Four potato varieties (SLIPOT 1-4) were recently released to the farming population of Sierra Leone. The current status of cassava, sweet potato (including recent and more nutritious, âcarotene genotypes), yam and potato breeding activities at NARC/SLARI, Sierra Leone is summarized and presented. Yam and potato improvement is new but significant strides have already been made in identifying promising lines of the former with the desirable traits or qualities that are acceptable to both farmers and consumers alike in the country. Production of cassava has increased more than three folds since the end of the civil war in 2002, during which period it served as the most easily cultivated, accessible and affordable food crop, along with sweet potato to the majority of the then internally displaced population (IDP). Recent trends in production of these two crops are also given. Cassava transformation into many useful food products, especially gari, fufu and high quality cassava flour (HQCF) is receiving tremendous boost in many parts of the country by both regional and national projects (CFC/IITA/SLARI) Cassava Value Addition, USAID/IITA-Sierra Leone Unleashing the Power of Cassava in Africa (UpoCA), AfDB/FARA/CORAF/WECARD/ SLARI Promotion of Science and Technology for Agricultural Development (PSTAD) in Africa Project (Dissemination of New Agricultural Technologies in Africa (DONATA) and Regional Agricultural Information Learning Systems (RAILS), Non-Governmental Organizations (NGOs) and the private sector. Strides made in that direction are also summarized and presented. On a lesser scale, processing of sweet potato into more durable and useful by-products such as flour is beginning to receive the necessary attention by scientists at NARC/SLARI, and Njala University (NU), Sierra Leone and the Federal University of Agriculture at Abeokuta (UNAAB) and Association of African Universities (AAU) Regional Food Developers Initiative (FDI) Project, Nigeria. This will hopefully prevent market glut and improve the livelihood of root and tuber crops farmers with a consequent reduction in poverty

Current Status of Root and Tuber Crops Improvement, Production and Utilization in Sierra Leone

Cassava (Manihot esculenta Crantz) is the second most important food crop after rice, the staple in Sierra Leone; it is also the most important root and tuber crop. It is followed by sweet potato (Ipomoea batatas L.), yam (Dioscorea spp.), which forms part of the traditional farming system and has only recently been included in the research agenda of NARC/SLARI and potato (Solanum tuberosum L) aka “Irish” potato in Sierra Leone, an introduced crop from neighbouring Republic of Guinea. Genetic improvement of the above crops is mainly through introduction of exotic germplasm from the International Institute of Tropical Agriculture (IITA) at Ibadan, Nigeria; and screening, selection and advancement of promising lines in a participatory manner with farmers and other stakeholders in the crop development process. Breeding objectives of the above crops are aimed at addressing the devastating problem of pests and diseases prevalent in Sierra Leone, cassava mosaic disease (CMD), cassava bacterial blight (CBB), green mite, mealy bug and grasshoppers; sweet potato virus x and scab, and late blight of potato), yield and quality for the various desirable traits of eating, processing and potential industrial uses. Several genotypes of cassava have been released in the recent past (SLICASS 1-6) with yield range of 25-35 mt/ha whilst new and more nutrient-rich genotypes including yellow rooted ones with yield range of 40-50 mt/ha are in the pipeline for release. The yield ranges of sweet potato, yam and potato are 6-10 mt/ha, 10-27 mt/ha and 2-4 mt/ha, respectively. Four potato varieties (SLIPOT 1-4) were recently released to the farming population of Sierra Leone. The current status of cassava, sweet potato (including recent and more nutritious, âcarotene genotypes), yam and potato breeding activities at NARC/SLARI, Sierra Leone is summarized and presented. Yam and potato improvement is new but significant strides have already been made in identifying promising lines of the former with the desirable traits or qualities that are acceptable to both farmers and consumers alike in the country. Production of cassava has increased more than three folds since the end of the civil war in 2002, during which period it served as the most easily cultivated, accessible and affordable food crop, along with sweet potato to the majority of the then internally displaced population (IDP). Recent trends in production of these two crops are also given. Cassava transformation into many useful food products, especially gari, fufu and high quality cassava flour (HQCF) is receiving tremendous boost in many parts of the country by both regional and national projects (CFC/IITA/SLARI) Cassava Value Addition, USAID/IITA-Sierra Leone Unleashing the Power of Cassava in Africa (UpoCA), AfDB/FARA/CORAF/WECARD/ SLARI Promotion of Science and Technology for Agricultural Development (PSTAD) in Africa Project (Dissemination of New Agricultural Technologies in Africa (DONATA) and Regional Agricultural Information Learning Systems (RAILS), Non-Governmental Organizations (NGOs) and the private sector. Strides made in that direction are also summarized and presented. On a lesser scale, processing of sweet potato into more durable and useful by-products such as flour is beginning to receive the necessary attention by scientists at NARC/SLARI, and Njala University (NU), Sierra Leone and the Federal University of Agriculture at Abeokuta (UNAAB) and Association of African Universities (AAU) Regional Food Developers Initiative (FDI) Project, Nigeria. This will hopefully prevent market glut and improve the livelihood of root and tuber crops farmers with a consequent reduction in poverty