Use of synthetic pesticides to manage crop pests has had a toll on human health, environmental safety and farmer’s income creating a need for alternative crop protection strategies. Botanical pesticides have been rep...Use of synthetic pesticides to manage crop pests has had a toll on human health, environmental safety and farmer’s income creating a need for alternative crop protection strategies. Botanical pesticides have been reported to be effective in managing crop pests, and a number of them have been formulated and commercialized. This study was conducted in North-Eastern Tanzania to establish the pesticidal and medicinal value of turmeric (Curcuma longa) and ginger (Zingiber officinale). Purposive sampling was adopted to select and interview 167 respondents drawn from farmers, traders, pharmaceutical shops, agro-shop operators and consumers of turmeric and ginger. Ginger and turmeric rhizomes were also collected for extraction, antifungal assay and biochemical analysis. Results showed that majority of the respondents were aware of the medicinal value of ginger and turmeric, with 59.5% having used the plants to treat respiratory related infections and healing skin surface and internal wounds. About 14% of farmers were aware of and had used aqueous botanical preparations from neem, moringa and Tephrosia to manage insect pests. Only 2.7% of farmers had used ginger powder as a protective insecticide on stored grains. Ginger and turmeric rhizome extracts showed high antifungal activity against Pythium (83% - 95%), Fusarium oxysporum f. sp. lycopersici (34% - 52%) and Alternaria solani (38% - 53%). A GC-MS analysis of ginger and turmeric extracts showed presence of α-zingiberene, β-sesquiphellandrene, α-farnesene, ar-curcumene, α-copaene, ar-tumerone and curlone. This study recommends that ginger and turmeric extracts be considered for development of a botanical pesticide and especially for management of damping off diseases.展开更多
A substantial body of research has been conducted with the objective of enhancing the understanding of Non-Timber Forest Products (NTFP) in Central Africa. A significant proportion of the studies focus on medicinal pl...A substantial body of research has been conducted with the objective of enhancing the understanding of Non-Timber Forest Products (NTFP) in Central Africa. A significant proportion of the studies focus on medicinal plants, in contrast to those that examine food products. Nevertheless, studies on edible wild mushrooms as NTFPs and cultivated mushrooms, on their economic potential and value chains in the Great Lakes Region, remain scarce and largely absent for some NTFPs. In light of the aforementioned considerations, the present study aims to examine the economic potential and value chain of the production sector of wild edible mushrooms (WEM) and cultivated mushrooms (CM) within the Virunga National Park (PNVi) and its surrounding areas in North Kivu, Democratic Republic of the Congo (DRC). To this end, a sample of 432 respondents was selected, distributed equitably among the actors of the Goma-Kitshanga-Mweso value chain, the Goma-Rutshuru chain, the Beni-Mutwanga chain, and the Beni-Mangina chain. A digital questionnaire consisting of open and closed questions was administered, and observations were carried out concurrently. The quantities of mushrooms sold were weighed and photographed. The results demonstrated that, when the eight-month fruiting period of wild and cultivated mushrooms was considered as a single year for all actors within the value chain, a picker could sell 6.1 kg at $2 and earn $12. A seller could sell 16 kg at $4 and earn $64, while a grower could sell 502 kg at $3 and earn $1506. Consequently, the CM grower generates a significantly higher profit than other participants in the value chain, despite the expenses he incurs. Ultimately, the domestication of WEM, highly prized by the local population of the Virunga National Park, has the potential to enhance their household incomes, as evidenced by the findings of this study.展开更多
The parasitic weed Striga poses a serious threat to cereal production in sub-Saharan Africa. For many years, technological packages for the control of this weed were proposed and implemented on farmers＇ fields. A sur...The parasitic weed Striga poses a serious threat to cereal production in sub-Saharan Africa. For many years, technological packages for the control of this weed were proposed and implemented on farmers＇ fields. A survey was carried out in farmers＇ fields in 2010/201l cropping season in selected dryland areas of Tanzania to： （a） determine the Striga plant counts, number of capsules/Striga plant and agronomic practices used by farmers to control Striga; and （b） evaluate the relationship between Striga reproduction, soil chemical characteristics and agronomic practices. Soil samples at 0-20 cm depth were collected from 20 different farmers＇ fields. The soil samples were analyzed for pH, organic carbon, N, P and K. Results showed that there was low adoption of recommended Striga control methods. Regression analysis of agronomic practices and soil chemical characteristics revealed a positive improvement of soil N and organic carbon and reduction of soil P and K content as one shifted from sole planting to intercropping. The results showed that potassium was highly positively related to number of capsules/Striga plant. There was a reduction in the number of capsules/plant as one moved from sole planting to intercropping. Based on these findings, K in the Striga infested in soils positively influenced Striga reproduction and seed bank replenishment, hence high soil K levels may lead to high Striga incidence.展开更多
The stability of soybean genotypes is very important in breeding programs for not only the evaluation, selection, and production of cultivars but also the establishment of parameters required for the classification of...The stability of soybean genotypes is very important in breeding programs for not only the evaluation, selection, and production of cultivars but also the establishment of parameters required for the classification of genotypes into relative maturity groups (RMG). The aim of this study was to define stable genotypes for traits, such as days to flowering, days to maturity, and length of the reproductive period, and to classify them into RMG. For this purpose, 20 commercial soybean cultivars were evaluated in 12 environments distributed in the major producing regions of Brazil. Assessments according to the Eberhart and Russell method and the additive main effects and multiplicative interaction (AMMI) method were effective in the identification of stable genotypes and their classification into RMG. These methods can also be used collectively for this purpose. Our results showed that the AMMI method led to a better interpretation of genotype-environment interactions. Thus, RMG obtained on the basis of stable genotypes represented a good estimate of the relative maturity of soybean crops throughout Brazil. *Corresponding author.展开更多
Laboratory and green house experiments were carried out to evaluate the efficacy of fungicides, biological agents and host resistance in managing FHB and the associated T-2 toxin. In vitro activity of fungicides and a...Laboratory and green house experiments were carried out to evaluate the efficacy of fungicides, biological agents and host resistance in managing FHB and the associated T-2 toxin. In vitro activity of fungicides and antagonists was determined by paired culture method. Effect of microbial agents on FHB severity and mycotoxin content was determined by co-inoculating F. graminearum and F. poae with Alternaria spp., Epicoccum spp. and Trichoderma spp. Fungicides Pearl? (500 g/L carbendazim), Cotaf? (50 g/L hexaconacole), Thiovit? (micronised sulphur 80% w/w) and Folicur? (430 g/L tebuconazole) were the standard checks. Host resistance was determined by inoculating F. poae and F. graminearum to four wheat cultivars and fifteen lines in pot ex-periments. Fungicides resulted in 100% inhibition of pathogen radial growth in in vitro while microbial agents suppressed pathogen growth by up to 53%. Thiovit? and Trichoderma were the most effective in reducing FHB severity in green house pot experiments. The wheat cultivars and lines varied in susceptibility with cultivar Njoro BW II showing least susceptibility while line R1104, cv. Mbuni and cv. KIBIS were most susceptible. All the wheat cultivars and lines accumulated T-2 toxin by up to 5 to 28 μg/kg. The results indicated that neither fungicides nor antagonists can solely be relied on in managing FHB and toxin accumulation. Therefore, integration of biocontrol agents, fungicides and further breeding efforts to improve lines and cultivars with promising resistance to FHB and T2-toxin contamina-tion is recommended.展开更多
In Uganda, grain amaranth is relatively new and has generally not been considered as an important crop compared to other grain crops and legumes. This study was therefore conducted to determine factors affecting adopt...In Uganda, grain amaranth is relatively new and has generally not been considered as an important crop compared to other grain crops and legumes. This study was therefore conducted to determine factors affecting adoption of grain amaranth growing, factors affecting production, and economic returns on investment of its production. The study was carried out in Kamuli district where a total of 174 grain amaranth farmers and 90 non-grain amaranth farmers were randomly selected and interviewed. Using descriptive statistics, regression analysis （logit model and a Cobb-Douglas type production function） and profitability ratios, it was found that grain amaranth is produced on a small scale and yields are low. Farmer adoption of the crop was favoured by age, gender （female）, education of the farmer, and source of income. The output was positively affected by the amount of labour and manure used in production, while a negative relationship existed between output and male farmers. The crop was most viable under small acreages （0.02-0.04 ha） with positive returns to investment of 0.016. Its production should therefore be encouraged because of its income generation potential and since it requires small land.展开更多
Survey covering 120 wheat fields was conducted in three wheat-growing districts of Kenya during the 2008 cropping season to determine the incidence of Fusarium head blight (FHB) and T2-toxin contamination in grain. FH...Survey covering 120 wheat fields was conducted in three wheat-growing districts of Kenya during the 2008 cropping season to determine the incidence of Fusarium head blight (FHB) and T2-toxin contamination in grain. FHB incidence was determined as the number of blighted ears per 10m2. Information gathered included wheat production practices, rainfall and temperature data. Fungal pathogens were isolated from wheat stems, heads, straw, grains and soil and identified based on cultural and morphological characteristics. Wheat grain samples were analyzed for T2-toxin by competitive Enzyme Linked Immunosorbent Assay (ELISA). High FHB incidences of up to 88% were recorded. Fungal genera isolated included Fusarium, Epicoccum, Trichoderma, Alternaria and Penicilium. Wheat plant parts with high infection with Alternaria and Epicoccum had corresponding low levels of Fusarium spp. Whereas Fusarium spp. were the most common fungal pathogens in stems, heads and soil, Epicoccum was frequently isolated from straw and grains. Fusarium speciesisolated included F. poae, F. graminearum, F. stilboides, F. verticilloides, F. fusarioides, F. tricinctum and F. heterosporum with F. poae and F. graminearum accounting for approximately 40% of all Fusarium infections. T-2 toxin was detected in all the grain samples and varied from 3 to 22 ppb. The study showed that FHB and T2-toxin are prevalent in the study districts and the high diversity of Fusarium species implies a challenge in FHB management as well as a risk of chronic T2-toxin exposure to humans and livestock.展开更多
The production of maize is constrained by parasitic weeds, particularly Striga. A study was carried out to document farmers＇ knowledge, attitude and practices on Striga control among smallholder farmers across three ...The production of maize is constrained by parasitic weeds, particularly Striga. A study was carried out to document farmers＇ knowledge, attitude and practices on Striga control among smallholder farmers across three districts： Kisumu West, Busia and Teso South of Western Kenya. A multistage sampling technique was used to select the locations and farmers to be interviewed. A semi structured, open and closed ended questionnaire was administered leading to field experiment. Besides village meetings （39.2%）, farmers got informed on farming methods under Striga weed farms and its control technologies through neighbours （2.5%）, workshops and trainings （5.0%）, field schools （3.7%）, media （7.5%） and extension agents （10.8%）. The attitudes of farmers towards Striga control varied but frequently cited： long term viability of the Striga seed （12.5%）, difficult to control sharing of farm tools （10.8%）, expensive technologies （13.3%）, lack of adequate information （18.3%）, labour intensive （15.0%）, large farms for use of push and pull technology （1.7%） and time consuming （12.5%）. Framers used various Striga control practices but traditional methods （25%） were among the most used （25%）. Concerted effort involving researchers, extension agents and private sector are, therefore, required for wide scale dissemination and adoption of the existing modem control technologies.展开更多
Currently the soybean crop is affected by the white mold (Sclerotinia sclerotiorum). The disease can reduce the crop yield and quality and decrease the prices of agricultural lands. The aim of the current research was...Currently the soybean crop is affected by the white mold (Sclerotinia sclerotiorum). The disease can reduce the crop yield and quality and decrease the prices of agricultural lands. The aim of the current research was to assess epidemiology of white mold on soybean crop grown at Arapoti, PR, Brazil, utilizing data related to agricultural practices and local meteorological factors. The experiment was conducted in a naturally infested area. The soybean crop was sown on October 18th, 2011. The experimental design adopted herein was a randomized block in a factorial combination with 4 row spacings (0.35, 0.45, 0.60, 0.75 m) and 4 plant populations (150, 200, 250, 300 thousand plants per hectare) and 4 replications. The temporal analysis of the epidemic was evaluated using mathematical models, such as Logistics, Monomolecular and Gompertz, in order to determine the best model that described the progress of the disease as a function of local meteorological elements. For the incidence data it has been shown that both logistic and monomolecular models were those that were best fitted to the experimental data. For severity, the best model related to the experimental data was the logistic one. Either for incidence or for severity, air temperature was considered to be the environmental factor most affecting the progress of the disease. The variability in the apparent infection rates of white mold on soybean was not affected by different row spacings and plant populations;therefore, suggesting that macroclimatic variations prevailed in such a fashion to mitigate the effect of cultural practices adopted in the field.展开更多
Biopesticides are derivatives of plants, microorganisms and insects. Substances from plants and animals have been used to manage diseases in crops, animals and humans. Reliance on nature to heal nature is a practise f...Biopesticides are derivatives of plants, microorganisms and insects. Substances from plants and animals have been used to manage diseases in crops, animals and humans. Reliance on nature to heal nature is a practise for many people around the world. Use of natural products was overtaken by synthetic chemicals due to their efficacy, reliability and quick knock down effect. However, synthetic pesticides have become a health hazards for humans and environment due to their toxicity and pollution. Biopesticides are potential alternatives to synthetic pesticides. Sources of biopesticides are readily available, easily biodegradable, exhibit various modes of action, are less expensive and have low toxicity to humans and non-target organisms. Neem, pyrethrum, cotton and tobacco are known sources of botanical pesticides and have already been commercialized. Other sources of botanical pesticides include garlic, euphorbia, citrus, pepper among others. Species of Trichoderma, Bacillus, Pseudomonas, Beauveria have been commercialized as microbial pesticides. Biopesticides are however faced with challenges of formulation, registration, commercialization, acceptance and adoption. This paper describes several aspects of biopesticide development, including but not limited to, their sources, production, formulation, commercialization, efficacy and role in sustainable agriculture.展开更多
Macadamia is cultivated for its nutritious edible kernel. In Kenya, the crop is predominantly grown by smallholder farmers mainly for export markets. Macadamia trees also enhance agro-forestry conservation, in the Eas...Macadamia is cultivated for its nutritious edible kernel. In Kenya, the crop is predominantly grown by smallholder farmers mainly for export markets. Macadamia trees also enhance agro-forestry conservation, in the East African farmlands, by providing habitat and floral resources to beneficial arthropods such as insect pollinators. Allogamy of macadamia flowers is largely dependent on insects that pollinate and consequently influence the nut set, retention and yield. However, there is limited information on macadamia insect flower visitors in Kenya. This article assessed the diversity of insects that forage flowers of macadamia crop, and further evaluated their temporal distribution, in Murang’a county, central Kenya. Insect flower visitors were sampled weekly using a butterfly net for twelve consecutive months, from January 2021 to December 2021. Sixty-one insect species were recorded foraging macadamia flowers in Murang’a county, central Kenya. There was a statistical difference in the Simpson diversity index among weather seasons, dry, long rain, cold and short rain (p Apis mellifera), a key pollinator species, being the most abundant flower visitor. This study provides strong baseline information, to scientists and farmers, on probable macadamia pollinator species, in central Kenya. .展开更多
Shelling of groundnut pods using manual decorticators in Kenya is characterized by high kernel breakages and low shelling efficiencies. As a result, farmers get low income due to low cost of broken kernels and a lot o...Shelling of groundnut pods using manual decorticators in Kenya is characterized by high kernel breakages and low shelling efficiencies. As a result, farmers get low income due to low cost of broken kernels and a lot of time is lost in the tedious shelling operation. To overcome this problem, pertinent parameters that influence shelling efficiency of manually operated groundnut decorticators were identified. Two manually operated decorticators were tested and modifications done on one of the decorticators to optimize its technical performance. Results of machine performance tests showed that for WBS (Wooden beater sheller) at a feed rate of 30 kg/hr and 22.6 mm clearance, shelling efficiency increased with decrease in moisture content for all the groundnut varieties. The highest shelling efficiency was 55.3% for ICGV 99568, 39.2% for ICRISAT Groundnut Variety (ICGV) 90704 and 29% for ICGV 12991 at moisture content of 5.92% wb. For RBS (Rod beater sheller) at a feed rate of 30 kg/hr and 22.6 mm clearance, the highest shelling efficiency was 58.3% for ICGV 99568, 42.7% for ICGV 90704 and 35% for ICGV 12991 at moisture content of 7% wb. Identification of the pertinent parameters showed that pod moisture content, clearance and sieve size influence performance of manually operated groundnut. Theoretical predictive models developed were optimized which showed that a maximum shelling efficiency of 88.73% can be achieved with percent damage of 4% when the sieve size is 11 mm and clearance is 16 mm with a regression coefficient of over 85%. With the modifications done on the WBS decorticator, the highest shelling efficiency of 87% was obtained at a clearance of 10 mm for ICGV 99568 which is the largest in size from the three varieties. The shelling efficiency of the modified decorticator is far above those of the RBS and WBS because the sieve sizes and clearances of the later were not optimized. The results of the theoretical optimization of the manually operated groundnut decorticator implies that farmers who shell for seeds can now obtain more seeds shelled with low breakage and therefore will get more income.展开更多
Solid waste dumping is a hectic problem in urban and developing areas due to shortage of land for the purpose. The main objective of this study was to select potential areas for suitable solid waste dumping for Kajiad...Solid waste dumping is a hectic problem in urban and developing areas due to shortage of land for the purpose. The main objective of this study was to select potential areas for suitable solid waste dumping for Kajiado County, Kenya. Eight input map layers including DEM （digital elevation model）, topography, urban settlement, roads, wetlands, rivers, forests and protected areas were prepared and MCDA （Multi Criteria Decision Analysis Methods） were implemented in a GIS （geographic information systems） environment. GIS, RS （remote sensing） and MDCA are powerful tools which can effectively be applied during the planning phase of solid waste management in order to avoid adverse catastrophes in future. The final suitability map was prepared by weighted overlay analyses and leveled as the most suitable, moderate suitable, less suitable and unsuitable areas. The area of each suitability level was calculated using spatial statistics. Polygons representing the most suitable sites were further analyzed in terms of area perimeter ratio in order to investigate the most suitable areas in terms of shape regularity. The leading four polygons considered were marked A, B, C, D respectively in the final map. This study showed that suitable areas for solid waste landfills were limited and scattered in the study area.展开更多
In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass str...In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass strip on biomass yield and light use efficiency. Maize/cowpea intercropped with senna siamea or grass stripped were compared with sole maize and cowpea. A ceptometer was applied to measure PAR interception by sole maize or cowpea or crop/tree and grass/crop interfaces and separation of PAR used by each plant or tree/grass component. Hedgerow intercropping increased PAR interception and biomass formation. C4 plants had higher LUE than C3 plants while combining C4 and C3 in the agroforestry system lowered LUE. The tree/crop interfaces increased PAR interception than at 1 m and 2 m away from the hedgerow. The row of maize or cowpea at lm intercepted more PAR than the row at 2 m from hedgerow while the cowpea row next to the hedgerow was depressed compared to the rows in the middle rows which had higher yields. The maize or cowpea row next to the grass strip was more stressed than the rows in the middle of the alley.展开更多
The objective of this work was to evaluate genotypes of wheat depending on doses of N in order to determine the best value of N and the components of productivity of wheat. Experiment was carried out in Pato Branco—P...The objective of this work was to evaluate genotypes of wheat depending on doses of N in order to determine the best value of N and the components of productivity of wheat. Experiment was carried out in Pato Branco—PR in soil classified as Eutrophic typical RED LATOSOL. The experimental design was randomized blocks, in 3 × 5 (× N doses genotypes), with three repetitions. The genotypes were: CD 108, CD 115 and BRS 220, and the doses of n were: zero;20;40;80 and 120 kg of N·ha-1, applied at the beginning of tillering. After harvest assessed number of Spike (NE), Tang (EC) length, grains per Spike (GE), mass of thousand grains (MMG), grain yield (R) and weight/HL (PH), application of N increased the NE and R, and however decreased to MMG. The genotypes differed among themselves, featuring better performance of the NE (the BRS 220), CE (the CD 115) and R (the CD 108). There were positive correlations between the doses of N with the NE and R and be-tween NE with the R, and negative correlation between doses of N with the MMG. It is concluded that the NE is the main factor that affects the R with N supply.展开更多
Kiwifruit bacterial canker,caused by Pseudomonas syringae pv.actinidiae(Psa),is a significant threat to the kiwifruit industry.The two-component signaling systems(TCSs) play a crucial role in regulating the virulence ...Kiwifruit bacterial canker,caused by Pseudomonas syringae pv.actinidiae(Psa),is a significant threat to the kiwifruit industry.The two-component signaling systems(TCSs) play a crucial role in regulating the virulence of P.syringae,yet their specific function in Psa remains largely unclear.In this study,we found that disrupting the TCS RegAB(encoded by Psa 802/Psa_ 803) resulted in a notable increase in the virulence of P.syringae pv.actinidiae M228(Psa M228) in host plant and hypersensitive reaction(HR) in nonhost plant.Through comparative transcriptome analysis of the Psa M228wild-type strain and the regA mutant,we identified the pivotal role of RegAB in controlling various physiological pathways,including the type Ⅲ secretion system(T3SS),a key determinant of Psa virulence.Additionally,we discovered that the RegA has binding sites in the promoter region of the hrpR/S,and the transcriptional level of the hrpR and other T3SSrelated genes increased in the regA deletion strain relative to the Psa M228 wild-type.The DNA-binding affinity of RegA,and therefore the repressor function,is enhanced by its phosphorylation.Our findings unveil the function of TCS RegAB and the regulatory mechanism of T3SS by RegAB in Psa,highlighting the diverse functions of the RegAB system.展开更多
文摘Use of synthetic pesticides to manage crop pests has had a toll on human health, environmental safety and farmer’s income creating a need for alternative crop protection strategies. Botanical pesticides have been reported to be effective in managing crop pests, and a number of them have been formulated and commercialized. This study was conducted in North-Eastern Tanzania to establish the pesticidal and medicinal value of turmeric (Curcuma longa) and ginger (Zingiber officinale). Purposive sampling was adopted to select and interview 167 respondents drawn from farmers, traders, pharmaceutical shops, agro-shop operators and consumers of turmeric and ginger. Ginger and turmeric rhizomes were also collected for extraction, antifungal assay and biochemical analysis. Results showed that majority of the respondents were aware of the medicinal value of ginger and turmeric, with 59.5% having used the plants to treat respiratory related infections and healing skin surface and internal wounds. About 14% of farmers were aware of and had used aqueous botanical preparations from neem, moringa and Tephrosia to manage insect pests. Only 2.7% of farmers had used ginger powder as a protective insecticide on stored grains. Ginger and turmeric rhizome extracts showed high antifungal activity against Pythium (83% - 95%), Fusarium oxysporum f. sp. lycopersici (34% - 52%) and Alternaria solani (38% - 53%). A GC-MS analysis of ginger and turmeric extracts showed presence of α-zingiberene, β-sesquiphellandrene, α-farnesene, ar-curcumene, α-copaene, ar-tumerone and curlone. This study recommends that ginger and turmeric extracts be considered for development of a botanical pesticide and especially for management of damping off diseases.
文摘A substantial body of research has been conducted with the objective of enhancing the understanding of Non-Timber Forest Products (NTFP) in Central Africa. A significant proportion of the studies focus on medicinal plants, in contrast to those that examine food products. Nevertheless, studies on edible wild mushrooms as NTFPs and cultivated mushrooms, on their economic potential and value chains in the Great Lakes Region, remain scarce and largely absent for some NTFPs. In light of the aforementioned considerations, the present study aims to examine the economic potential and value chain of the production sector of wild edible mushrooms (WEM) and cultivated mushrooms (CM) within the Virunga National Park (PNVi) and its surrounding areas in North Kivu, Democratic Republic of the Congo (DRC). To this end, a sample of 432 respondents was selected, distributed equitably among the actors of the Goma-Kitshanga-Mweso value chain, the Goma-Rutshuru chain, the Beni-Mutwanga chain, and the Beni-Mangina chain. A digital questionnaire consisting of open and closed questions was administered, and observations were carried out concurrently. The quantities of mushrooms sold were weighed and photographed. The results demonstrated that, when the eight-month fruiting period of wild and cultivated mushrooms was considered as a single year for all actors within the value chain, a picker could sell 6.1 kg at $2 and earn $12. A seller could sell 16 kg at $4 and earn $64, while a grower could sell 502 kg at $3 and earn $1506. Consequently, the CM grower generates a significantly higher profit than other participants in the value chain, despite the expenses he incurs. Ultimately, the domestication of WEM, highly prized by the local population of the Virunga National Park, has the potential to enhance their household incomes, as evidenced by the findings of this study.
文摘The parasitic weed Striga poses a serious threat to cereal production in sub-Saharan Africa. For many years, technological packages for the control of this weed were proposed and implemented on farmers＇ fields. A survey was carried out in farmers＇ fields in 2010/201l cropping season in selected dryland areas of Tanzania to： （a） determine the Striga plant counts, number of capsules/Striga plant and agronomic practices used by farmers to control Striga; and （b） evaluate the relationship between Striga reproduction, soil chemical characteristics and agronomic practices. Soil samples at 0-20 cm depth were collected from 20 different farmers＇ fields. The soil samples were analyzed for pH, organic carbon, N, P and K. Results showed that there was low adoption of recommended Striga control methods. Regression analysis of agronomic practices and soil chemical characteristics revealed a positive improvement of soil N and organic carbon and reduction of soil P and K content as one shifted from sole planting to intercropping. The results showed that potassium was highly positively related to number of capsules/Striga plant. There was a reduction in the number of capsules/plant as one moved from sole planting to intercropping. Based on these findings, K in the Striga infested in soils positively influenced Striga reproduction and seed bank replenishment, hence high soil K levels may lead to high Striga incidence.
文摘The stability of soybean genotypes is very important in breeding programs for not only the evaluation, selection, and production of cultivars but also the establishment of parameters required for the classification of genotypes into relative maturity groups (RMG). The aim of this study was to define stable genotypes for traits, such as days to flowering, days to maturity, and length of the reproductive period, and to classify them into RMG. For this purpose, 20 commercial soybean cultivars were evaluated in 12 environments distributed in the major producing regions of Brazil. Assessments according to the Eberhart and Russell method and the additive main effects and multiplicative interaction (AMMI) method were effective in the identification of stable genotypes and their classification into RMG. These methods can also be used collectively for this purpose. Our results showed that the AMMI method led to a better interpretation of genotype-environment interactions. Thus, RMG obtained on the basis of stable genotypes represented a good estimate of the relative maturity of soybean crops throughout Brazil. *Corresponding author.
文摘Laboratory and green house experiments were carried out to evaluate the efficacy of fungicides, biological agents and host resistance in managing FHB and the associated T-2 toxin. In vitro activity of fungicides and antagonists was determined by paired culture method. Effect of microbial agents on FHB severity and mycotoxin content was determined by co-inoculating F. graminearum and F. poae with Alternaria spp., Epicoccum spp. and Trichoderma spp. Fungicides Pearl? (500 g/L carbendazim), Cotaf? (50 g/L hexaconacole), Thiovit? (micronised sulphur 80% w/w) and Folicur? (430 g/L tebuconazole) were the standard checks. Host resistance was determined by inoculating F. poae and F. graminearum to four wheat cultivars and fifteen lines in pot ex-periments. Fungicides resulted in 100% inhibition of pathogen radial growth in in vitro while microbial agents suppressed pathogen growth by up to 53%. Thiovit? and Trichoderma were the most effective in reducing FHB severity in green house pot experiments. The wheat cultivars and lines varied in susceptibility with cultivar Njoro BW II showing least susceptibility while line R1104, cv. Mbuni and cv. KIBIS were most susceptible. All the wheat cultivars and lines accumulated T-2 toxin by up to 5 to 28 μg/kg. The results indicated that neither fungicides nor antagonists can solely be relied on in managing FHB and toxin accumulation. Therefore, integration of biocontrol agents, fungicides and further breeding efforts to improve lines and cultivars with promising resistance to FHB and T2-toxin contamina-tion is recommended.
文摘In Uganda, grain amaranth is relatively new and has generally not been considered as an important crop compared to other grain crops and legumes. This study was therefore conducted to determine factors affecting adoption of grain amaranth growing, factors affecting production, and economic returns on investment of its production. The study was carried out in Kamuli district where a total of 174 grain amaranth farmers and 90 non-grain amaranth farmers were randomly selected and interviewed. Using descriptive statistics, regression analysis （logit model and a Cobb-Douglas type production function） and profitability ratios, it was found that grain amaranth is produced on a small scale and yields are low. Farmer adoption of the crop was favoured by age, gender （female）, education of the farmer, and source of income. The output was positively affected by the amount of labour and manure used in production, while a negative relationship existed between output and male farmers. The crop was most viable under small acreages （0.02-0.04 ha） with positive returns to investment of 0.016. Its production should therefore be encouraged because of its income generation potential and since it requires small land.
文摘Survey covering 120 wheat fields was conducted in three wheat-growing districts of Kenya during the 2008 cropping season to determine the incidence of Fusarium head blight (FHB) and T2-toxin contamination in grain. FHB incidence was determined as the number of blighted ears per 10m2. Information gathered included wheat production practices, rainfall and temperature data. Fungal pathogens were isolated from wheat stems, heads, straw, grains and soil and identified based on cultural and morphological characteristics. Wheat grain samples were analyzed for T2-toxin by competitive Enzyme Linked Immunosorbent Assay (ELISA). High FHB incidences of up to 88% were recorded. Fungal genera isolated included Fusarium, Epicoccum, Trichoderma, Alternaria and Penicilium. Wheat plant parts with high infection with Alternaria and Epicoccum had corresponding low levels of Fusarium spp. Whereas Fusarium spp. were the most common fungal pathogens in stems, heads and soil, Epicoccum was frequently isolated from straw and grains. Fusarium speciesisolated included F. poae, F. graminearum, F. stilboides, F. verticilloides, F. fusarioides, F. tricinctum and F. heterosporum with F. poae and F. graminearum accounting for approximately 40% of all Fusarium infections. T-2 toxin was detected in all the grain samples and varied from 3 to 22 ppb. The study showed that FHB and T2-toxin are prevalent in the study districts and the high diversity of Fusarium species implies a challenge in FHB management as well as a risk of chronic T2-toxin exposure to humans and livestock.
文摘The production of maize is constrained by parasitic weeds, particularly Striga. A study was carried out to document farmers＇ knowledge, attitude and practices on Striga control among smallholder farmers across three districts： Kisumu West, Busia and Teso South of Western Kenya. A multistage sampling technique was used to select the locations and farmers to be interviewed. A semi structured, open and closed ended questionnaire was administered leading to field experiment. Besides village meetings （39.2%）, farmers got informed on farming methods under Striga weed farms and its control technologies through neighbours （2.5%）, workshops and trainings （5.0%）, field schools （3.7%）, media （7.5%） and extension agents （10.8%）. The attitudes of farmers towards Striga control varied but frequently cited： long term viability of the Striga seed （12.5%）, difficult to control sharing of farm tools （10.8%）, expensive technologies （13.3%）, lack of adequate information （18.3%）, labour intensive （15.0%）, large farms for use of push and pull technology （1.7%） and time consuming （12.5%）. Framers used various Striga control practices but traditional methods （25%） were among the most used （25%）. Concerted effort involving researchers, extension agents and private sector are, therefore, required for wide scale dissemination and adoption of the existing modem control technologies.
文摘Currently the soybean crop is affected by the white mold (Sclerotinia sclerotiorum). The disease can reduce the crop yield and quality and decrease the prices of agricultural lands. The aim of the current research was to assess epidemiology of white mold on soybean crop grown at Arapoti, PR, Brazil, utilizing data related to agricultural practices and local meteorological factors. The experiment was conducted in a naturally infested area. The soybean crop was sown on October 18th, 2011. The experimental design adopted herein was a randomized block in a factorial combination with 4 row spacings (0.35, 0.45, 0.60, 0.75 m) and 4 plant populations (150, 200, 250, 300 thousand plants per hectare) and 4 replications. The temporal analysis of the epidemic was evaluated using mathematical models, such as Logistics, Monomolecular and Gompertz, in order to determine the best model that described the progress of the disease as a function of local meteorological elements. For the incidence data it has been shown that both logistic and monomolecular models were those that were best fitted to the experimental data. For severity, the best model related to the experimental data was the logistic one. Either for incidence or for severity, air temperature was considered to be the environmental factor most affecting the progress of the disease. The variability in the apparent infection rates of white mold on soybean was not affected by different row spacings and plant populations;therefore, suggesting that macroclimatic variations prevailed in such a fashion to mitigate the effect of cultural practices adopted in the field.
文摘Biopesticides are derivatives of plants, microorganisms and insects. Substances from plants and animals have been used to manage diseases in crops, animals and humans. Reliance on nature to heal nature is a practise for many people around the world. Use of natural products was overtaken by synthetic chemicals due to their efficacy, reliability and quick knock down effect. However, synthetic pesticides have become a health hazards for humans and environment due to their toxicity and pollution. Biopesticides are potential alternatives to synthetic pesticides. Sources of biopesticides are readily available, easily biodegradable, exhibit various modes of action, are less expensive and have low toxicity to humans and non-target organisms. Neem, pyrethrum, cotton and tobacco are known sources of botanical pesticides and have already been commercialized. Other sources of botanical pesticides include garlic, euphorbia, citrus, pepper among others. Species of Trichoderma, Bacillus, Pseudomonas, Beauveria have been commercialized as microbial pesticides. Biopesticides are however faced with challenges of formulation, registration, commercialization, acceptance and adoption. This paper describes several aspects of biopesticide development, including but not limited to, their sources, production, formulation, commercialization, efficacy and role in sustainable agriculture.
文摘Macadamia is cultivated for its nutritious edible kernel. In Kenya, the crop is predominantly grown by smallholder farmers mainly for export markets. Macadamia trees also enhance agro-forestry conservation, in the East African farmlands, by providing habitat and floral resources to beneficial arthropods such as insect pollinators. Allogamy of macadamia flowers is largely dependent on insects that pollinate and consequently influence the nut set, retention and yield. However, there is limited information on macadamia insect flower visitors in Kenya. This article assessed the diversity of insects that forage flowers of macadamia crop, and further evaluated their temporal distribution, in Murang’a county, central Kenya. Insect flower visitors were sampled weekly using a butterfly net for twelve consecutive months, from January 2021 to December 2021. Sixty-one insect species were recorded foraging macadamia flowers in Murang’a county, central Kenya. There was a statistical difference in the Simpson diversity index among weather seasons, dry, long rain, cold and short rain (p Apis mellifera), a key pollinator species, being the most abundant flower visitor. This study provides strong baseline information, to scientists and farmers, on probable macadamia pollinator species, in central Kenya. .
文摘Shelling of groundnut pods using manual decorticators in Kenya is characterized by high kernel breakages and low shelling efficiencies. As a result, farmers get low income due to low cost of broken kernels and a lot of time is lost in the tedious shelling operation. To overcome this problem, pertinent parameters that influence shelling efficiency of manually operated groundnut decorticators were identified. Two manually operated decorticators were tested and modifications done on one of the decorticators to optimize its technical performance. Results of machine performance tests showed that for WBS (Wooden beater sheller) at a feed rate of 30 kg/hr and 22.6 mm clearance, shelling efficiency increased with decrease in moisture content for all the groundnut varieties. The highest shelling efficiency was 55.3% for ICGV 99568, 39.2% for ICRISAT Groundnut Variety (ICGV) 90704 and 29% for ICGV 12991 at moisture content of 5.92% wb. For RBS (Rod beater sheller) at a feed rate of 30 kg/hr and 22.6 mm clearance, the highest shelling efficiency was 58.3% for ICGV 99568, 42.7% for ICGV 90704 and 35% for ICGV 12991 at moisture content of 7% wb. Identification of the pertinent parameters showed that pod moisture content, clearance and sieve size influence performance of manually operated groundnut. Theoretical predictive models developed were optimized which showed that a maximum shelling efficiency of 88.73% can be achieved with percent damage of 4% when the sieve size is 11 mm and clearance is 16 mm with a regression coefficient of over 85%. With the modifications done on the WBS decorticator, the highest shelling efficiency of 87% was obtained at a clearance of 10 mm for ICGV 99568 which is the largest in size from the three varieties. The shelling efficiency of the modified decorticator is far above those of the RBS and WBS because the sieve sizes and clearances of the later were not optimized. The results of the theoretical optimization of the manually operated groundnut decorticator implies that farmers who shell for seeds can now obtain more seeds shelled with low breakage and therefore will get more income.
文摘Solid waste dumping is a hectic problem in urban and developing areas due to shortage of land for the purpose. The main objective of this study was to select potential areas for suitable solid waste dumping for Kajiado County, Kenya. Eight input map layers including DEM （digital elevation model）, topography, urban settlement, roads, wetlands, rivers, forests and protected areas were prepared and MCDA （Multi Criteria Decision Analysis Methods） were implemented in a GIS （geographic information systems） environment. GIS, RS （remote sensing） and MDCA are powerful tools which can effectively be applied during the planning phase of solid waste management in order to avoid adverse catastrophes in future. The final suitability map was prepared by weighted overlay analyses and leveled as the most suitable, moderate suitable, less suitable and unsuitable areas. The area of each suitability level was calculated using spatial statistics. Polygons representing the most suitable sites were further analyzed in terms of area perimeter ratio in order to investigate the most suitable areas in terms of shape regularity. The leading four polygons considered were marked A, B, C, D respectively in the final map. This study showed that suitable areas for solid waste landfills were limited and scattered in the study area.
文摘In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass strip on biomass yield and light use efficiency. Maize/cowpea intercropped with senna siamea or grass stripped were compared with sole maize and cowpea. A ceptometer was applied to measure PAR interception by sole maize or cowpea or crop/tree and grass/crop interfaces and separation of PAR used by each plant or tree/grass component. Hedgerow intercropping increased PAR interception and biomass formation. C4 plants had higher LUE than C3 plants while combining C4 and C3 in the agroforestry system lowered LUE. The tree/crop interfaces increased PAR interception than at 1 m and 2 m away from the hedgerow. The row of maize or cowpea at lm intercepted more PAR than the row at 2 m from hedgerow while the cowpea row next to the hedgerow was depressed compared to the rows in the middle rows which had higher yields. The maize or cowpea row next to the grass strip was more stressed than the rows in the middle of the alley.
文摘The objective of this work was to evaluate genotypes of wheat depending on doses of N in order to determine the best value of N and the components of productivity of wheat. Experiment was carried out in Pato Branco—PR in soil classified as Eutrophic typical RED LATOSOL. The experimental design was randomized blocks, in 3 × 5 (× N doses genotypes), with three repetitions. The genotypes were: CD 108, CD 115 and BRS 220, and the doses of n were: zero;20;40;80 and 120 kg of N·ha-1, applied at the beginning of tillering. After harvest assessed number of Spike (NE), Tang (EC) length, grains per Spike (GE), mass of thousand grains (MMG), grain yield (R) and weight/HL (PH), application of N increased the NE and R, and however decreased to MMG. The genotypes differed among themselves, featuring better performance of the NE (the BRS 220), CE (the CD 115) and R (the CD 108). There were positive correlations between the doses of N with the NE and R and be-tween NE with the R, and negative correlation between doses of N with the MMG. It is concluded that the NE is the main factor that affects the R with N supply.
基金supported by the National Key Research and Development Program of China (2022YFD1400200 to Wang Yao and Yang Mingming)the National Natural Science Foundation of China (32330004 to Shen Xihui, 32170130 to Wang Yao and 32102283 to Yang Mingming)。
文摘Kiwifruit bacterial canker,caused by Pseudomonas syringae pv.actinidiae(Psa),is a significant threat to the kiwifruit industry.The two-component signaling systems(TCSs) play a crucial role in regulating the virulence of P.syringae,yet their specific function in Psa remains largely unclear.In this study,we found that disrupting the TCS RegAB(encoded by Psa 802/Psa_ 803) resulted in a notable increase in the virulence of P.syringae pv.actinidiae M228(Psa M228) in host plant and hypersensitive reaction(HR) in nonhost plant.Through comparative transcriptome analysis of the Psa M228wild-type strain and the regA mutant,we identified the pivotal role of RegAB in controlling various physiological pathways,including the type Ⅲ secretion system(T3SS),a key determinant of Psa virulence.Additionally,we discovered that the RegA has binding sites in the promoter region of the hrpR/S,and the transcriptional level of the hrpR and other T3SSrelated genes increased in the regA deletion strain relative to the Psa M228 wild-type.The DNA-binding affinity of RegA,and therefore the repressor function,is enhanced by its phosphorylation.Our findings unveil the function of TCS RegAB and the regulatory mechanism of T3SS by RegAB in Psa,highlighting the diverse functions of the RegAB system.
