Showing papers by "World Vegetable Center published in 2017"
TL;DR: To fully tap the economic and nutritional power of vegetables, governments and donors will need to give vegetables much greater priority than they currently receive.
150 citations
TL;DR: Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field and unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress.
Abstract: Ambient temperatures are predicted to rise in the future owing to several reasons associated with global climate changes. These temperature increases can result in heat stress- a severe threat to crop production in most countries. Legumes are well-known for their impact on agricultural sustainability as well as their nutritional and health benefits. Heat stress imposes challenges for legume crops and has deleterious effects on the morphology, physiology, and reproductive growth of plants. High-temperature stress at the time of the reproductive stage is becoming a severe limitation for production of grain legumes as their cultivation expands to warmer environments and temperature variability increases due to climate change. The reproductive period is vital in the life cycle of all plants and is susceptible to high-temperature stress as various metabolic processes are adversely impacted during this phase, which reduces crop yield. Food legumes exposed to high-temperature stress during reproduction show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to smaller seeds and poor yields. Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field. Omics approaches unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress.
144 citations
TL;DR: Results suggest that there is a need to support community-based programs to provide information on food and the importance of vegetables, their preparation, consumption and utilization to address food and nutrition challenges.
Abstract: Good nutrition is a prerequisite for a healthy and active life, especially for agriculture-dependent households. However, diets in most households in Tanzania lack diversity because the intake of meat, poultry, fish, and vegetables and fruits is low. This study estimates factors influencing dietary diversity of the household, children under five years, and women using primary survey data. It qualitatively assesses male dietary patterns and men's potential role in improving the nutritional status of the entire household. The findings show that the most consumed foods within the household are cereals, vegetables, oils and fats, spices, condiments and beverages. Children (d = 0.4; p<0.05) and women (d = 0.5; p<0.01) in female-headed households have low dietary diversity compared to those in male-headed households. Women and children access less diverse diets since 46% and 26%, achieved minimum dietary diversity respectively. Production of vegetables (coef. 0.34; p<0.05) play an important role in improving the dietary diversity of women. Gender (coef. 0.05; p<0.10) and education of the household head (coef. 0.02; p<0.01), food preparation and nutrition training (coef. 0.10; p<0.05) are important factors influencing dietary diversity of the members of a household. Results suggest that there is a need to support community-based programs to provide information on food and the importance of vegetables, their preparation, consumption and utilization to address food and nutrition challenges. Men can contribute towards improving household nutrition security by reducing consumption of food away from the home, especially during periods of food shortages. We recommend the use of complementary quantitative research to determine the patterns and dynamics of men's dietary diversity and compare it with that of other household members.
124 citations
TL;DR: Pesticide use was 42% less when a woman was in charge of pest management and 31% lessWhen farmers had adopted biopesticides, and relevant entry points for interventions aimed at reducing pesticide dependence are suggested.
107 citations
TL;DR: An analysis of the global occurrences and genebank holdings of cultivated eggplants and their wild relatives reveals that the WorldVeg genebank holds the world's largest public collection of the three cultivated eggplant species.
Abstract: Eggplant is the fifth most economically important solanaceous crop after potato, tomato, pepper and tobacco. Apart from the well-known brinjal eggplant (Solanum melongena L.), two other under-utilized eggplant species, the scarlet eggplant (S. aethiopicum L.) and the gboma eggplant (S. macrocarpon L.) are also cultivated. The taxonomy and identification of eggplant wild relatives is challenging for breeders due to the large number of related species, but recent phenotypic and genetic data and classification in primary, secondary and tertiary genepools, as well as information on the domestication process and wild progenitors, facilitates their utilization in breeding. The World Vegetable Center (WorldVeg) holds a large public germplasm collection of eggplant, which includes the three cultivated species and more than 30 eggplant wild relatives, with more than 3,200 accessions collected from 90 countries. Over the last 15 years, more than 10,000 seed samples from the Center’s eggplant collection have been shared with public and private sector entities, including other genebanks. An analysis of the global occurrences and genebank holdings of cultivated eggplants and their wild relatives reveals that the WorldVeg genebank holds the world’s largest public collection of the three cultivated eggplant species. The composition, seed dissemination and utilization of germplasm from the Center’s collection are highlighted. In recent years more than 1300 accessions of eggplant have been characterized for yield and fruit quality parameters. Further screening for biotic and abiotic stresses in eggplant wild relatives is a priority, as is the need to amass more comprehensive knowledge regarding wild relatives’ potential for use in breeding. However, as is the case for many other crops, wild relatives are highly under-represented in the global conservation system of eggplant genetic resources.
105 citations
TL;DR: It is concluded that further promotion of IPM adoption among farmers is needed and that it should be a priority to increase the profitability of IPM practices for gradual reduction in synthetic pesticide misuse and a sustainable agricultural production.
67 citations
TL;DR: Isoflavones, reported to have beneficial effects on human health, are found at high concentrations in soybean sprouts and could easily provide the recommended anticarcinogenic dose range from 1.5 to 2.0mg/kg of body weight per day.
57 citations
TL;DR: In this paper, the authors assessed the number of households and individuals lifted out of poverty and food insecurity in sub-Saharan Africa by adopting improved rice varieties over the period 2000-2014.
56 citations
TL;DR: Findings support the possible presence of broad-based insect and mite resistance in accessions closely related to cultivated tomato, and identify three new sources of T. urticae resistance.
Abstract: Tomato wild relatives are important sources of resistance to many pests of cultivated tomato [Solanum lycopersicum L. (syn. Lycopersicon esculentum Mill.)]. Eleven wild tomato accessions previously identified at AVRDC—The World Vegetable Center as resistant to Bemisia tabaci were evaluated for resistance to the two-spotted spider mite [Tetranychus urticae (Koch.)] based on egg numbers using the leaf disc and Tanglefoot no-choice bioassays, and damage scores in choice bioassays. Highest resistance based on choice and no-choice bioassays was identified in AVRDC S. galapagense accessions VI057400, VI045262, VI037869 and VI037239, and S. cheesmaniae accession VI037240, all of which are new sources of T. urticae resistance. In addition, S. pimpinellifolium accession VI030462 exhibited resistance only in the no-choice bioassay based on egg numbers. Resistance to T. urticae based on the number of eggs from the no-choice bioassays was positively correlated with density of type IV glandular trichomes and negatively correlated with densities of type V trichomes. All resistant accessions accumulated high levels of total acylsugars, which were positively associated with type IV trichomes. There was a significant negative relationship between acylsugar content and T. urticae egg numbers from the no-choice bioassays. There was high correlation between the results from the leaf disc test and the Tanglefoot no-choice bioassay. These findings support the possible presence of broad-based insect and mite resistance in accessions closely related to cultivated tomato.
53 citations
TL;DR: In this paper, the authors present an overview of the agronomic, economic, and environmental performances of low-tech protected cultivation techniques in sub-Saharan Africa as reported in the literature.
Abstract: Vegetable production in sub-Saharan Africa faces numerous agronomic constraints that will have to be overcome to feed the increasing population and to fight malnutrition. Technology transfer and the adoption of low-tech protected cultivation techniques affordable for smallholders are believed to be able to meet this challenge. Protected cultivation techniques are a set of agricultural practices aimed at artificializing the crop environment through the use of soil covers and/or plant covers to control pests and climatic conditions. Although protected cultivation techniques may increase the yield and quality of vegetable crops and extend their production periods worldwide, the transfer of these techniques in sub-Saharan Africa raises questions about their agronomical performances, their profitability but also their environmental impacts. Are low-tech protected cultivation techniques adapted to the sustainable production of vegetables by smallholders in sub-Saharan Africa? To answer this question, we present an overview of the agronomic, economic, and environmental performances of low-tech protected cultivation techniques in sub-Saharan Africa as reported in the literature. The major conclusions that can be drawn from the review are (1) low-tech protected cultivation techniques are not suitable in all climatic conditions in sub-Saharan Africa and need to be combined with other methods to ensure adequate pest control, (2) the profitability of protected cultivation techniques relies on the capacity to offset increased production costs by higher yields and higher selling prices to be obtained with off-season and/or higher quality products, (3) breaking with existing cropping systems, the lack of technical support and skills, and the limited access to investment funding are major obstacles to the adoption of protected cultivation techniques by smallholders (4) life cycle assessments conducted in northern countries suggested that more efficient use of agricultural inputs would offset the negative impacts of protected cultivation techniques if they are properly managed, but further studies are required to be sure these results can be extrapolated to sub-Saharan Africa context.
52 citations
TL;DR: In this article, the authors developed a new model based on Mathematical Programming-based Multi-Agent System (MPMAS), a simulation software that allows assessing exante the impact of alternative pesticide use reduction strategies, including combinations of pesticide taxes, the introduction of integrated pest management, a price premium for safe agricultural produce, and subsidies for biopesticides.
TL;DR: Whitefly resistance in S. cheesmaniae and S. pimpinellifolium accession VI037240 and VI030462 is noteworthy because these species are closely related to cultivated tomato and introgression of whitefly resistance should be relatively straightforward.
Abstract: The sweetpotato whitefly, Bemisia tabaci Genn., is a major pest of tomato (Solanum lycopersicum) and other crops throughout the tropics and subtropics. The objectives of this study were to characterize 255 accessions of S. galapagense, S. cheesmaniae and S. pimpinellifolium for trichome types, and to evaluate selected accessions with high densities of glandular trichomes for resistance to whitefly. Twenty-two accessions classified as either sparse or abundant for type IV trichomes were selected and evaluated for numbers of adults, eggs, nymphs, and puparium of whitefly in choice bioassays, for adult mortality and egg numbers in no-choice bioassays, and for densities of type I, IV, V, and VI trichomes. The highest whitefly resistance was detected in S. galapagense accessions VI063177 and VI037239 based on choice and no-choice bioassays. In addition, we found high levels of whitefly resistance in S. cheesmaniae accession VI037240 based on the choice bioassay and in S. pimpinellifolium accession VI030462 based on the no-choice bioassay. Whitefly resistance in VI037240 and VI030462 is noteworthy because these species are closely related to cultivated tomato and introgression of whitefly resistance should be relatively straightforward. High densities of type IV trichomes and low densities of type V trichomes were associated with reduced numbers of whitefly adults, nymphs, puparium, and eggs in the choice bioassay and with high adult whitefly mortality in the no-choice bioassay. Preliminary trichome analysis followed by choice and no-choice assays facilitated rapid identification of whitefly-resistant accessions from a large pool of candidates of different species.
TL;DR: In this article, the authors present qualitative and quantitative postharvest losses of tomato in Oromia National Regional State, Ethiopia, located southeast of Addis Ababa, and show that tomato production is being done by relatively young married individuals who have at least primary level education.
Abstract: Tomato has significant economic importance in Ethiopia. Although quantitative evidence is limited, postharvest loss in tomato is considerably high. This study presents qualitative and quantitative postharvest losses of tomato. The study was conducted in 2015 in two districts (Bora and Dugda) located in East Shewa Zone of Oromia National Regional State, Ethiopia, located southeast of Addis Ababa. Primary data were collected from producers (smallholder farmers) and traders via household survey, focus group discussions and key informant interviews as well as estimation of losses based on samples. Secondary data and information were collected from published and unpublished sources. Results indicate that tomato production is being done by relatively young married individuals who have at least primary level education. About three-quarter of land holding is allocated for vegetable production, which largely takes place under irrigation during dry season. All sample producers sold more than 95% of their tomato produce, mostly to wholesalers as compared to collectors and retailers. Postharvest losses occur at collectors, wholesalers and retailers level. The finding indicates that more than 16% of respondents encounter produce losses due to high incidence of diseases, insect pest and mechanical injuries, each of them accounting for more than 20% of postharvest losses. The findings from our study underscore that the ability of actors to mitigate postharvest losses is limited due to lack of technical know-how. They also lack necessary support and complementary resources to improve postharvest handling practices and technology.
TL;DR: Host plant resistance is a cost-effective and a safe alternative to control bruchids in mungbean and is associated with morphological, biochemical, and molecular traits that affect insect growth and development, thereby, reduce the yield losses by the pests.
Abstract: Mungbean (Vigna radiata (L.) R. Wilczek var. radiata) is an important pulse crop in Asia, and is consumed as dry seeds and as bean sprouts. It is an excellent source of digestible protein. Bruchids [Callosobruchus chinensis (L.) and Callosobruchus maculatus (F.)] are the important pests of mungbean and cause damage in the field and in storage. Bruchid infestation reduces the nutritional and market value of the grain and renders seeds unfit for human consumption, agricultural and commercial uses. These pests are controlled mainly by fumigation with highly toxic chemicals such as carbon disulphide, phosphene, and methyl bromide, or by dusting with several other insecticides, which leave residues on the grain, thus, threatening food safety. Some plant-based extracts have been found useful in controlling bruchids, but are not fully successful due to their short-term activity, rapid degradability, and potentially negative effect on seed germination. Although some wild sources of bruchid resistance in mungbean have been reported, which have been used to develop bruchid- resistant lines, undesirable genetic linkages threaten the proper exploitation of genetic diversity from wild germplasm into commercial cultivars. Further, biotype variation in bruchids has rendered some mungbean lines susceptible that otherwise would have been resistant to the pest. Host plant resistance is a cost-effective and a safe alternative to control bruchids in mungbean and is associated with morphological, biochemical and molecular traits. These traits affect insect growth and development, thereby, reduce the yield losses by the pests. Understanding the defense mechanisms against insect pests could be utilized in exploiting these traits in crop breeding. This review discusses different traits in mungbean involved in defense against bruchids and their utility in pest management. We also highlight the breeding constraints for developing bruchid-resistant mungbean and how can these constraints be minimized. We further highlight the importance of supporting conventional breeding techniques by molecular techniques such as molecular markers linked to bruchid resistance.
TL;DR: In this paper, the authors used climate and household survey data to analyse farmer perceptions regarding climate change, adaptation measures taken in response to these changes, and how well these perceptions correlate with meteorological data in Kenya.
Abstract: Climate change has had a significant impact on rain-fed agricultural production in developing countries. Smallholder farmers are the most vulnerable, and currently must make production decisions in a high risk and uncertain environment with regard to rainfall and temperature. This paper uses climate and household survey data to analyse farmer perceptions regarding climate change, adaptation measures taken in response to these changes, and how well these perceptions correlate with meteorological data in Kenya. We find that a significant number of farmers perceive climate change as real, and that they are particularly concerned about changes in rainfall and temperature. Changing crop varieties is predominantly used as an adaptation measure since extension messages often encourage adoption of drought-resistant varieties. Major factors influencing farmer perceptions include age of the farmer, which is often associated with more farming experience and subsequent extension service. Except in low potential zones, farmers' perceptions of climatic variability are in line with climatic data records. Better education, access to extension messages, farm size and credit facilities are necessary for farmers to decide to adapt to climate change. The paper further assesses barriers to the adoption of various adaptation strategies, and lack of finances and knowledge have been found to inhibit adaptation response within the smallholder farming sector. Findings imply that effective adaptation to threats posed by climate variability and change requires a multi-dimensional collaborative approach, with different stakeholders playing key roles in providing support services in terms of education, extension, credit and meteorological information.
TL;DR: In this paper, the authors used temporally and spatially disaggregated weather data and three waves of household panel survey data to understand the impact of weather extremes on household welfare.
Abstract: Households in rural Kenya are sensitive to weather shocks through their reliance on rain-fed agriculture and livestock. Yet the extent of vulnerability is poorly understood, particularly in reference to extreme weather. This paper uses temporally and spatially disaggregated weather data and three waves of household panel survey data to understand the impact of weather extremes –including periods of high and low rainfall, heat, and wind– on household welfare. Particular attention is paid to heterogeneous effects across agro-ecological regions. We find that all types of extreme weather affect household well-being, although effects sometimes differ for income and calorie estimates. Periods of drought are the most consistently negative weather shock across various regions. An examination of the channels through which weather affects welfare reveals that drought conditions reduce income from both on- and off-farm sources, though households compensate for diminished on-farm production with food purchases. The paper further explores the household and community characteristics that mitigate the adverse effects of drought. In particular, access to credit and a more diverse income base seem to render a household more resilient.
TL;DR: Progress made towards the adverse effects of abnormal temperatures on various growth stages in legumes is described and appropriate strategies to resolve these effects are proposed.
Abstract: Of the various environmental stresses that a plant can experience, temperature has the widest and most far-reaching effects on legumes. Temperature extremes, both high (heat stress) and low (cold stress), are injurious to plants at all stages of development, resulting in severe loss of productivity. In response to unfavorable temperatures, plant biomolecules such as stress proteins, enzymatic and non-enzymatic antioxidants, organic osmolytes and phytohormones come into play, usually, as a part of the plant defense mechanisms. The accumulation of these molecules, which may be useful as metabolic indicators of stress tolerance, depend on the plant species exposed to the temperature stress, its intensity and duration. Some of these molecules such as osmolytes, non-enzymatic antioxidants and phytohormones may be supplied exogenously to improve temperature stress tolerance. Legumes show varying degrees of sensitivity to high and low-temperature stresses, which reduces their potential performance at various developmental stages. To address the ever-fluctuating temperature extremes that various legumes are being constantly exposed, efforts are being made to develop tolerant plant varieties via conventional breeding methods as well as more recent molecular breeding techniques. In this review, we describe the progress made towards the adverse effects of abnormal temperatures on various growth stages in legumes and propose appropriate strategies to resolve these effects.
TL;DR: The identification of high level of tolerance in mungbean lines such as ML 1628 and of resistance in black gram and rice bean provides hope for tackling the disease through resistance breeding.
Abstract: Mungbean (Vigna radiata (L.) Wilczek) is an important pulse crop in India. A major constraint for improved productivity is the yield loss caused by mungbean yellow mosaic disease (MYMD). This disease is caused by several begomoviruses which are transmitted by the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). The objective of this study was to identify the predominant begomoviruses infecting mungbean and the major cryptic species of B. tabaci associated with this crop in India. The indigenous B. tabaci cryptic species Asia II 1 was found dominant in Northern India, whereas Asia II 8 was found predominant in Southern India. Repeated samplings over consecutive years indicate a stable situation with, Mungbean yellow mosaic virus strains genetically most similar to a strain from urdbean (MYMV-Urdbean) predominant in North India, strains most similar to MYMV-Vigna predominant in South India, and Mungbean yellow mosaic India virus (MYMIV) strains predominant in Eastern India. In field studies, mungbean line NM 94 showed a high level of tolerance to the disease in the Eastern state of Odisha where MYMIV was predominant and in the Southern state of Andhra Pradesh where MYMV-Vigna was predominant, but only a moderate level of tolerance in the Southern state of Tamil Nadu. However, in Northern parts of India where there was high inoculum pressure of MYMV-Urdbean during the Kharif season, NM 94 developed severe yellow mosaic symptoms. The identification of high level of tolerance in mungbean lines such as ML 1628 and of resistance in black gram and rice bean provides hope for tackling the disease through resistance breeding.
TL;DR: The extent of genetic diversity in this material to provide basic information for its use in breeding programs was assessed and no correlation between fresh leaf yield and other traits was detected, whereas the number of pods per plant and the hundred seed weight were negatively correlated.
TL;DR: After one year of intervention, there was a significant (p < 0.01) increase in children’s awareness about fruit and vegetables, but these improvements in intermediary outcomes did not translate into significant improvements in fruit and vegetable consumption or nutritional status.
Abstract: This study evaluates the combined impact of school gardens linked to complementary lessons and promotional activities about gardening and nutrition on the nutritional awareness, knowledge, perceptions, eating behaviour and nutritional status of 10- to 15-year-old schoolchildren in Nepal. We used a cluster randomised controlled trial design to collect data from 30 schools and a sample of 1275 and 785 schoolchildren for the 2014 and 2015 school years, respectively. After one year of intervention, we found a significant (p < 0.01) increase in children’s awareness about fruit and vegetables, their knowledge about sustainable agriculture, their knowledge about food, nutrition and health and their stated preferences for eating fruit and vegetables. However, these improvements in intermediary outcomes did not translate into significant improvements in fruit and vegetable consumption or nutritional status. To influence children’s food decisions, it may be required to work more intensively with parents and...
TL;DR: There was strong negative correlation between larval mortality and adults emerged percentages in the no-choice feeding bioassays and the resistance sources reported here will be valuable in breeding tomato varieties resistant to this insect and others.
Abstract: The tomato leaf miner (Tuta absoluta) is a serious pest of tomato (Solanum lycopersicum) in the tropics and subtropics. Previous World Vegetable Center studies identified selected accessions of S. galapagense, S. cheesmaniae and S. pimpinellifolium that were resistant to whitefly (Bemisia tabaci Genn.) and spider mite (Tetranychus urticae Koch). Here, we evaluated these accessions for resistance to T. absoluta based on the number of eggs from choice bioassays, and larval mortality and adults emerged percentages in no-choice feeding bioassays at WorldVeg Eastern and Southern Africa (WorldVeg) and the International Centre for Insect Physiology and Ecology (icipe). At WorldVeg, S. galapagense VI063177 exhibited high resistance in both choice and no-choice bioassays. There was strong negative correlation between larval mortality and adults emerged percentages in the no-choice feeding bioassays. Results from the icipe experiments were consistent with those of the WorldVeg screening, except for S. pimpinellifolium accession VI030462, which was susceptible at icipe. Tuta absoluta is rapidly spreading and the resistance sources reported here will be valuable in breeding tomato varieties resistant to this insect and others.
TL;DR: The genomic SSR markers developed in this study have considerable potential value in advancing bitter gourd research.
Abstract: Bitter gourd (Momordica charantia) is widely cultivated as a vegetable and medicinal herb in many Asian and African countries. After the sequencing of the cucumber (Cucumis sativus), watermelon (Citrullus lanatus), and melon (Cucumis melo) genomes, bitter gourd became the fourth cucurbit species whose whole genome was sequenced. However, a comprehensive analysis of simple sequence repeats (SSRs) in bitter gourd, including a comparison with the three aforementioned cucurbit species has not yet been published. Here, we identified a total of 188,091 and 167,160 SSR motifs in the genomes of the bitter gourd lines ‘Dali-11’ and ‘OHB3-1,’ respectively. Subsequently, the SSR content, motif lengths, and classified motif types were characterized for the bitter gourd genomes and compared among all the cucurbit genomes. Lastly, a large set of 138,727 unique in silico SSR primer pairs were designed for bitter gourd. Among these, 71 primers were selected, all of which successfully amplified SSRs from the two bitter gourd lines ‘Dali-11’ and ‘K44’. To further examine the utilization of unique SSR primers, 21 SSR markers were used to genotype a collection of 211 bitter gourd lines from all over the world. A model-based clustering method and phylogenetic analysis indicated a clear separation among the geographic groups. The genomic SSR markers developed in this study have considerable potential value in advancing bitter gourd research.
TL;DR: The combined effect of school gardens linked to complementary lessons and promotional activities on the eating behavior and nutritional status of 9- to 15-year-old schoolchildren in Bhutan significantly increased children’s awareness about vegetables, their knowledge about sustainable agriculture, and their preferences for healthier foods.
Abstract: School gardening interventions have been touted as an effective approach to improve children’s eating habits in developed countries, but there is little evidence for their impact in developing countries. We studied the combined effect of school gardens linked to complementary lessons and promotional activities on the eating behavior and nutritional status of 9- to 15-year-old schoolchildren in Bhutan. We also studied the effect on a range of secondary indicators derived from the impact pathway. We used data from 468 schoolchildren in 9 control and 9 treatment schools following a randomized controlled trial design. We found that the school gardening intervention significantly increased children’s awareness about vegetables, their knowledge about sustainable agriculture, and their preferences for healthier foods. We found an 11.7-percentage point increase in the probability that children included vegetables in their meals (p < 0.05), but not in the number of different fruits or vegetables consumed. These results support the idea that comprehensive school garden interventions, combining gardening with education and promotion, can positively influence food preferences and food behavior in developing countries.
TL;DR: This study revealed chromosome numbers of 2n = 34 in root tip metaphase cells from one entry of Cleome gynandra, an African leafy vegetable with a potential to improve food security and micronutrient deficiencies.
Abstract: Cleome gynandra (L.) Briq. is an African leafy vegetable with a potential to improve food security and micronutrient deficiencies. Cytological traits, breeding biology and genetic diversity of 30 selected entries of C. gynandra from six African countries were investigated. The entries consisted of advanced lines, gene bank accessions and farmers’ cultivars. Our study revealed chromosome numbers of 2n = 34 in root tip metaphase cells from one entry. The 30 entries were found to be diploid with genome sizes ranging from 2.31 to 2.45 pg/2C. Hand pollination experiments were carried out to assess self-incompatibility within the entries and revealed that they are self- and cross-compatible. For genetic diversity studies within and among the entries, the pooled data of 499 polymorphic bands from 11 amplified fragment length polymorphism primer combinations and nine simple sequence repeat markers were used. The genetic distance among the entries ranged from 0.13 to 0.77. In a principal coordinate analysis, the farmers’ cultivars formed a cluster separate from the advanced lines and the gene bank entries, and the latter were not well resolved.
TL;DR: Validation studies of both markers in F2 populations revealed that individually their ability to correctly predict resistant genotypes (selection efficiency) was 65%.
TL;DR: In this article, the adoption and impact of improved tomato and African eggplant varieties developed through international agricultural research, released by national agricultural research and extension systems, and supplied to farmers by private seed companies in East and Southern Africa from 1990 to 2014.
TL;DR: A preliminary evaluation of genetic diversity in bitter gourd flesh (without seeds) for phytonutrient contents with the aim to understand whichphytonutrients might be increased through breeding and assess the association between fruit traits and phytonUTrient contents.
Abstract: Bitter gourd (Momordica charantia L.) is an important market vegetable in the tropics. The objectives of this study were to (1) conduct a preliminary evaluation of genetic diversity in bitter gourd flesh (without seeds) for phytonutrient (carotenoid, ascorbic acid and tocopherol) contents with the aim to understand which phytonutrients might be increased through breeding, (2) assess the association between fruit traits and phytonutrient contents and (3) evaluate the effect of the fruit harvest stage on phytonutrient contents. A total of 17 diverse bitter gourd entries of various commercial market types were evaluated for fruit traits and phytonutrient contents for 2 years. Significant differences (P= 0.05) among the entries were detected for total carotenoids, total tocopherols, dry matter and fruit traits. Mean total carotenoid contents of the entries ranged from 10 to 1335 μg/100 g fresh weight in year 1 and 10 to 1185 μg/100 g fresh weight in year 2. Mean ascorbic acid contents were 69 and 61 mg/100 g fresh weight in year 1 and year 2, respectively. Total tocopherol contents among the entries ranged from 480 to 1345 and 445 to 2145 μg/100 g fresh weight in year 1 and year 2, respectively. Total carotenoid and ascorbic acid contents were highest at 12 days after fruit set (DAFS), but total tocopherol contents were highest from 14 to 20 DAFS. A 100 g portion of bitter gourd fruit can meet 190, 17 and 8% of the recommended daily allowances of vitamin C, vitamin E and vitamin A, respectively, for adults.
TL;DR: Bacterial wilt is widely distributed in Benin and was found in five of the eight agro-ecological zones (AEZ) of Benin, which correspond to eight of the 12 districts ofBenin.
TL;DR: Describing genetic diversity for 38 newly collected isolates and three historical isolates revealed that ploidy varies by linkage group, and it appears the A2 clonal lineages may have switched mating type due to increased ploidsy.
Abstract: Phytophthora capsici is a devastating disease of pepper (Capsicum sp.) in Taiwan causing complete loss of commercial fields. The objective of this study was to characterize genetic diversity for 38 newly collected isolates and three historical isolates. Analysis of data includes whole genome sequence for two new isolates and for two isolates collected previously in 1987 and 1995. In addition, 63 single nucleotide polymorphism loci were genotyped using targeted-sequencing, revealing 27 unique genotypes. Genotypes fell into three genetic groups: two of the groups contain 90% (n = 33) of the 2016 isolates, are triploid (or higher), are exclusively the A2 mating type and appear to be two distinct clonal lineages. The isolates from 2016 that grouped with the historical isolates are diploid and the A1 mating type. Whole genome sequence revealed that ploidy varies by linkage group, and it appears the A2 clonal lineages may have switched mating type due to increased ploidy. Most of the isolates were recently race-typed on a set of differential C. annuum, and although there was no direct correlation between virulence and ploidy, many of the triploid isolates were less virulent as compared to the historical diploid isolates. The implications for breeding resistant pepper and conducting population analyses are discussed.
13 Jan 2017
TL;DR: In this paper, an environmental impact assessment based on gardeners' inputs was conducted along the rural-urban continuum of Bamenda in the Northwest Region Cameroon, where a survey questionnaire was administered among 150 growers divided equally in rural and peri-urban areas.
Abstract: It is predicted that by the year 2050, majority of Africans will living in urban area. In Cameroon, urbanization rate radically evolved from 37.8 % in 1987 to 52.0 % in 2010 and projections for 2030 show that 2 out of 3 Cameroonians will live in urban areas. Such a situation will outstrip job creation and the capacity of Africans governments to control and provide essential infrastructure. It will also an increase of unemployment as well as underemployment, poverty, food insecurity and health risks among those living in and around cities. Urban and peri-urban agriculture appear to be a better response to these challenges, as observed in the case of Bamenda, where local productions around the town (rural urban continuum) remain essential to feeding citizens. However, environmental impacts studies have not been carried out to examine qualitative and quantitative positive impacts of these activities centered on crop production, mainly production of leafy traditional vegetables around the cities. The actual context of sustainable development requires a better understanding between the vegetable gardening and the environment, which was the main focus of research. An environmental impact assessment based on gardeners’ inputs was conducted along the rural-urban continuum of Bamenda in the Northwest Region Cameroon. A survey questionnaire was administered among 150 growers divided equally in rural and peri-urban areas. The survey strongly insisted on the determination of active composition, families and chemical classes using the Phytosanitary Index ACTA, as well as the list of Cameroon registered pesticides. Data on environmental impacts were processed and analyzed through the Leopold and Fecteau matrices. Two variables were used for this: original impacts factorial (crop management) and production systems. The main results show that the majority of gardeners were young (34.67 %) of 30 to 40 years age group. Most of the gardeners in urban areas (88%) grow vegetables in home gardens of smaller size (less than 0.05 ha) while in peri-urban area, 76 % of respondents have farms measuring between 0.1 to 0.25ha located near their homes. In rural areas, the majority of growers (48 %), operating away from their habitat, owned farms larger or equal to 0.25 ha. Among the chemical used in production systems on the continuum were Carbonates and Thiocarbonates (35 %) followed by organophosphate (21 %), unidentified Pyrethroids synthetic components (17 %) and Organochlorines (4 %). The threshold of environmental impacts criticality is established and appears greater or equal to the average value of 16 in the rating scale. The results of this survey confirmed that there was an uncontrolled use of chemical fertilizers on vegetables throughout the rural-urban continuum of Bamenda. The study identified lack of training and gardeners’ sensitization as well as the non-compliance to the legal texts relating to the safe use of chemical fertilizers and chemicals, as the aggravating factors and causes of environmental damage around rural-urban Bamenda. Resume Il est prevu que d’ici 2050, la majorite des Africains vivront en milieu urbain. Au Cameroun, le taux d’urbanisation a radicalement evolue, passant de 37,8% en 1987 a 52,0% en 2010 et les projections pour 2030 montrent que 2 Camerounais sur 3 vivront dans des zones urbaines. Une telle situation sera superieure a la creation d’emplois et a la capacite des gouvernements africains a controler et a fournir l’infrastructure essentielle. On assistera egalement a une augmentation du chomage ainsi que du sous-emploi, l’accentuation de la pauvrete, l’insecurite alimentaire et des risques de sante chez les personnes vivant dans les centres urbains et periurbains. L’agriculture urbaine et periurbaine semble etre une meilleure reponse a ces defis, comme on l’observe dans le cas de Bamenda, ou les productions locales autour de la ville (continuum urbain-rural) restent indispensables a l’alimentation des citoyens. Cependant, des etudes d’impacts environnementaux n’ont pas ete menees pour examiner les impacts qualitatifs et quantitatifs positifs de ces activites centrees sur la production agricole, principalement la production de legumes traditionnels autour des villes. Le contexte actuel du developpement durable exige une meilleure comprehension des relations entre les cultures maraicheres et de l’environnement, ce qui etait l’objectif principal de la recherche. Une evaluation de l’impact environnemental de ces cultures au milieu des producteurs a ete realisee le long du continuum rural-urbain de Bamenda dans la region du Nord-Ouest Cameroun. Un questionnaire a ete administre aupres de 150 producteurs repartis egalement dans les zones rurales et periurbaines. L’enquete a fortement insiste sur la determination de la masse active, les familles et les classes chimiques en utilisant le phytosanitaires Index ACTA, ainsi que la liste des pesticides homologues au Cameroun. Les donnees sur les impacts environnementaux ont ete traitees et analysees par la matrice de Leopold et la grille de Fecteau. Deux variables ont ete utilisees pour cela: impacts originaux factoriels (gestion des cultures) et les systemes de production. Les principaux resultats montrent que la majorite des producteurs etaient jeunes avec 34,67% situes dans la tranche de 30 a 40 ans. La plupart des agriculteurs dans les zones urbaines (88%) cultivent des legumes dans les jardins familiaux de plus petite taille (moins de 0,05 ha), tandis que dans la zone periurbaine, 76% des repondants ont des parcelles mesurant entre 0,1 a 0.25ha et situees a proximite de leur domicile. Dans les zones rurales, la majorite des producteurs (48%), travaillent loin de leur habitation dans des champs de superficie superieure ou egale a 0,25 ha. Parmi les produits chimiques utilises dans les systemes de production dans ce continuum on releve des carbonates et thiocarbonates (35%), suivis par les pesticides organophosphores (21%), les pyrethroides synthetiques a composants non identifies (17%) et les organochlores (4%). Le seuil des impacts environnementaux de criticite etablie est superieur ou egal a la valeur moyenne de 16 dans l’echelle de cotation. Les resultats de cette enquete ont confirme qu’il y avait une utilisation incontrolee des engrais chimiques sur les legumes tout au long du continuum rural-urbain de Bamenda. L’etude a identifie le manque de formation et de sensibilisation des maraichers ainsi que la non-conformite aux textes juridiques relatifs a la securite dans l’utilisation des engrais et des produits chimiques, comme des facteurs aggravants et les causes de degradation de l’environnement autour de Bamenda rurale-urbaine.