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Can cultivars from participatory plant breeding improve seed provision to small-scale farmers? Conny J. All traders in Dak Lak acquired their stakes from a single source in the survey year, except one who listed two sources, and all of the suppliers of stakes were farmers that the trader knew personally. In Tay Ninh all traders purchased from multiple sources, with one trader reporting eight different sources within the single season. All traders mixed stakes together when they acquired them from multiple sources. Traders from Tay Ninh reported selling to 15—20 farmers in the previous season, while those from Dak Lak served from 20 to farmers.
Six of the 12 traders from Tay Ninh indicated that they traded stakes into Cambodia themselves, or sold stakes at the Chang Riec border gate into Cambodia, while the remainder of their sales were within Tay Ninh province. By contrast, all stakes sold by the traders in Dak Lak originated in Tay Ninh province. Traders operating in Dak Lak all sold within their own province, with the exception of one who sold to two neighboring provinces, and another who sold to Cambodia. Our evaluation of the constituents and character of Cambodia and Vietnam's cassava seed systems in the present study was limited by our sample selection, which favored important cassava-producing regions of both countries, and our results should be interpreted in that light.
Similarly, due to the relative paucity of systematic research on the topic in Southeast Asia, many of the comparative studies contextualizing our findings are drawn from outside of the region. Our study provides a first situational analysis of the cassava seed systems in Cambodia and Vietnam. Cassava seed systems in both Cambodia and Vietnam were clearly predominantly farmer-led, with formal actors and marketing structures rarely mentioned. Prevalent use of self-supplied seed, pronounced reliance on social networks for exchange, and a near absence of agro-dealers in the supply chain are common in vegetatively propagated crops McGuire and Sperling, Government participation was rare in our study, and we found no involvement of the NGO or relief programs found in other developing country contexts e.
Private sector involvement was even rarer in Cambodia, with isolated mentions of participation of starch factories or market sellers. A similar lack of formal marketing structures was described in Amazonian cassava seed systems, where local exchange of planting materials through gifts among kin groups dominated seed exchange Elias et al.
Social relationships and norms influence the exchange of seed at local scales McGuire, ; Thomas and Caillon, , and implications for social prestige related to providing or receiving seed may modify exchange patterns. The most important exchange actors in our study were friends, neighbors, and relatives, however provision of seed to strangers approached a fifth of all seed provisions in Cambodia.
In addition, Table 5 demonstrates an imbalance between giving and receiving transactions. The role of seed in social standing may have similarly influenced our respondents. In addition, the sampling methods of this study selected nationally important cassava-growing areas in each country. Provisions of seed to others also involved recipients from outside the community. Cassava producers operating on the fringes of developed cassava production regions may exhibit different seed exchange patterns, such as less ready access to sources of seed, leading them to seek seed from more established production areas.
Further research is required to understand seed networks in areas where cassava is a less major crop. The inability of survey teams to reach all but a single trader listed by Cambodian farmers for follow-up interview is a reflection of the highly mobile and seasonal character of trading activities, similar difficulties to those documented in interviewing sweet potato vine traders in Uganda Rachkara et al. Only a third of Dak Lak's traders were farmers themselves, half viewed cassava seed trading as their main business, and all offered diversified services such as supplying credit and trading fresh roots.
Tay Ninh's stake traders, all themselves farmers based in the community, listed stake trading as their main business. These differences also have impacts on relationships and trust with clients. Traders operate in ever more precarious legal spaces Wattnem, , and their interactions with farmers take many forms, from systematic and recurrent to intermittent and opportunistic. The roles of cassava seed traders across different contexts remain poorly characterized, and the findings of the present study suggest their importance in connecting spatially disparate local seed networks, and the urgent need for further research elucidating trader activities and practices.
The motivations and environmental and social factors influencing decision-making at the household and commune scales merit further inquiry. Inter-province exchange was relatively uncommon in Vietnam, with transactions recorded between only a few sets of Southern neighboring provinces. Province—province exchanges were more frequent in Cambodia, especially involving the Northwest provinces of Banteay Meanchey, Oddar Meanchey, Pailin, and Battambang, Cambodia's major cassava production belt.
Our province—province exchange network thus likely underestimates actual exchange at larger scales typically requiring trader mediation. On a regional level, movements of large quantities of seed from Vietnam and Thailand into Cambodia are regular, involve volumes reaching millions of stakes per season, and mirror industrial root transport. Cambodia was a net sink of seed, recording no outgoing international trade. In addition to significant trans-border exchange, all trader respondents interviewed in Dak Lak reported obtaining their seeds from Tay Ninh, suggesting further inter-province trader movement in Vietnam not recorded in our farmer surveys due to the limitations of our sampling design.
Drivers of seed exchange at the inter-provincial and regional scales include cassava cropping area expansion, and the availability of inexpensive back freight shipping from cassava root and chip trading networks. These effectively subsidize long-distance transport in a mirror image of root flows to Vietnam and Thailand's processing centers. The department of agriculture and rural development DARD of Tay Ninh has identified 68 cassava processing factories in Tay Ninh province with a capacity of , tons per month, drawing on fresh root supply from a large surrounding area in both Vietnam and Cambodia DARD, DARD estimates 3.
Southeast Asia's climatic heterogeneity is an additional driver for regional stake exchange. In Indochina, processing factories frequently offer higher prices for off-peak root supply, incentivizing early harvest, and further extending stake storage times and hence losses. When chip markets are involved, sufficient time is needed for chopping roots often done manually and sun drying chips, similarly extending storage times. Ratanakiri, the lowest production intensity site in the study, was isolated from seed exchange with other provinces, with only a single resident trader.
Fine-scale factors such as proximity to major root product transport routes may greatly influence the frequency of chance interactions with transient traders. Vietnam's low-intensity site, Dak Lak, was the most farmer-dominated exchange system of the four case studies. However, interviews with local traders indicated frequent importation of seed from Tay Ninh province. Low-intensity sites also harbored the highest rates of accessing multiple seed sources, particularly reliance on self-saved seed and seed from acquaintances within the community Figure 2.
Provisions of seed to others, mostly farmers within the community, were also more common at these sites. Sales of seed were more important components of both acquisition and provision at high-intensity sites than their low-intensity counterparts. Seed provisions from high-intensity sites were primarily sales, while at low-intensity sites gifts were most important. Average volumes of stakes per provision at high-intensity sites were 2. High-intensity production sites had on average 1. When they did provide planting materials to others, farmers in high-intensity production sites were more likely to engage in high-volume sales, and a lower percentage of exchanges were within the commune compared to low-intensity sites Figure 2.
These trends suggest a commodification of seed supply in higher production intensity environments, where financial incentives drive high-volume, longer-distance transactions mediated by trader agents or larger landholders. Battambang, Cambodia's largest cassava producer in , recorded the highest volumes of seed movement in our study, with flows exceeding , stakes from both Thailand and Vietnam.
Trade with neighboring Cambodian provinces of Kampong Chhnang, Pailin, and a large volume of intra-provincial exchanges exceeding 1 million stakes were reported. The demands of Thai and Vietnamese processing markets have led many farmers to adopt early harvesting practices due to favorable off-peak prices, extending the operational season of starch processing facilities.
As a province, Tay Ninh appeared largely self-contained in terms of stake exchange. Trader supply and purchase of stakes exceeded that of any other external actor, unique among sites in our study Figure 2. Many farmers acquired new stakes annually from a trader in pre-arrangements in which the trader supplied quality seed, and farmers reciprocated harvest rights to their mature fields including both roots and stems.
By this arrangement, farmers avoided the labor and logistic complications of harvesting and storing large amounts of perishable planting materials. Trust-based relationships between farmers and seed traders are critical in both formal and informal seed networks Lyon, ; Bentley et al. Our survey found low varietal diversity, with a range of 1—4 varieties avg. Maintenance of varietal diversity may reflect differences in traditional knowledge, heritage, and management Pinton, , as demonstrated by Amazonian on-farm diversity ranging from 1 to 8 cultivars per household avg.
Cassava's role as a traditional staple in the Amazon contrasts starkly with its relatively recent introduction as a cash crop in Southeast Asia and accompanying distribution of industrial varieties originating from local breeding programs. Near exclusive focus on productivity may lead to decreased diversity in increasingly commercial production schemes Salick et al.
However, maintenance of crop genetic resources also plays a role in the ability of farmers to adapt to environmental and market uncertainty Almekinders and Louwaars, , and references therein , which may suggest why Cambodian farmers reported higher varietal diversity than their Vietnamese counterparts in both the bi-national and subnational surveys. Varietal identity in our study was based on farmer perceptions, and not confirmed genetically. The mixing of several different stake sources by all traders interviewed likewise suggests that single fields planted with varietal mixes may be common, with unknown effects on exchange behavior.
In other words, highly efficient dissemination networks can translate to equal efficiency in the spread of pests and disease Shaw and Pautasso, ; Patil et al. Depending on the perspective of each actor, given properties of the seed system can often simultaneously be viewed positively or negatively. Informal networks efficiently disseminate the seeds of many crops, including cassava, in diverse contexts Dyer et al. Our findings provide a further example of an informal, yet effective, seed network serving a wide range of farmers, the existence of which had long been suggested by the widespread, spontaneous appearance of Thai and Vietnamese elite cassava varieties across Cambodia Howeler and Ceballos, Trade network structure plays a significant role in plant health epidemics Moslonka-Lefebvre et al.
Even in our single year sample, traders mediated exchanges over a scale of several hundred kilometers. Such networks have powerful reach for scaling uptake and dissemination of introduced germplasm, and potentially knowledge products and extension information, throughout the seed network—but only if actors who leverage trust and social capital are fully engaged. A core strength of informal seed systems, and simultaneous challenge to interventions in their functioning, is the deeply social character and abundance of trust-based interactions.
The importance of personal acquaintances in the present study was complimented by the participation of strangers, especially unacquainted farmers and mobile stake traders. Traders' key roles in connectivity of the seed network may either be highly dependent on social relationships and trust as in Tay Ninh , or purely opportunistic encounters as in Ratanakiri.
Traders therefore assume great importance in seed quality control.onfiregroupinc.com/images/bycifej/serwis-randkowy-dla-samotnych-rodzicw.php
African Seed Enterprises: Sowing The Seeds Of Food Security
Recurrent, reciprocal relationships as described in Tay Ninh may serve as models for the development of acceptable QDS supply to other areas. However, the aforementioned practice of traders mixing stakes from different sources may both compromise varietal purity, and increase the potential distribution of infected materials. In addition to a nearly contiguous cassava production landscape, low crop diversification, low cassava varietal diversity, and frequent off-farm seed exchange increase vulnerability to the spread of pests and diseases. Cassava's lignified outer stem tissues do not exhibit obvious symptoms for a wide range of pathogens Lozano et al.
The absence of certification schemes or quality-declared systems in both Vietnam and Cambodia mean there are currently no available sources for guaranteed clean material for the vast majority of farmers. In the absence of certification and phytosanitary screening mechanisms, farmers at the four subnational sites evaluated planting material quality based on traits associated with germination rather than pest or disease.
The legislative environment for cassava seed systems will play an important role in the development of formal systems as well as interventions into various aspects of informal systems. In Cambodia and Vietnam, the basic policy instruments to guide the development of formal seed systems are in place Table 7. These include delegation of responsibilities for various aspects of seed production and certification to organizations, and distinction of recognized seed certification classes. However, regulations are not commonly applied to cassava seed production, distribution, and reuse of planting materials, all of which predominantly occur outside the sphere of formal seed systems.
Legislation is more consistently applied to rice, maize, and commercial vegetable seed value chains, and generally lacks implementation on vegetatively propagated crops such as cassava. Nevertheless, policies and legislation surrounding cassava seed use will be integral in shaping future policies and projects for preventing and controlling disease spread in cassava seed systems.
In light of emerging phytosanitary constraints in Southeast Asia, our findings indicate several aspects of existing seed systems which require urgent intervention. Conceptions of formal and informal seed systems are not antithetical, but rather possess complementary strengths and weaknesses with potential synergies Almekinders and Louwaars, Seed systems are not binary, but span a complex range of elements combining into adapted, functional systems driven by the changing needs and demands of stakeholders.
Interventions should therefore attempt to build systematically on the strengths of existing seed systems wherever possible to maximize impact.
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Several key interventions are suggested for Vietnam and Cambodia's cassava seed systems based on the results of the present study. The dominance of farm-saved seed and farmer-to-farmer exchange in our study starkly contrasted with low levels of awareness of pest and disease, and few strategies in place to ensure farmer access to quality seed and prevent exchange of infected materials. Education campaigns should promote improved seed production practices at the farm level to reduce seed degeneration rates and eliminate the re-use or exchange of contaminated stakes.
The importance of neighbors as seed suppliers in the present study underscores the need for mass outreach promoting practical approaches which can help to reduce disease pressures; for example positive and negative selection have been shown to increase root yields in susceptible cultivars under cassava mosaic disease pressure Mallowa et al. This strategy has potential for significant impact in areas where use of self-saved seed dominates. Farmer-based associations, not mentioned by respondents in the current study, could also become key actors in cassava stake production in Vietnam and Cambodia's decentralized intra-commune exchange systems through schemes such as multiplication and sale of QDS at the local level Legg et al.
Network analysis enables modeling of likely origins and the anticipated movement of detected pathogens, while a more complete representation of the entire network can also provide predictions of potential multi-step paths through the system. Anticipating multiple steps can be important when cryptic symptoms and long latent periods complicate immediate detection of a pathogen, such that detection may imply that the pathogen has already spread further. Before a pathogen has been detected in a region, the structure of a network suggests the most important locations to detect a new invasion.
Nodes in seed networks which are important hubs having many links or bridges linking otherwise separate locations for the spread of pathogens are likely priorities for both sampling and mitigation. Locations that are not hubs or bridges may still be at high risk for infection, if they are close to such nodes in the network.
Cambodia's Northwestern provinces are a growing, highly connected cluster with distant incoming links, and should receive focused attention for monitoring and containment. The high-intensity production areas of Southern Vietnam are home to a well-developed trader network with a corresponding risk of rapid spread, and should similarly be a focus for preventative measures, dissemination of mitigation strategies, and eventually the release of resistant varieties. Risk assessment is strengthened by incorporating other important risk factors, such as weather conduciveness to disease and pest reproduction.
In contrast to Northwestern Cambodia, Vietnam's Northern provinces are relatively isolated, in combination with low suitability for key pests including the cassava mealybug Phenacoccus manihoti , Yonow et al. The combination of limited regional network connectivity, low potential for B. As phytosanitary pressures on cassava increase Graziosi et al. Formal production pipelines are often linked to public breeding programs or specific projects, and monitor quality in terms of varietal purity, disease control, and physiological age.
Fostering resilience in cassava seed systems will require cooperation with traders to bridge formal and informal systems McGuire and Sperling, , and to expand the reach of clean seed initiatives, extension, and disease monitoring. Links between the existing seed system and crop breeding networks which can supply sources of resistance will also prove important for long-term pathogen management Garrett et al.
Facilitating these interactions will require some acknowledgment of the large international trade pathways of cassava seed in Southeast Asia. Considering industry's central role in root trade and the reciprocal activity of root and seed movement, increased involvement of private sector actors, including root processing factories and purchase points, could be impactful in promoting and scaling the use of quality seed. Organizations of cassava processors and industry members exist both in Thailand and Vietnam, and in the former are already engaged in domestic seed multiplication.
These existing operational models should be further studied and lessons drawn from their experiences. Seed regulations are often designed with commercial systems in mind Spielman and Kennedy, , and when applied to informal seed systems may discourage transparency. Engaging with informal seed networks from an exclusively punitive legislative perspective would prove counterproductive Wattnem, The potential for adapting such approaches to vegetative crops merits further study.
[PDF] African seed enterprises: sowing the seeds of food security. - Semantic Scholar
Seed systems in Vietnam and Cambodia's key cassava production areas were informal and self-regulated, with no active quality certification schemes. Traders played important roles in long-distance seed movement, yet in terms of predominant practice, transaction, and volumes, the use of farm-saved seed and exchanges among acquaintances within the community were most common. However, full understanding of the trader network requires further study. However, high-intensity production areas such as Tay Ninh and Battambang supply long-distance, trader-mediated exchange.
No outgoing exchanges from Cambodia were reported. Planned interventions in cassava seed systems should take into account the established relationships of informal actors including traders, root collection point owners, and starch factory owners and their relationships with farmers, and explore opportunities to empower their current roles in the seed network for phytosanitary monitoring, seed system upscaling, and farmer education campaigns.
Combining seed network analysis with biophysical, epidemiological, and seed market evaluation can guide the design of effective interventions based on these existing networks. Policies and regulations for more formal cassava seed systems do exist. However, innovations should be sought to increase the volume of available quality seed in light of emerging seed-borne pests and diseases.
Models from other crops and contexts should be evaluated for adaptation, such as the use of QDS, positive and negative selection, and seed clubs. Respondents provided oral informed consent prior to survey implementation, and all identifying data were anonymized in the resulting dataset. Participants in the bi-national survey, for whom plant tissue was also collected for SLCMV diagnostics, also provided written consent. KA and KG reviewed the manuscript and provided additional inputs.
All authors reviewed and approved the final manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Almekinders, C. The importance of the farmers' seed systems in a functional national seed sector. New Seeds 4, 15— Local seed systems and their importance for an improved seed supply in developing countries.
Euphytica 78, — Alvarez, E. Andersen, K. Modeling epidemics in seed systems to guide management strategies: the case of sweetpotato in Northern Uganda. BioRxiv [Preprint]. CrossRef Full Text. ASF Access to Seed Index Report Bentley, J. Van Mele, J. Bentley, and R. Buddenhagen, C. Epidemic network analysis for mitigation of invasive pathogens in seed systems: potato in Ecuador. Phytopathology , — Campo, B.
Threats to cassava production: known and potential geographic distribution of four key biotic constraints. Food Security 3, — A simple hydroponic hardening system and the effect of nitrogen source on the acclimation of in vitro cassava Manihot esculenta Crantz. In Vitro Cell. Plant 53, 75— Ceballos, H. Campos and P. Caligari Springer; Springer International Publishing , — Conventional breeding, marker-assisted selection, genomic selection and inbreeding in clonally propagated crops: a case study for cassava.
Yadav, R. Redden, J. Hatfield, H. Lotze-Campen, and A. General rules for managing and surveying networks of pests, diseases, and endangered species. Christinck, A. Table of Contents 1.
Fatal gaps in seed security strategy
Introduction: A full granary 2. How seed works 3. Cameroon: Revolving funds make a difference 4. Nigeria: Clustered seed companies 5. Mali: When government gives entrepreneurs room to grow 6. Guinea: Networks that work 7. The Gambia: Capturing the media 8. Morocco: The visible hand 9. Kenya: A company, a cooperative and a family Uganda: Dreams of starting a company Madagascar: coping with relief aid and politics Conclusions Customer Reviews Average Review.
See All Customer Reviews. Shop Books. Add to Wishlist. USD Sign in to Purchase Instantly. Overview In most developing countries, good quality seed is hard to obtain and farmers struggle to save seed from one year to the next. Average Review.