Seed Management Practices Research Articles

ASSESSMENT OF FARMERS’ KNOWLEDGE AND AWARENESS ON PROPER MANAGEMENT OF FARM-SAVED MAIZE (Zea mays L.) SEEDS IN LAKE ZONE, TANZANIA

Maize farm-saved seeds are characterized by low quality which generally is influenced by managerial practices used by farmers during saving process. A study was conducted to assess farmers’ knowledge and awareness on proper management of maize farm-saved seeds in the Lake Zone of Tanzania. A survey across six regions in the zone was conducted during the 2021/22 cropping season at peak maize planting time. Mixed sampling techniques (multi-stage and purposive sampling) were deployed, whereby 96 farmers who save maize seeds were consulted with an interview using a semi-structured questionnaire to collect information on maize farm-saved seed management practices. Results revealed that 79.2% of farmers obtained seeds from their own saved seeds (own stock). More than 50% of recycled seeds were improved varieties. Above half of farmers were not aware about varieties contamination through crosspollination and mechanical admixture. A minority dry their seeds using inappropriate drying materials. About 37.5% of sampled farmers did not clean their seeds after shelling, and 53.1% store seeds and grains in the same store. The majority are knowledgeable and aware about proper packaging materials. Generally, the majority of farmers managed their farm-saved seeds in improper ways. Therefore, there is a need to improve farmers’ seed management practices so as to improve seed quality or to increase availability and accessibility of seeds from formal system. More research is recommended on maize farm-saved seeds management.

Seed traits inform the germination niche for biodiverse ecological restoration

Seeds are a primary source for generating plants for large-scale restoration and understanding the requirements for seed germination and establishment is fundamental to ecological restoration. Seed germination traits are central to defining the germination niche and identifying traits that may limit seedling establishment provides insights into how seeds may interact with the abiotic environment and the soil substrates specific to each restoration site and informs seed management practices. In this paper we review seed trait data derived from research to improve restoration practice across diverse ecosystems within Western Australia. We compile and evaluate seed trait data for up to 300 seed collections of 287 species that are used in restoration programmes to identify species, lifeform, and region-specific variation in seed dormancy, maximum germination, germination speed, base water potential, and germination niche breadth. Through a synthesis of this data, we outline our ecologically-guided approach to identifying key seed traits that support plant regeneration to improve the success of seed-based restoration across the biodiverse Western Australian landscape.

Cultural Effects on Sorghum Varieties Grown, Traits Preferred, and Seed Management Practices in Northern Ethiopia

Cultural Effects on Sorghum Varieties Grown, Traits Preferred, and Seed Management Practices in Northern Ethiopia. Agrobiodiversity is fundamentally shaped by farmers’ preferences and management practices, and these are again shaped by the farmers’ social and cultural background. This study investigates variety preferences and seed management practices in the crop sorghum (Sorghum bicolor) among the Kunama and the Tigrayan ethnolinguistic groups living side by side in Northern Ethiopia. Surveys were conducted in 10 villages located in two districts inhabited by the two ethnolinguistic groups and analyzed using descriptive and multinominal analysis. We find important differences in varieties grown across the ethnolinguistic groups, but we also find that ethnicity and geographic proximity interact and affect trait preference and seed management practices. Altogether, 22 varieties are cultivated, and few farmers cultivated improved varieties, especially among the Kunama. Respondents considered use traits as important as agronomic traits when selecting sorghum varieties. Notably, preferred use traits were not limited to food (e.g., construction materials were important for the Kunama), and preferred agronomic traits were not focused on drought resistance. Timing of seed selection, seed selection criteria (e.g., panicle size and color), and seed storage practices differed among the ethnic groups. Understanding cultural and social preferences towards sorghum varieties, their traits, and the criteria used for seed management is crucial for the success of crop breeding programs, climate change adaptation policies, and development interventions.

Determinants of adoption of climate smart agricultural technologies among potato farmers in Kenya: Does entrepreneurial orientation play a role?

Climate-smart agriculture (CSA) is an important strategy for supporting farmers against climate change challenges. However, CSA adoption among smallholder farmers particularly in Sub-Saharan Africa (SSA) remains low. This article investigates the factors that influence CSA adoption among smallholder potato farmers in Nyandarua County, Kenya. We specifically focus on the role of the farmers’ entrepreneurial orientation (reflected in the farmers’ innovativeness, proactiveness, and risk-taking), a contribution that has received limited research attention. Data were collected through a cross-sectional survey of 350 potato farming households and analyzed using descriptive statistics, principal component analysis (PCA) and a multivariate probit regression model. Based on PCA analysis, the study considered six categories of CSA practices; soil nutrient management, crop management, crop protection, seed management, water harvesting, and crop quality improvement. The multivariate probit results show that farmers' entrepreneurial orientation had mixed influence on CSA adoption. While farmers’ innovativeness had a positive influence on crop management and improvement practices uptake, its influence on water harvesting technologies was negative. Similarly, proactive farmers were more likely to adopt seed management practices, whereas risk-takers were more likely to adopt protection and water harvesting technologies. Potato producers' willingness to engage in seed multiplication was linked to use of crop protection, seed management, and water harvesting technologies, indicating a path that could help potato farmers’ access clean seed. Other important factors influencing CSA adoption included access to financing through mobile-based applications, gender, land size, trust in extension officers, household income, and farm characteristics. The study discusses the implications of these findings.

Variety and on-farm seed management practices affect potato seed degeneration in the tropical highlands of Ecuador

CONTEXTStudies in the Andes have demonstrated that seed degeneration of potato occurred in experimental conditions, but was negligible in farmers' conditions. There are two hypotheses for this difference: (1) farmers cultivate resistant varieties, or (2) they use on-farm practices that can manage seed degeneration. Farmers may replace some of the seed saved from their fields with outside seed, but it is an open question what level of benefit farmers experience from partial replacement. OBJECTIVESThe objective of this study was to investigate the role of the cultivated varieties, the on-farm seed management practices, and seed replacement in potato seed degeneration. Moreover, this study evaluated the potential effect of partial replacement of the farmers' seed lot each season with healthy seed, compared to less frequent nearly full replacement, in simulations. METHODSWe surveyed farmers in the Cotopaxi province, Ecuador, in 2008, 2010, and 2018, and performed a study on the incidence of pathogens and pests in farmers' seed lots in 2018. We also evaluated the potential effects of the timing of replacement of farmers' seed lots by healthy seed to manage degeneration, applying the seedHealth model. RESULTS AND CONCLUSIONSWe found that farmers experience no or only slow degeneration in their varieties. Analysing yield data reported by farmers to detect degeneration, we did not detect yield declines. The type of variety and year of data collection explained the variation in yield. These results seem to confirm the hypothesis that varieties cultivated in the Andes are resistant to the impact of seed degeneration on yield, and that seed degeneration depends on the agroecological conditions present within a cropping season or year. Because we did not find an impact on yield, we hypothesized that on-farm practices affect seed-borne pathogens and pests causing seed degeneration. We identified multiple on-farm practices playing a role in the process of seed degeneration: they either slowed down or accelerated this process depending on the seed-borne pathogen and pest causing seed degeneration. Our scenario analyses using the seedHealth model showed how replacing farmers' seed lots by healthy seed could usefully reduce seed degeneration compared to using the same amount of seed to periodically replace nearly all seed in a season. Our results showed that on-farm practices are also critical drivers in the process of seed degeneration. SIGNIFICANCEThis study demonstrated the importance of considering on-farm seed management practices (i.e., use of cultivated varieties) to strengthen seed systems interventions aiming to manage potato seed degeneration. Additionally, this study showed the potential of partially replacing farmers' seed with healthy seed as an alternative when complete seed replacement is not an option.

Seed Management and Quality of Farmer Saved Seeds of Bambara groundnut from North Western, Northern and Eastern Uganda


 Bambara groundnut (BG) is a protein and energy-rich legume crop of African origin with the potential to contribute to food and nutrition security. There is limited information on seed man­agement and quality of farmer saved seed of BG in Uganda. This study was conducted to inves­tigate seed management practices and evaluate the quality of farmer saved seed from Uganda. Four hundred BG farmers were chosen using purposive sampling and information gathered on their seed management. A semi-structured questionnaire was used to interview the farm­ers. Seed colour and size determination, standard germination and electrical conductivity tests were done on seed samples collected from farmers. Results from survey revealed that farmers recycled seeds for more than 4 years (39.2%) and maintained mostly single landraces (52.5%). Seed was sun-dried on the ground (81%), stored in gunny bags (93.5%), and threshed mostly by hand (52.0%). Collected landraces had varied seed coat colours and significantly differed at p = 0.05 in their seed sizes, final germination percentage (FGP), electrical conductivity (EC), germination velocity index and seedling vigour index II (SVI-II). Local Bam landrace recorded highest SVI-II (485.3) and EC (0.52MSg-1) while TVSU 688 landrace recorded the highest FGP (96.0%) and lowest EC (0.06MSg-1).

Seed Quality Analysis of Field Pea (Pisum Sativum L.) from Formal and Informal Sources in Enarj Enawuga and Yilmana Densa Districts, West Amhara Region, Ethiopia

The production and productivity of field pea crop in Amhara region depends mainly on the un availability of quality seed supply system for a number of improved varieties. Therefore, this study was conducted to assess the quality and seed management practices of field pea seeds from the informal and formal seed systems in Enarj Enawuga and Yilmana Densa Districts during 2016/17 cropping season.

Organic Manure Seed Pelleting for Enhancing Soil Properties, Nutrient Uptake and Yield of Rice

Background: Seed pelleting involves the sticking of target materials on to the surface of seeds. Pelleted seeds make planting of small seeds much easier by altering their shape, size and density. The call out on organic farming explains the requisite of user friendly and ecofriendly technique for seed management practices. The current study aimed to assess the effect of organic manure seed pelleting for enhancing soil properties, nutrient uptake and yield of rice.Methods: A pot culture experiment was carried out at College of Agriculture, Vellayani during the year 2018-19 to prepare organic manure seed pellets for rice and to evaluate its influence on yield, nutrient uptake and soil nutrient status. Pelleting materials were prepared using various treatment combinations namely, FYM + Azospirillum + Phosphobacteria (T2), vermicompost + Azospirillum + Phosphobacteria (T3), bioslurry flakes + Azospirillum + Phosphobacteria (T4), charcoal powder + Azospirillum + Phosphobacteria (T5), fly ash + Azospirillum + Phosphobacteria (T6), pongamia leaf powder + Azospirillum + Phosphobacteria (T7) and bioslurry + plant extracts + Azospirillum + Pseudomonas (T8: Farmer practice).Result: The results revealed that the highest grain yield (54.84 g pot-1) and straw yield (66.10 g pot-1) were recorded by T3. With regard to the uptake of nutrients, T3 registered the highest uptake of N, K, Ca, S, Zn, Cu and Si in grain and shoot. P uptake in grain was highest in the treatment T4 while T3 had the maximum P uptake in shoot. Nutrient status of the post-harvest soil was significantly influenced by the treatments.

Temporal dynamics of detected transgenes in maize landraces in their center of origin

espanolEl primer reporte sobre maiz transgenico presente en las variedades nativas en su centro de origen se publico en 2001 para Oaxaca, Mexico. Las investigaciones posteriores realizadas en el mismo estado fueron controvertidas: la mayoria de las muestras de maiz analizadas en el periodo de 2001 a 2004 fueron negativas y solo unas pocas muestras resultaron positivas para la presencia de elementos transgenicos en diferentes localidades y anos. El proposito de este articulo es documentar la presencia de maiz transgenico en las regiones terrestres prioritarias (RTP) de Oaxaca y contribuir a la comprension del movimiento del maiz transgenico a traves de las practicas de manejo de semillas. Durante el periodo 2008-2018, se monitorearon 66 municipios y 148 localidades pertenecientes a 3 RTP. Se encuesto a un total de 1,210 agricultores sobre las practicas de manejo del maiz y se obtuvieron 1,412 muestras de maiz nativo que se analizaron mediante metodos moleculares. La presencia adventicia de secuencias transgenicas se detecto en 1.69% de las muestras. Las muestras positivas provinieron de municipios de la sierra de Juarez, Los Loxicha (sierra Sur) y Santa Maria Huatulco en la costa del Pacifico. Las respuestas de los agricultores indicaron que hay un gran movimiento de semillas entre las localidades, pero tambien se introducen semillas de otras areas del pais. Los datos muestran episodios de aparicion y desaparicion de los transgenes, lo que indica un reemplazo espacio-temporal altamente dinamico a lo largo del tiempo, causado principalmente por la introduccion de material externo. Este ultimo aspecto debe ser tomado en cuenta por las autoridades para la regulacion de la introduccion de semillas mejoradas a las comunidades tradicionales donde las variedades locales son la base de su subsistencia. EnglishThe first report of transgenic maize in Mexico was published in 2001 for Oaxaca, Mexico. Subsequent studies were controversial, because most of the maize samples analyzed from different years and localities, were negative. The purpose of this paper is to publish records of the presence of transgenic maize in Priority Terrestrial Regions in Oaxaca, and to contribute to the understanding of the movement of transgenic maize through seed management practices. During 2008-2018, 66 municipalities and 148 localities, belonging to 3 PTRs were monitored. A total of 1,210 farmers were surveyed on practices associated with maize management, and 1,412 maize samples were obtained and analyzed using molecular methods. Adventitious presence of transgenic sequences was detected in 1.69% of the samples. The positive samples came from municipalities belonging to Sierra Juarez, Los Loxicha region, and Santa Maria Huatulco. Farmers’ responses indicated that there is a high movement of seed among localities, but also from other areas of the country. Transgenes appear and disappear, indicating a highly dynamic spatio-temporal replacement over time, mainly due to introduction of foreign material. This aspect must be taken into account to regulate introduction of improved maize to traditional communities.

Genetic Patterns of Common-Bean Seed Acquisition and Early-Stage Adoption Among Farmer Groups in Western Uganda.

Widespread adoption of new varieties can be valuable, especially where improved agricultural production technologies are hard to access. However, as farmers adopt new varieties, in situ population structure and genetic diversity of their seed holdings can change drastically. Consequences of adoption are still poorly understood due to a lack of crop genetic diversity assessments and detailed surveys of farmers' seed management practices. Common bean (Phaseolus vulgaris) is an excellent model for these types of studies, as it has a long history of cultivation among smallholder farmers, exhibits eco-geographic patterns of diversity (e.g., Andean vs. Mesoamerican gene-pools), and has been subjected to post-Columbian dispersal and recent introduction of improved cultivars. The Hoima district of western Uganda additionally provides an excellent social setting for evaluating consequences of adoption because access to improved varieties has varied across farmer groups in this production region. This study establishes a baseline understanding of the common bean diversity found among household producers in Uganda and compares the crop population structure, diversity and consequences of adoption of household producers with different adoption practices. Molecular diversity analysis, based on 4,955 single nucleotide polymorphism (SNP) markers, evaluated a total of 1,156 seed samples that included 196 household samples collected from household producers in the Hoima district, 19 breeder-selected varieties used in participatory breeding activities that had taken place prior to the study in the region, and a global bean germplasm collection. Households that had participated in regional participatory breeding efforts were more likely to adopt new varieties and, consequently, diversify their seed stocks than those that had not participated. Of the three farmer groups that participated in breeding efforts, households from the farmer group with the longest history of bean production were more likely to conserve “Seed Engufu”, a local “Calima”-type variety of the Andean bean gene pool, and, at the same time, introduce rare Mesoamerican gene pool varieties into household seed stocks.

Do smallholder farmer-led seed systems have the capacity to supply good-quality, fungal-free sorghum seed?

Local seed systems that are developed, managed and maintained by farmers are a fundamental practice in smallholder crop production, supporting more than 80% of farmers in sub-Saharan Africa and feeding more than 70% of its population. The resilience of such systems is under threat from poverty, climate change, drought, increased pests and diseases, over-promotion of modern crop varieties, change of lifestyles and restrictive seed policies. The system continues to be maligned as having inferior quality, yet few studies support this assertion. This study aims to fill this research gap by evaluating 60 sorghum seed samples collected from smallholder farmers in Uzumba-Maramba-Pfungwe and Chimanimani districts of Zimbabwe. We investigated the effect of farmer-led seed management practices (e.g. seed acquisition and seed storage practices) on farm-derived sorghum seed quality (moisture, germination and fungal incidences). We found farmers using diverse seed sources and seed storage practices. Seeds were typically of good quality in that their storage moisture content was low, their germination was high, and fungal incidences were low. Seed sourced from local markets, non-governmental organizations and other farmers had germination and moisture standards that met the sorghum certification standards in Zimbabwe. However, few samples obtained from the relatives and government failed to meet the germination and/or moisture certification standards. We detected low incidences of fungi (Aspergillus flavus, Aspergillus niger, Curvularia lunata, Fusarium sp. and Penicillium sp.) in sorghum seed samples tested and in particular Fusarium sp., which is the most economic important fungus in sorghum production. We conclude that farmer-led seed systems have the capacity to supply seeds of good quality and recommend that such systems should be recognized and promoted to meet the ever-evolving needs of smallholder farmers in sub-Saharan Africa.

Transgene flow in Mexican maize revisited: Socio-biological analysis across two contrasting farmer communities and seed management systems.

The flow of transgenes into landraces and wild relatives is an important biosafety concern. The case of transgene flow into local maize varieties in Mexico (the center of origin of maize) has been intensively debated over the past 15 years, including legal, political, and environmental disputes fanned by the existence of a significant scientific controversy over the methods used for the detection of transgenes. The use of diverse approaches and a lack of harmonized methods specific to the detection and monitoring of transgenes in landraces have generated both positive and negative results regarding contamination of Mexican maize with genetically modified material over the years. In this paper, we revisit the case of transgene contamination in Mexican maize and present a novel research approach based on socio‐biological analysis of contrasting communities and seed management systems. Two communities were used to investigate how different social and biological factors can affect transgene flow and impact transgene spread in Mexico. Our results show the presence of transgenes in one community and thus support the position that transgenes are highly likely to be present in Mexican maize landraces. However, our work also demonstrates that the extent and frequency with which transgenes can be found will significantly depend on the societal characteristics and seed management systems of the local communities. Therefore, we argue that future analysis of transgene presence should include social research on the seed management practices in the sampling area so that more robust and comprehensive understandings and conclusions can be drawn.

Incomplete Infection of Secondarily Infected Potato Plants - an Environment Dependent Underestimated Mechanism in Plant Virology.

The common assumption in potato virus epidemiology is that all daughter tubers produced by plants coming from infected mother tubers (secondary infection) will become infected via systemic translocation of the virus during growth. We hypothesize that depending on the prevalent environmental conditions, only a portion of the daughter tubers of a plant that is secondarily infected by viruses may become infected. To test this hypothesis experimental data from standardized field experiments were produced in three contrasting environments at 112, 3280, and 4000 m a.s.l. in Peru during two growing seasons. In these experiments, the percentage of infected daughter tubers produced by seed tubers that were infected with either potato potexvirus X (PVX), potato Andean mottle comovirus (APMoV), potato potyvirus Y (PVY) (jointly infected with PVX) or potato leafroll luteovirus (PLRV) was determined. Incomplete autoinfection was found in all cases, as the percentage of virus infected daughter tubers harvested from secondarily infected plants was invariably less than 100%, with the lowest percentage of infection being 30%. Changing the growing site to higher altitudes decreased autoinfection for all viruses. Therefore, the assumption of complete autoinfection of secondarily infected plants were rejected, while the hypothesis of environmentally dependent incomplete autoinfection was accepted. The findings help explain the occurrence of traditional seed management practices in the Andes and may help to develop locally adapted seed systems in environments of the world that have no steady access to healthy seed tubers coming from a formally certified seed system. The results obtained almost three decades ago are discussed in light of most recent knowledge on epigenetic regulation of host plant – virus interactions which allow for speculating about the underlying biological principles of the incomplete autoinfection. A research roadmap is proposed for achieving explicit experimental proof for the epigenetic regulation of incomplete autoinfection in the pathosystem under study.

Anchoring durum wheat diversity in the reality of traditional agricultural systems: varieties, seed management, and farmers' perception in two Moroccan regions.

BackgroundTraditional agrosystems are the places were crop species have evolved and continue to evolve under a combination of human and environmental pressures. A better knowledge of the mechanisms underlying the dynamics of crop diversity in these agrosystems is crucial to sustain food security and farmers’ self-reliance. It requires as a first step, anchoring a description of the available diversity in its geographical, environmental, cultural and socio-economic context.MethodsWe conducted interviews with farmers cultivating durum wheat in two contrasted traditional agrosystems of Morocco in the Pre-Rif (163 farmers) and in the oases of the Atlas Mountains (110 farmers). We documented the varietal diversity of durum wheat, the main characteristics of the farms, the farming and seed management practices applied to durum wheat, and the farmers’ perception of their varieties.ResultsAs expected in traditional agrosystems, farmers largely practiced diversified subsistence agriculture on small plots and relied on on-farm seed production or informal seed exchange networks. Heterogeneity nevertheless prevailed on many variables, especially on the modernization of practices in the Pre-Rif region. Fourteen (resp. 11) traditional and 5 (resp. 3) modern varieties were identified in the Pre-Rif region (resp. in the Atlas Mountains). The majority of farmers grew a single variety, and most traditional varieties were distributed in restricted geographical areas. At the farm level, more than half of the varieties were renewed in the last decade in the Pre-Rif, a more rapid renewal than in the Atlas Mountain. Modern varieties were more prevalent in the Pre-Rif region and were integrated in the traditional practices of seed production, selection and exchange. They were clearly distinguished by the farmers from the landraces, the last ones being appreciated for their quality traits.ConclusionsThe surveyed traditional agrosystems constitute open, dynamic and heterogeneous entities. We suggest that competing factors could favour or limit the cultivation of improved varieties and the erosion of original durum wheat diversity. This first description opens the way to focused further investigations, including complementing variety names with cultural, genetic and phenotypic information and unravelling the multidimensional factors and consequences of modern variety adoption.

English

Samples of saved barley (Hordeum vulgare) seed were collected at sowing and threshing time from mid-altitudes and highlands of southern Ethiopia in 2009, and were examined in the laboratory and field condition to determine the status of seed quality. The seed samples included farmers’ cultivar ‘Horsiso’ (two-rowed), ‘Nuro’ and ‘Melo’ (six-rowed). This study revealed that saved barley seeds were not vulnerable to insect pests. However, Alternaria, Aspergillus, Cladosporium. Epicoccum, Fusarium, Helminthosporium, Penicillium, Trichoderma, Trichothecium spp. and Ustilago hordei were detected. The seed samples collected at sowing showed lower standard germination (SG) and higher electrical conductivity (EC). All cultivars had SG above 80%, nevertheless field emergence index (FEI) showed 15.22 up to 37.35%, which is less than the ideal plant population. This indicates differences among cultivars in seed quality deterioration during storage. SG was positively correlated (r = 0.678) with field emergence (FE); EC showed a negative correlation with FE (r = -0.347) and SG (r = -0.233). In conclusion, farmers’ saved seed was found to be low in quality. Therefore, farmers’ seed management practices need to be improved to retain the seed quality and enhance productivity.   Key words: Field emergence index, fungi, germination, seed health.

Modern maize varieties going local in the semi-arid zone in Tanzania.

BackgroundMaize is the most produced crop in Sub-Saharan Africa, but yields are low and climate change is projected to further constrain smallholder production. The current efforts to breed and disseminate new high yielding and climate ready maize varieties are implemented through the formal seed system; the chain of public and private sector activities and institutions that produce and release certified seeds. These efforts are taking place in contexts currently dominated by informal seed systems; local and informal seed management and exchange channels with a long history of adapting crops to local conditions. We here present a case study of the genetic effects of both formal and informal seed management from the semi-arid zone in Tanzania.ResultsTwo open pollinated varieties (OPVs), Staha and TMV1, first released by the formal seed system in the 1980s are cultivated on two-thirds of the maize fields among the surveyed households. Farmer-recycling of improved varieties and seed selection are common on-farm seed management practices. Drought tolerance and high yield are the most important characteristics reported as reason for cultivating the current varieties as well as the most important criteria for farmers’ seed selection. Bayesian cluster analysis, PCA and FST analyses based on 131 SNPs clearly distinguish between the two OPVs, and despite considerable heterogeneity between and within seed lots, there is insignificant differentiation between breeder’s seeds and commercial seeds in both OPVs. Genetic separation increases as the formal system varieties enter the informal system and both hybridization with unrelated varieties and directional selection probably play a role in the differentiation. Using a Bayesian association approach we identify three loci putatively under selection in the informal seed system.ConclusionsOur results suggest that the formal seed system in the study area distributes seed lots that are true to type. We suggest that hybridization and directional selection differentiate farmer recycled seed lots from the original varieties and potentially lead to beneficial creolization. Access to drought tolerant OPVs in combination with farmer seed selection is likely to enhance seed system security and farmers’ adaptive capacity in the face of climate change.

Farmers' common bean variety and seed management in the face of drought and climate instability in southern Ethiopia

This study reports the various elements and contexts that characterize the farmers’ use and management of common bean seed and varieties in southern Ethiopia. The study used focus group discussions, contact-farmer interviews and surveys. The results demonstrate that farmers’ cropping systems and preferences vary strongly. Moreover, the high level of environmental variation and the associated risks of crop failure have increased even more with climate instability. While farmers are aware of climate instability, only about half of them have adapted some cropping practices to better cope with it. Simultaneously, markets offer different opportunities and common bean production expands in areas at slightly higher elevation. In these conditions, common bean production is increasingly important for farmers. They currently manage only modest levels of bean crop diversity. Farmers’ variety and seed management practices do not show a high level of specialization and at the same time the use of off-farm seed sources is relatively high. This situation provides opportunities for strategic development and introduction of common bean genetic diversity. Earlier maturing, more drought-tolerant common bean varieties for a range of conditions, markets and preferences should be developed with an integrated understanding of farmers’ production conditions and existing seed system practices.

Inexplicable or simply unexplained? The management of maize seed in Mexico.

Farmer management of plant germplasm pre-dates crop domestication, but humans’ role in crop evolution and diversity remains largely undocumented and often contested. Seemingly inexplicable practices observed throughout agricultural history, such as exchanging or replacing seed, continue to structure crop populations across the developing world. Seed management practices can be construed as events in the life history of crops and management data used to model crop demography, but this requires suitable quantitative data. As a prerequisite to addressing the causes and implications of maize seed management, we describe its patterns of variation across Mexico by drawing from the literature and new analysis. We find that rates of seed replacement, introduction and diffusion differ significantly across regions and altitudinal zones, but interactions among explanatory factors can obscure patterns of variation. The type, source, geographic origin and ownership of seed help explain observed rates. Yet, controlling for the characteristics of germplasm barely reduces interregional differences vastly exceeding variation across elevations. With few exceptions, monotonic altitudinal trends are absent. Causal relationships between management practices and the physical environment could determine farmers’ wellbeing and crop conservation in the face of climate change. Scarce and inconsistent data on management nevertheless could prevent an understanding of these relationships. Current conceptions on the management and dynamics of maize diversity are founded on a patchwork of observations in surprisingly few and dissimilar environments. Our estimates of management practices should shed light on differences in maize population dynamics across Mexico. Consistency with previous studies spanning over a decade suggests that common sets of forces are present within large areas, but causal associations remain unknown. The next step in explaining crop diversity should address variation in seed management across space and time simultaneously while identifying farmers’ values and motivations as underlying forces.

New Genes in Traditional Seed Systems: Diffusion, Detectability and Persistence of Transgenes in a Maize Metapopulation

Gene flow of transgenes into non-target populations is an important biosafety concern. The case of genetically modified (GM) maize in Mexico has been of particular interest because of the country’s status as center of origin and landrace diversity. In contrast to maize in the U.S. and Europe, Mexican landraces form part of an evolving metapopulation in which new genes are subject to evolutionary processes of drift, gene flow and selection. Although these processes are affected by seed management and particularly seed flow, there has been little study into the population genetics of transgenes under traditional seed management. Here, we combine recently compiled data on seed management practices with a spatially explicit population genetic model to evaluate the importance of seed flow as a determinant of the long-term fate of transgenes in traditional seed systems. Seed flow between farmers leads to a much wider diffusion of transgenes than expected by pollen movement alone, but a predominance of seed replacement over seed mixing lowers the probability of detection due to a relative lack of homogenization in spatial frequencies. We find that in spite of the spatial complexities of the modeled system, persistence probabilities under positive selection are estimated quite well by existing theory. Our results have important implications concerning the feasibility of long term transgene monitoring and control in traditional seed systems.

Farmers' Seed Sources and Seed Quality: 1. Physical and Physiological Quality

Understanding farmers' seed quality problem will enable farmers to devise strategies to improve quality at the farm level. The study was conducted to assess the quality of seed used by farmers from different sources and regions. A total of 304 wheat (Trticium aestivum L. and T. durum L.) seed samples from Ethiopia and 206 wheat and 200 barley (Hordeum vulgare L.) seed samples from Syria were collected from major wheat and barley growing regions to investigate the quality of seed obtained from various sources and regions and planted by farmers. A 1 kg sample was drawn from seed lots intended for planting from each farmer. A detailed questionnaire was used to collect information on seed selection and management practices and farmers' perception of seed quality. The physical and physiological quality of seed samples was analyzed using standard testing procedures. In Ethiopia, the mean physical purity and germination of wheat seed was 98.92% and 96%, respectively, and the majority of samples (93%; n = 303) met the minimum purity and germination standards for certified seed 2. Certified seed from the formal sector seed had the highest analytical purity (99.4%), but this was not significantly different from other seed sources, such as neighbors/other farmers (98.8%), local traders/markets (98.6%), or own saved seed (98.9%). However, the mean germination for certified seed (96%) showed a weak significant difference from seed obtained from other sources (94%). In Syria, mean physical purity and germination for wheat was 97.6% and 88%, respectively, and for barley 95.5% and 86%, respectively. Seed quality was better in wheat than in barley. The majority of wheat seed samples, i.e., 70.4% (n = 206) for physical purity and 78.2% for germination, met the minimum seed quality requirements of certified seed 2. In barley, only 10% of samples for physical purity and 72% of samples for germination met this standard. Contamination with weed seeds appeared to be the major constraint for seed samples not meeting the standard of formal sector. There was no significant difference in physical and physiological quality of wheat seed samples obtained from different sources. In barley, germination from different sources was significantly different. Highly significant differences in seed quality were observed for seed samples collected from different regions and districts for wheat and barley crops in both countries. Vigor indices showed significant differences among wheat and barley seed samples from different regions and districts, but not among different sources. Simple correlation coefficients showed significant relationships among vigor tests. The standard germination, speed of germination, and seedling root length were well correlated with field emergence in wheat and barley in both countries. Farmers used local seed management practices, such as seed selection, cleaning, treatment, or separate storage to improve or maintain seed quality. A large number of seed samples managed differently by farmers met the minimum physical purity and germination standard for certified seed 2, producing seed comparable to those from the formal sector. It is imperative that national seed polices equally recognize the role of both formal and informal sectors and provide support to create an integrated seed system catering to the needs of a diverse group of farmers.