Edited by: Stephen Whitfield, University of Leeds, United Kingdom
Reviewed by: Conny Almekinders, Wageningen University & Research, Netherlands; Katrien Descheemaeker, Wageningen University & Research, Netherlands
This article was submitted to Climate-Smart Food Systems, a section of the journal Frontiers in Sustainable Food Systems
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Farmer seed systems are considered pivotal to adaptation to climate change and the on-farm conservation of agrobiodiversity in centers of crop origin. To better understand their distinct role, we conducted a multipronged analysis of potato seed exchange networks in Peru's central Andes distinguishing between cultivar groups and farmer types following cropping seasons with and without acute stress. Cultivar groups involved (i) bred varieties, (ii) commercial floury landraces, (iii) non-commercial floury landraces (single cultivars), (iv) non-commercial floury landraces (mixed cultivars), and (v) bitter landraces. Farmer types involved (i) general farmers, (ii) seed specialists, and (iii) custodian farmers. Documentation of seed acquisition and provision without differentiating between farmers and cultivar groups may not accurately reflect the fine-grained dynamics underlying seed networks. To test this, a semi-structured survey of 336 households was conducted in 2014–2015 to study seed procurement in two research sites. Results confirm that seed networks are uneven and distinct for cultivar groups and farmer types. Commercial floury landraces and bred varieties were dominant when it came to frequency of transactions, volumes and overall availability. Bitter landraces represent an extreme opposite case, being procured infrequently. Non-commercial floury landraces represent an intermediate case as they are regularly procured in comparatively small volumes. The influence of general farmers and traders within seed networks is essential for overall seed access. The role of specialists and custodians is less omnipresent; yet, both fulfill a unique role. Specialists as providers of large volumes of certified seed of commercial floury landraces and bred varieties. Custodians as a source of diverse non-commercial floury landraces. Seed networks did re-organize following seasons with acute seed stress. A notable shift involved a contraction of seed networks within sub-regional clusters. Following stress, the directionality of seed provision vs. acquisition inverted. While average seed volumes acquired per transaction nearly halved, farmers' net seed acquisitions surpassed provisions in response to stress. We suggest that the self-regulatory capacity of farmer seed networks represents a strong safety net through which smallholders can respond to crop failure and seed stress. Seed system interventions aimed at genetic resources conservation or relief should build on these seed networks.
Farmer seed systems across the developing world are recognized as pivotal to food security, nutrition, crop genetic diversity, and resilience in the face of climate change (Badstue et al.,
Drivers underlying seed renewal include crop failure, seed degeneration and varietal change (Scheidegger et al.,
The application of social network analysis is particularly relevant and useful to the study of the seed exchange dynamics underlying crop landrace and genetic diversity (Delêtre et al.,
In the Andes the potato is the backbone of smallholder diets, culture, and economies (Brush et al.,
The notion that farmer seed is of inferior quality has to a certain extent been overcome in Andean countries through its recognition in national legislations and quality declared certification schemes (FAO,
Farmer seed systems sustain the management, reproduction and conservation of landraces in centers of crop origin (Carney,
Potato seed production in the Andes typically involves different types of actors in the formal and informal sectors (Cromwell,
Seed specialists are engaged in the formal system through seed production of bred varieties and commercial floury landraces. They multiply and distribute certified seed following defined quality standards, but also may supply non-certified seed of some potato cultivars. Diversity among seed specialists typically does not exceed five cultivars, a combination of bred varieties and commercial floury landraces. Custodian farmers, on the other hand, are renowned for managing high levels of diversity (Gruberg et al.,
Rainfed cropping in the high Andes is a risk-prone activity with hail, frost, pest and diseases frequently affecting production and leading to crop failure and seed insecurity. Seed stress refers to deficits in farmers' seed stocks as a consequence of crop damage caused by biotic or abiotic stressors. Acute seed stress compromises a household's ability to plant the next season's crop. Chronic seed stress, on the other hand, refers to seed insecurity associated with poverty or resource deprivation (Sperling and Cooper,
A key challenge for smallholders following acute seed stress is access to an adequate supply of seed that meets their desired quality and varietal preferences (Louwaars and Tripp,
Our study specifically examines differences between networks involving seed provision and acquisition across the distinct cultivar groups and farmer types following cropping seasons with stress and without stress. We hypothesize that distinct cultivar groups are characterized by different networks, and that seed networks differ for each farmer type. Discerning network differences at this fine-grained level pursues two significant objectives. In terms of policy applications for seed system development and genetic resources conservation, detailed insights can help identify priorities and possible entry points to enhance smallholder seed access to the distinct cultivar groups. Additionally, it can aid the design of response options that are commensurate with the shocks predicted to increasingly affect farmers' seed systems due to climate change.
This study was conducted in two sites with distinct socioeconomic and agricultural risk profiles (Figure
The two study sites: Pasco-Junín border region and Huancavelica region. Map elaborated by Franklin Plasencia, International Potato Center (CIP).
Number of farmer households surveyed by site and farmer type (
1 | Huancavelica, central Andes | Castillapata, Huachhua, Pachacclla, Pumaranra | 10 | 1 | 18 | 1 | 98 | 29 |
2 | Pasco and Junín border, central Andes | Bellavista, Chupaca, Tambillo, Tama, Ulcumayo | 3 | – | 13 | 2 | 126 | 35 |
Total | 13 | 1 | 31 | 3 | 224 | 64 |
The size of the nine communities included in the study ranged from 50 to 300 households. Communities were located between 12 km (nearest) and 50 km (farthest) from weekly markets where farmers, traders and wholesalers buy and sell ware and seed potato. For Pasco-Junín region we included the markets at Paucartambo and Carhuamayo. For Huancavelica region the markets of Paucará, Yauli and the capital city of Huancavelica (Figure
Communities were selected based on multiple criteria, including potato cropping area, cultivar diversity, presence of different farmer types, access to weekly agricultural markets, and finally the approval of field research by local authorities. We excluded communities which did not meet these requirements simultaneously. Three farmer types and five potato cultivar groups were identified for the farmer surveys (Tables 1, 2). Purposive sampling was used to capture information specific to each farmer type: (i) seed specialists, (ii) custodians, and (iii) general farmers. Custodians and seed specialists specifically were identified through the information provided by local farmers, key informants and institutions (municipal government, NGOs). For general farmers, at the household level and independent of gender, we asked for the person in the household who was knowledgeable of tuber seed procurement. Respondents across the three farmer categories were not necessarily the head of household but rather he or she who was either nominated (custodians, seed specialists) or self-identified as being aware of and able to respond our questions regarding seed procurement. Due to the relative scarcity of custodians and seed specialists, sample sizes for these two farmer types were considerably lower, and localities other than the nine core communities were included (Table
We conducted semi-structured surveys with 336 farmers between October 2014 and February 2015. The surveys were carried out in accordance with the guidelines on Research Ethics for the Social Sciences, Humanities and Arts provided by the Central Committee on Research Ethics at the University of Antioquia, Medellín and in collaboration with two research-for-development institutions based in Peru: the International Potato Center (CIP) and the NGO Grupo Yanapai. Ethics approval was not required for this research by the aforementioned institutions or national regulations as it involved human subjects in non-invasive survey procedures. We sought and obtained the approval of community authorities prior to the implementation of the surveys. We described the objectives of the study, the methodology, the oral prior informed consent option, voluntary nature and confidentiality of households participating during a community assembly. Community authorities from the nine communities selected agreed to participate. Households were surveyed only after community-level approval. This is an appropriate procedure due to the non-invasive nature of the questionnaire (inquiry about potato seed) and the Andean context of communal decisions. Consent was sought verbally for persons to participate (yes, no) and this was always respected. Trained local teams implemented the surveys, either in the Quechua language (Huancavelica) or Spanish (Pasco-Junín). Surveys collected both quantitative and qualitative information about the socio-economic conditions of households and seed procurement following cropping seasons with and without acute stress. Farmers self-determined the most recent seasons with and without acute stress, specified the cause of the stress (i.e., frost, hail, late blight, drought), and described seed transactions for each season. Recalled seasons with and without acute stress varied among respondents and did not necessarily represent the same cropping season (year). For each farmer, only one season per stress condition (with / without acute stress) was documented and analyzed. The survey consisted of ten sections: (i) socioeconomic data; (ii) cropping season; (iii) cultivar-level procurement; (iv) seed volumes; (v) specific seed sources and sinks; (vi) social relationship to providers and clients; (vii) seed transaction types; (viii) place (s) of seed transaction; (ix) seed destination/origin; (x) quality guarantee of seed (including certification). For each respondent, every single transaction of seed acquisition and provision was recorded as a separate entry.
To analyze seed procurement (provision + acquisition) and perform social network mapping we structured the data into node (actor) and tie (event of seed exchange or transaction) attributes (Subedi et al.,
Cultivar groups differentiated in farmer surveys.
1 | Bred varieties | From breeding programs; developed with high-yielding and disease-resistant traits; generally planted as single cultivar plots | Yungay, Canchan, Negra Andina, Amarilis, Unica, Liberteña |
2 | Commercial floury landraces | Landraces known to urban consumers; enjoy market demand; often planted as single cultivar plots | Huayro Moro, Peruanita, Chaulina, Camotillo, Tumbay, Amarilla |
3 | Non-commercial floury landraces (single cultivars) | Landraces of high culinary quality to farmers but largely unknown to urban consumers; planted as single cultivar plots | Puqya, Yana Winqu, Chiqchi Pasña, Trajin Waqachi |
4 | Non-commercial floury landraces (mixed cultivars) | Known as |
|
5 | Bitter landraces | Landraces belonging to |
Yana Manua, Yuraq Waña, Qanchillu, Azul Qanchillo, Yana Waña, Yuraq Manua |
Data were transformed into VNA format and analyzed using UCINET 6 and NetDraw version 2.157 (Borgatti,
Seed network maps were created for cropping seasons following years with and without acute stress according to (i) region, (ii) node type, and (iii) cultivar group. Node sizes corresponded to normalized betweenness centrality, indicating their intermediary power.
Descriptive statistical analyses were performed using R statistical computing software version 3.4.1 (R. Core Team,
To characterize farmers' seed exchange behavior, the metric net trade volume was calculated for each farmer and potato cultivar reported in each season (with/without stress) separately by subtracting the volume of potatoes acquired from the volume provided. Only farmers with either positive or negative net trade volumes were used for further analysis since farmers with a zero balance did not engage in seed provision or acquisition for the specific cultivar group and season in question. We observed that for bitter landraces, equal and relatively insignificant volumes were often provided and acquired following seasons with and without stress, therefore data from this cultivar group was disregarded, while the remaining four cultivar groups—bred varieties, commercial floury landraces, non-commercial floury landraces (single cultivars), and non-commercial floury landraces (mixed cultivars)—were chosen for further statistical analysis. Based on their resulting net trade volumes for each cultivar group and season, farmers were classified into two classes: farmers with a negative trade volume were classified as group one, while farmers with a positive net trade volume were classified as group two. Within the same season (e.g., stress), a farmer could have a negative net trade volume for one cultivar group (e.g., bred varieties) but a positive net trade volume for another (e.g., native-floury landrace). Whereas in the other season (e.g., non-stress), that same farmer did not necessarily classify in the same way depending on the cultivar group. Step wise logistic regression was subsequently performed to identify the significant influence of factors such as farmer type (seed specialist/custodian/general farmer), gender (male/female), season (with/without stress), or region (disaggregated into Pasco/Junín/Huancavelica) on the net trade volume classification for each cultivar group. Both backward and forward methods were used for stepwise regression, and the model that yielded the lowest AIC score was selected. A chi-square test was performed to compare the selected model, a model with interactions, and a full model (with all the explanatory variables) and check for significant differences between them. Odds ratio was calculated by exponentiating the confidence intervals and the coefficients of the selected model. All analyses above were performed in R statistical computing software version 3.4.1 (R. Core Team,
To investigate differences in the total procured volumes for cultivars at specific locations, and to compare across seasons (with and without stress), those cultivars whose frequency of occurrence in the dataset was more than or equal to 10 were selected (13/14 cultivars following seasons with /without stress), and the volumes of all procurements for each of those selected cultivars at a specific location (Cultivar-Location) were summed, separately for each season. Cultivar-Location pairs with the highest values (top 50) of total volume procured following seasons with and without stress were visualized in a barplot. The barplot was constructed using package “ggplot2” in R statistical computing software version 3.4.1 (Wickham,
Of the 336 survey respondents, 20.2% were female. The average age of respondents was 42 years for females and 47 years for males. Average household size was 4.4 members. Nearly half (48.8%) of farmers had primary-level education, 23.5% finished secondary school, and 3.0% had post-secondary school education (technical school, agronomy degree). Among male respondents 6.3% had no formal education; among female respondents this proportion was 29.4%. Disaggregated by region, 46.7% of farmers were from Huancavelica, 36.9% from Pasco, and 16.4% from Junín. By farmer type, 85.7% of survey respondents were general farmers, 10.1% were custodians, and 4.2% were seed specialists. Of the 27 farmers that neither acquired nor provided seed following both seasons (with/without stress) 23 were general farmers and 4 were custodians. Final respondent numbers included for further analyses were: 265 (85.8%) general farmers, 30 (9.7%) custodians, and 14 (4.5%) seed specialists.
Most cropping seasons with stress fell between 2007 and 2015 (93.2%) with a few respondents recalling years back to 2000. Cropping seasons without stress pre-dominantly fell between 2009 and 2015 (93.5%) with a few going as far back as 2001. The medians for seasons with/without stress were 2012 and 2013 respectively. Frost was nominated as the stressor leading to seed insecurity in 47.2% of farmer responses, followed by late blight (27.0%), hail (24.3%) and pests and drought (1.5%).
In the years following stress seasons, the number of seed provisions from households in the network decreased by 68% and the number of seed acquisitions increased by 59% compared to seasons without stress. The number of farmers acquiring seed increased by 45% compared to seasons without stress (Table
Number of farmers acquiring and providing seed per farmer type and cultivar group following cropping seasons
Custodian | 10 | 43.5 | 2 | 22.2 | 17 | 73.9 | 6 | 66.7 | 7 | 30.4 | 4 | 44.4 | 3 | 13.0 | 3 | 33.3 | 0 | 0.0 | 0 | 0.0 | 23 | 9 |
General | 86 | 44.1 | 18 | 34.6 | 145 | 74.4 | 31 | 59.6 | 36 | 18.5 | 9 | 17.3 | 25 | 12.8 | 11 | 21.2 | 4 | 2.1 | 1 | 1.9 | 195 | 52 |
Specialist | 5 | 62.5 | 8 | 88.9 | 5 | 62.5 | 6 | 66.7 | 3 | 37.5 | 3 | 33.3 | 1 | 12.5 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 8 | 9 |
Total | 101 | 28 | 167 | 43 | 46 | 16 | 29 | 14 | 4 | 1 | 226 | 70 | ||||||||||
Custodian | 6 | 54.5 | 5 | 31.3 | 8 | 72.7 | 13 | 81.3 | 2 | 18.2 | 6 | 37.5 | 1 | 9.1 | 6 | 37.5 | 0 | 0.0 | 0 | 0.0 | 11 | 16 |
General | 69 | 49.3 | 47 | 32.0 | 105 | 75.0 | 109 | 74.1 | 12 | 9.0 | 26 | 17.7 | 9 | 6.4 | 48 | 32.7 | 0 | 0.0 | 1 | 0.7 | 140 | 147 |
Specialist | 4 | 80.0 | 10 | 76.9 | 4 | 80.0 | 12 | 92.3 | 0 | 0.0 | 4 | 30.8 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 5 | 13 |
Total | 79 | 62 | 117 | 134 | 14 | 36 | 10 | 54 | 0 | 1 | 156 | 176 |
The intensity of transactions was strikingly different depending on the type of cultivar group involved across seasons (Supplementary Material
There was more seed procurement activity when providers and clients lived close to each other and when intermediaries were present. Even in small farmer clusters, intermediaries who acted as seed facilitators enabled the connections for seed acquisition and provision to occur. There were 226 and 176 such clusters, or “2-cliques,” following seasons with and without stress respectively. Hence, a farmer (source or sink) could reach any other in its cluster through two connections. The largest 2-cliques emerged in Pasco-Junín region across seasons. These were a 46-node cluster following seasons with stress and a 38-node cluster following seasons without stress. In both cases, the potato-growing district of Ulcumayo, Junín, acted as a central seed source.
Most farmers were only directly connected to one other farmer. Our analysis of k-cores showed that 79 and 76% of nodes classified as 1-cores following seasons with and without stress respectively. Higher order clusters whereby farmers were connected to two (2-core) and three (3-core) other farmers represented 20 and 1%, and 21 and 3% of farmers following seasons with and without stress respectively.
Most transactions involved cash payments. Following seasons with stress, seed provisions (
Some cultivars were more likely to be sold while others were more likely to be gifted, bartered, or paid-in-kind (Supplementary Material
Institutional donations were minimal and relatively insignificant as a transaction type following both seasons. These involved the commercial floury landraces
The total volume of seed procured (acquired + provided) in the network decreased by 11% following seasons with stress. This difference in volume (−149,386 kg) was not statistically significant (
Average total seed volumes (kg) per household by farmer type and cultivar group following cropping seasons with stress.
Custodian | 10 | 297 | 257 | 2 | 675 | 530 | 17 | 426 | 431 | 6 | 280 | 385 |
General | 86 | 250 | 263 | 18 | 736 | 786 | 145 | 375 | 337 | 31 | 1, 119 | 1, 834 |
Specialist | 5 | 8, 580 | 19, 018 | 8 | 70, 745 | 127, 476 | 5 | 505 | 510 | 6 | 67, 070 | 124, 767 |
Custodian | 7 | 152 | 252 | 4 | 214 | 327 | 3 | 148 | 176 | 3 | 56 | 57 |
General | 36 | 53 | 48 | 9 | 105 | 250 | 25 | 50 | 31 | 11 | 24 | 40 |
Specialist | 3 | 131 | 164 | 3 | 1, 833 | 1, 930 | 1 | 100 | – | – | – | – |
Custodian | – | – | – | – | – | – | ||||||
General | 4 | 28 | 16 | 1 | 12 | – | ||||||
Specialist | – | – | – | – | – | – |
Average total seed volumes (kg) per household by farmer type and cultivar group following cropping seasons without stress.
Custodian | 6 | 350 | 188 | 5 | 2, 088 | 2, 774 | 8 | 770 | 771 | 13 | 929 | 1, 928 |
General | 69 | 279 | 343 | 47 | 1, 035 | 1, 332 | 105 | 564 | 530 | 109 | 1, 210 | 1, 995 |
Specialist | 4 | 13, 200 | 16, 061 | 10 | 5, 7226 | 78, 575 | 4 | 3, 011 | 3, 451 | 12 | 29, 902 | 56, 585 |
Custodian | 2 | 1, 050 | 1, 484 | 6 | 92 | 46 | 1 | 23 | − | 6 | 406 | 730 |
General | 12 | 23 | 18 | 26 | 136 | 234 | 9 | 133 | 137 | 48 | 77 | 92 |
Specialist | – | – | – | 4 | 3, 425 | 3, 305 | – | – | – | – | – | – |
Custodian | – | – | – | – | – | – | ||||||
General | – | – | – | 1 | 6 | – | ||||||
Specialist | – | – | – | – | – | – |
Following seasons with stress, general farmers both acquired and provided lower volumes of seed for all cultivar groups except the bitter landraces. By contrast, the volumes provided by seed specialists increased for bred varieties (+23.6%) and commercial floury landraces (+124.2%). Custodians, on the other hand, presented an increase in the volume provided of non-commercial floury landraces (single cultivars, +132.6%) and volume acquired of non-commercial floury landraces (mixed cultivars, +543.4%). Transactions for bitter landraces were minimum and involved extremely low volumes overall.
We performed logistic regression to characterize influences of season, farmer type, gender and region on net trade volumes (volume provided – volume acquired) for each cultivar group separately (Table
Output of the logistic regression models that were performed to characterize the influence of farmer type (custodian/seed specialist/general farmer), gender (male/female), season (with/without stress), and region (disaggregated into Pasco/Junín/Huancavelica) on net trade volume (volume provided – volume acquired) for the cultivar groups: bred varieties, commercial floury landraces, non-commercial floury landraces (single cultivars), and non-commercial floury landraces (mixed cultivars).
Junín region | 2.07332 | 0.93966 | 4.67758 | <0.1 |
Pasco region | 0.38468 | 0.18015 | 0.80912 | <0.05 |
With stress | 0.22662 | 0.11732 | 0.42147 | <0.05 |
Junín region | 2.16250 | 1.07571 | 4.42959 | <0.05 |
Pasco region | 0.20950 | 0.11365 | 0.37566 | <0.05 |
With stress | 0.10035 | 0.05628 | 0.17214 | <0.05 |
Seed specialist | 7.43888 | 1.78390 | 39.9594 | <0.05 |
Male gender | 2.28556 | 1.12602 | 4.81528 | <0.05 |
With stress | 0.10382 | 0.03876 | 0.25641 | <0.05 |
Junín region | 0.19819 | 0.03602 | 1.01371 | <0.1 |
Pasco region | 0.12706 | 0.03059 | 0.43276 | <0.05 |
With stress | 0.05183 | 0.01374 | 0.15489 | <0.05 |
There were different patterns across the regions. In Pasco region, farmers were net seed acquirers of bred varieties, commercial floury landraces, and non-commercial floury landraces (mixed cultivars). But in Junín, farmers were providers of commercial floury landraces and acquirers of non-commercial floury landraces (mixed cultivars). Huancavelica region did not exert a significant influence on the net trade volume for any cultivar group.
Two bred varieties and two commercial floury landraces had the most significant total volumes procured in the same location (city of Huancavelica) across seasons. Following stress, these volumes nearly tripled (Figure
Barplot contrasting total seed volumes procured (acquired + provided) for a potato cultivar in a specific location (Cultivar-Location pair). The plot visualizes the top 50 Cultivar-Location pairs with the highest values for total procured (acquired + provided) volumes following seasons with and without stress (see section Materials and Methods for more details).
Based on their total seed volumes procured per location, 11 and 12 cultivars made up the bulk, 96 and 95% of total volumes following seasons with and without stress respectively (Figure
We compared the sources and sinks of seed reported by farmers as proportions of total seed acquisitions and provisions across seasons (Tables
Type of seed source/sink reported in surveys, as % of total transactions following cropping seasons with stress.
Family | 4.0 | 3.2 | 5.8 | 6.4 | 3.2 | 1.6 | 1.1 | 1.6 | 0.4 | – | 14.4 | 12.8 |
Friend | 0.9 | 1.6 | 3.7 | 5.9 | 0.5 | 1.1 | 1.2 | 1.6 | 0.2 | – | 6.5 | 10.2 |
Neighbor | 0.7 | 1.1 | 1.6 | 0.5 | 0.9 | – | 0.2 | 2.1 | 0.2 | 0.5 | 3.5 | 4.3 |
General farmer |
1.4 | 4.3 | 9.7 | 10.7 | 1.4 | 5.3 | 0.7 | 2.7 | – | – | 13.2 | 23.0 |
Seed producer |
0.9 | – | 0.7 | – | – | – | – | – | – | – | 1.6 | – |
Trader | 16.0 | 11.8 | 31.2 | 18.7 | 4.0 | 1.1 | 2.1 | 2.1 | – | – | 53.3 | 33.7 |
Government | 1.4 | 3.7 | 2.6 | 3.2 | 0.2 | – | 0.2 | – | – | – | 4.4 | 7.0 |
NGO | – | 1.1 | – | 1.6 | – | 0.5 | – | – | – | – | – | 3.2 |
Other | 0.9 | 3.7 | 1.8 | 1.6 | 0.2 | 0.5 | 0.2 | – | – | – | 3.0 | 5.9 |
Total % | 26.2 | 30.5 | 57.0 | 48.7 | 10.4 | 10.2 | 5.6 | 10.2 | 0.7 | 0.5 | 100.0 | 100.0 |
Type of seed source/sink reported in surveys, as % of total transactions following cropping seasons without stress.
Family | 1.4 | 4.1 | 2.2 | 8.1 | 0.8 | 1.9 | 1.4 | 4.5 | – | 0.2 | 5.9 | 18.7 |
Friend | 0.8 | 1.7 | 1.7 | 4.8 | – | 0.2 | – | 2.7 | – | – | 2.5 | 9.5 |
Neighbor | 1.4 | 1.9 | 0.8 | 2.6 | 0.8 | 0.9 | – | 1.2 | – | – | 3.1 | 6.5 |
General farmer |
2.8 | 5.2 | 15.7 | 11.9 | 0.6 | 2.6 | 0.6 | 2.7 | – | – | 19.6 | 22.3 |
Seed producer |
1.1 | 1.4 | 0.3 | 1.4 | – | – | – | – | – | – | 1.4 | 2.7 |
Trader | 21.0 | 7.7 | 35.3 | 18.9 | 1.7 | 3.4 | 0.8 | 3.3 | – | – | 58.8 | 33.3 |
Government | 2.5 | 1.4 | 4.2 | 2.7 | – | 0.3 | – | – | – | – | 6.7 | 4.5 |
NGO | – | – | – | 0.5 | – | 0.3 | 0.3 | 0.2 | – | – | 0.3 | 1.0 |
Other | 0.3 | 0.7 | 0.6 | 0.5 | 0.8 | 0.2 | – | – | – | – | 1.7 | 1.4 |
Total % | 31.4 | 24.1 | 60.8 | 51.4 | 4.8 | 9.8 | 3.1 | 14.6 | – | 0.2 | 100.0 | 100.0 |
Seed specialists accounted for 13.4% of seed provisions following seasons without stress and 24.1% following seasons with stress. Their role involved trade with government programs and NGOs, more so than other actors who emerged in the network (i.e., traders). The main sinks of seed from specialists were government institutions (32.1%), general farmers (30.8%), and other seed specialists (15.4%). Following seasons with stress they involved government (28.9%), general farmers (28.9%), farmer associations (15.6%), NGOs (13.3%), traders (11.1%), and one mining company. Government institutions, specifically ministries, development programs and municipalities from Huancavelica region, only acquired certified seed from specialists. In the same region, different NGOs also pre-dominantly sourced seed from seed specialists, and smaller volumes from general and custodian farmers. Except for one seed loan to a municipality, all transactions between specialists and government institutions involved sales.
Regional markets also were notable sources and sinks of seed across seasons. Procurement in weekly regional markets represented 33 and 30% of all transactions following seasons with and without stress respectively. Following seasons with stress, seed procurement at markets involved 59% commercial floury landraces, 26% bred varieties, 11% non-commercial floury landraces (single cultivars), and 4% non-commercial floury landraces (mixed cultivars). In the absence of stress, general farmers used these markets to provide seed to other (mostly anonymous) farmers. Following stress, the intensity of these provisions lowered and at a weekly market in Junín (Carhuamayo), the biggest sink across seasons, the number of seed provisions by general farmers dropped by 52% following stress. By contrast, the intensity of seed acquisitions increased following stress. For example, at the weekly Sunday market of Paucará, Huancavelica, the number of seed acquisitions increased by 400% compared to seasons without stress. Along with traders, markets showed the highest betweenness centrality or intermediary influence regardless of season (Figures
Institutional depiction of seed network following cropping seasons
We analyzed the structure of the seed network following cropping seasons with and without stress, and found the networks diminished following stress. Under both conditions the network was composed of two main regional clusters: Pasco-Junín and Huancavelica (Figures
Regional depiction of seed network following cropping seasons
Network cohesion parameters were compared following seasons with and without stress (Table
Network cohesion parameters following cropping seasons with and without stress.
Average degree [Ties] | 1.0111 | 1.0759 | 1.2516 | 1.0916 | 1.2104 |
Out-centralization [Provision] | 0.0982 | 0.0646 | 0.2786 | 0.1853 | 0.0841 |
In-centralization [Acquisition] | 0.0223 | 0.0418 | 0.0621 | 0.0225 | 0.0542 |
Density [Inter-connection] | 0.0023 | 0.0020 | 0.0079 | 0.0084 | 0.0030 |
Average Distance [Steps] | 1.9691 | 2.7623 | 1.5979 | 2.3422 | 2.8200 |
Regardless of the season, the networks were comparably, sparsely connected. The density parameter, or the degree of interconnection and ease of seed / information transfer, was low for both networks and main clusters. This is partly expected considering the size of the network, because it is not possible for all farmers to interact with each other across regions (Ekboir et al.,
Frost, late blight and hail as main causes of acute stress and seed insecurity differ in intensity and range of incidence between seasons. Seed insecurity led to contraction of the network and a disconnect between the main regions studied. The total number of nodes (actors) and ties (transactions) diminished, as did the in-degree, out-degree and betweenness. Following stress, the total number of farmers engaging in seed procurement decreased, the total volumes procured declined, and the directionality of seed provisions vs. acquisitions was inverted. Farmers' net seed acquisitions, as revealed by the analysis of net trade volumes, surpassed provisions in response to stress. Although the average number of transactions for those involved in seed procurement remained roughly the same, the average volume acquired per individual transaction was nearly halved following seasons with stress.
Independent of the type of stress, all farmers surveyed partially restored seed stocks by securing small volume acquisitions from multiple sources. Tapping into local resources including social networks and markets allows for coping capabilities and seed security even in adverse climate-induced crises. Such adaptive capacity has also been reported in other contexts (Mortimore and Adams,
Following stress, seed provisioning concentrated in sub-regional clusters that linked farmers based on geographic proximity. This suggests that seed was locally available and accessible in most cases, a situation that might change when stress is widespread and affecting a whole region (De Haan et al.,
Regardless of the season, seed dealings involved mostly monetary transactions in the marketplaces frequented by farmers. This finding coincides with reports from other contexts where farmer seed systems were also found to be highly market-driven and mediated by cash transactions (McGuire and Sperling,
In Huancavelica region especially,
Farmer seed systems involve ample procurement of bred varieties and commercial floury landraces independent of season and region. On their own, commercial floury landraces accounted for more than half of seed transactions across seasons. The seed procurement networks were dominated by four bred varieties and eight commercial floury landraces in terms of seed volumes traded and presence in multiple transaction locations. Excluding the intraspecific diversity contained in
Non-commercial floury landraces (single and mixed cultivars) showed only modest volumes of seed procurement across seasons. One out of five general farmers and one out of three custodian farmers provided small volumes of non-commercial floury landraces (mixed cultivars). Farmers located in Pasco-Junín region consistently demanded small volumes of mixed non-commercial floury landraces, independent of the season. This finding shows the coexistence of selective cultivar production for the market with landrace diversity (Stromberg et al.,
Interestingly, following stress more farmers turned to non-commercial floury landraces of single and mixed cultivars for seed. Possibly, with a reduced supply of the most common cultivars, farmers' seed choices were constrained to the less popular, non-commercial cultivars that were available in their networks. Another plausible explanation may involve farmers going back to more diverse species and varietal portfolios to spread risk (Meldrum et al.,
General farmers in Peru's central highlands play an important and unique role in the seed network. Unlike studies showing farmer centrality to be determinant for efficient seed distribution (see Ricciardi,
Custodian farmers play a distinct role in the seed system as sources and sinks of relatively small volumes of unique cultivars. They are, in a sense, the primary reservoirs of the intraspecific diversity inherent in
The role of specialized seed producers has been highlighted in other smallholder contexts for their ability to link the informal and formal systems and disseminate new crop varieties in a cost-effective way, albeit involving relatively small seed volumes (Otsyula et al.,
Potato seed networks in Peru's central highlands are to a large extent self-regulatory. Independent of the season, farmers consistently procured seed of different cultivar groups from traders, neighboring farmers, and family, making them regular sources in the seed network. In situations without stress, farmers typically obtain the bulk of their seed on-farm yet access to additional off-farm seed remains important due to farmers' desire to “refresh” stocks of existing varieties or experiment with new cultivars for their agronomic and end-use qualities (Urrea-Hernandez et al.,
Markets are central hubs for seed procurement and involved a third of all transactions, independent of the season. They fulfill a role as social and economic spaces where farmers, traders, and buyers from different locations interact to access seed, inputs and information. In diverse contexts, markets have emerged as pivotal to seed access, security, and stability following stress (Sperling et al.,
Traders are important brokers who facilitate access to seed of all cultivar groups (except bitter landraces) from either renowned geographic locations or seed specialists. Although most seed transactions mediated by traders involved commercial floury landraces and bred varieties across seasons and regions, following stress traders also engaged in regular seed provisions of non-commercial floury landraces (single and mixed cultivars). Despite the seed quality concerns often associated with this group of stakeholders, traders that farmers trust occupy a significant market niche in the informal system and deliver seed through local supply channels in times of seed stress (Bentley and Vasques,
Independent of the cultivar group, trust was fundamental for seed acquisitions and transactions are frequently based on social ties and geographical origin. Such types of informal guarantees have been observed to occur in other cropping and farmer systems (Stromberg et al.,
Formal government participation in the seed networks was modest. These findings are consistent with the weak articulations that have typically characterized the nexus between farmer-based and formal systems in the Andes (Bentley and Vasques,
It has been suggested that studying the seed procurement network over a single year provides a misrepresentation of the dynamics underlying social networks (Violon et al.,
Our main hypotheses were confirmed by our findings. Seed procurement networks are uneven and highly distinct depending on the cultivar group and farmer type. Commercial floury landraces and bred varieties were ubiquitous and dominant in the seed network in terms of their frequency of transactions, volumes exchanged, location occurrences and overall availability. They outweigh the non-commercial floury landraces (mixed and single cultivars) and bitter landraces by far when it comes to regular seed supply and demand. All farmer types engaged in seed procurement of these two cultivar groups. Bitter landraces represent an extreme opposite case, being procured infrequently and nearly invisible in the network. Possible explanations relate to the limited cropping area this special cultivar group occupies and its limited varietal diversity. Changes in Andean livelihoods and food systems, in combination with less predictable dry-season frosts needed to process bitter landraces, have likely led to diminished demand. Seed networks of non-commercial floury landraces (single and mixed cultivars) represent an intermediate situation. They are regularly procured in comparatively small volumes by general and custodian farmers. This is important as most of the potato's varietal diversity is encapsulated within this cultivar group.
The influence of general farmers and traders within seed networks is significant and essential for overall widespread and decentralized access to planting material. Independent of the season, general farmers have the capacity to provide seed of the main cultivar groups. The role of seed specialists and custodian farmers is less omnipresent and versatile. Yet, both occupy a unique role and niche market. Seed specialists as providers of comparatively large volumes and formally certified seed of commercial floury landraces and bred varieties. Custodian farmers as a noteworthy source of uncommon and diverse non-commercial floury landraces. Seed specialists are the only farmer type regularly linking to government institutions. Custodian farmers maintain specific informal networks through which genetic diversity is regenerated and redistributed.
Seed networks did re-organize following seasons with acute seed stress. However, not necessarily as anticipated. Traders and markets remained significant sources and sinks of seed regardless of season. Farmer-recognized geographically-defined sources of seed also remained equally important. In the absence of seed stress farmers still practice partial seed renewal to “refresh” seed stocks of common varieties or to experiment with new cultivars. A significant shift in response to acute stress included a contraction and concentration of seed networks within sub-regional clusters with shorter path length between sources and sinks. This contrasts with other studies (De Haan et al.,
The self-regulatory capacity of farmer seed systems and flexible portfolio of connections intrinsic to its networks clearly represent a strong safety net through which smallholder farmers can adapt to climate change or respond to crop failure and resulting seed stress. However, we cannot ignore its potential vulnerabilities. The farmer seed network is currently dominated by twelve cultivars while bitter landraces are virtually absent. Since intraspecific diversity will be instrumental for climate change adaptation, it remains important to regularly monitor the extent of conservation. Timeline comparisons of seed networks can aid such efforts. From an on-farm conservation perspective, the identification of leverage points to strengthen farmer seed systems and, where needed, build linkages with actors in the formal sector requires integrating farmer demands and creating opportunities for innovations. Multiple interventions that could build on existing farmer seed networks have been proposed. These include biodiversity seed fairs, community seed banks, positive selection, quality declared seed schemes, among others. Future seed relief in the central Andes could also link more effectively to existing farmer seed networks. Government institutions currently only source from seed specialists, but simple adaptations that open opportunities to general farmers may make a big difference.
Building on existing seed networks and their strengths is a clear policy opportunity. Making sure that locally available seed of diverse varietal portfolios and informal provenance link with seed relief interventions is actionable for national and local policy makers. Finally, the finding that seed procurement networks are uneven raises the question of whether such differences also exist for other single crop species in their respective centers of origin. For example for sweet and bitter cassava in the Amazon or paddy and sticky rice in Southeast Asia. Understanding the conservation dynamics of diverse varietal portfolios warrants attention to differential seed systems.
The datasets generated for this study are available in the Dataverse URL:
AA and SdH conceived and designed the study. AA led the development of household surveys, organized the database, performed descriptive statistics and social network analysis. RC supported with survey implementation and data collection. DB carried out statistical analyses and contributed to results interpretation and manuscript revision. AA and SdH wrote the manuscript. All authors read 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.
The authors thank the smallholder farmers and community authorities of Huancavelica, Pasco and Junín who collaborated with us and made this research possible. We are very grateful to Mary Luz Solórzano for assisting us with the training of survey teams and field implementation of the project. We also thank Gordon Prain at the International Potato Center (CIP) for his valuable contributions to the study design, and Genowefa Blundo Canto at the French Agricultural Research Centre for International Development (CIRAD) for providing advice on social network analysis. Thank you to Maria Scurrah from Grupo Yanapai for facilitating the research grant from the McKnight Foundation. We are indebted to Claire Nicklin at the McKnight Foundation for her support of this research project. We thank Kien Tri Nguyen at the International Center for Tropical Agriculture (CIAT-Vietnam) for his data management support. We are grateful to Toss Gascoigne from Econnect Communication for his helpful review of the manuscript.
The Supplementary Material for this article can be found online at: