Characterizing cassava farmer typologies and their seed sourcing practices to explore opportunities for economically sustainable seed business models in Rwanda

The overdependency on local cassava varieties and informal seed sources by farmers in Rwanda has contributed to the spread of cassava viral diseases. The use of improved planting materials made available through formal seed sources, that assure seed quality, is one way to prevent future disease outbreaks. In order to increase the availability of, and farmers access to, such materials there is increasing interest to develop seed business models. This study aims to understand seed sourcing practices of different farm typologies to inform the development of tailored seed business models. A total of 390 farmers were interviewed and the collected data was analyzed into clusters, resulting in seven farm typologies. Seed sourcing strategies, seed replacement dynamics and purchasing behavior of these typologies were explored via a seed tracing study. We find that more commercial oriented farmers have better access to formal seed sources. Nevertheless, the majority of farmers in all typologies accessed new varieties and quality cassava seed via informal channels. At both formal and informal sources, cash investments in seed were mainly made by the categories of better-off farmers, and were one-time investments to acquire a new variety. Based on farmers current seed sourcing practices, clarifications on the differences between farmers and their willingness-to-pay, the roles of seed degeneration, cost-benefit analysis, value propositions and profit formulas seem important requirements for the further development of viable cassava seed business models. We conclude that tailoring seed business models can have a high potential as it acknowledges differences among farmers, but that careful coordination is needed to ensure that one approach or intervention does not contrast with and/or undermine the others.

Phenological Variation in Bluebunch Wheatgrass (Pseudoro-Egneria Spicata): Implications for Seed Sourcing, Harvest, and Restoration

To reduce maladaptation in cultivated seed lots, seed transfer zones (STZs) have been developed for grasslands and other habitats using morphological traits and phenological measurements that only capture the first day of events such as flowering and seed ripening. Phenology is closely linked to plant fitness and may affect genetic loss during harvests of seed raised for ecological restoration. Here, we measured the detailed phenologies of 27 populations from six STZs of bluebunch wheatgrass (Pseudoroegneria spicata) (Pursh) Á. Löve (Poaceae) raised in a common garden to test whether existing STZs created using a combination of plant morphology and “first-day” phenological measurements adequately capture population-level variation in season-long, detailed phenologies. We also used detailed phenologies to test whether genetic losses may occur during single-pass harvests of commercial seed. Mixed and random effect models revealed differences in detailed reproductive phenology among populations within two of six STZs. The number of individual plants within an STZ not producing harvestable seed during peak harvest levels indicated that 10–27% of individuals from a seed lot could be excluded from a single-pass harvest. Although our findings generally support current STZ delineations for P. spicata, they point to the possible precautionary importance of sourcing from multiple populations and harvesting with multiple passes when resources permit.

Gender Roles in Sourcing and Sharing of Banana Planting Material in Communities with and without Banana Bunchy Top Disease in Nigeria

Banana bunchy top disease (BBTD) is the most devasting disease of banana and plantain (Musa spp.). The disease spreads through the use of infected vegetative propagules and the banana aphid (Pentalonia nigronervosa) is the virus vector. This study seeks to understand the gender dimensions and sociocultural aspects of banana seed (vegetative propagule) sourcing and sharing practices among men and women farmers, and its influence on BBTD spread and disease control efforts. Data were collected from 300 banana farmers (187 men and 113 women) in BBTD and non-BBTD areas in southwest Nigeria. The results revealed that seed sharing within the communities is a social responsibility with members expected to share banana seed with the needy mainly as gifts rather than sold for cash. Men farmers mostly sourced seed from old fields, while women sourced seed from relatives. Harvesting of banana seed was predominantly the responsibility of men with women as helpers. Both men and women farmers in the non-BBTD area cultivated larger farm sizes and harvested more banana planting material than farmers in the BBTD area. The existing seed sourcing practices among men and women farmers heighten the risk of BBTD spread. Awareness raising on disease spread through infected seeds should consider gender-differentiated roles and social practices to reduce its spread within communities.

Initial Investment in Diversity Is the Efficient Thing to Do for Resilient Forest Landscape Restoration

The genetic diversity, quality and suitability of seeds and planting stock is crucial for the short and long-term resilience of restored forest landscapes. However, these genetic aspects are widely neglected during both planning and implementation of restoration. Decisions on seed sourcing during implementation of forest landscape restoration (FLR) initiatives often prioritize short-term cost savings over long-term benefits. Such considerations result in strategies that favor rapid and cheap mass production of homogeneous plants and, thus, quantity over quality, with no regard for genetic diversity. This paper explores in detail the economic cost of improved integration of genetic diversity into restoration projects and tests the assumption that the benefits accruing from better integration of diversity exceed the costs. Using a bottom-up cost model, based on peer reviewed scientific literature, we analyse different FLR cost drivers, integrating genetic quality, in relation to the total costs of a range of tree-based restoration interventions, with a focus on seed sourcing, and tree species selection. The results indicate that the integration of genetic diversity into the management and planning of landscape restoration projects increased the costs incurred at the beginning of FLR interventions, specifically during seed sourcing, and species selection. These additional costs were largely due to the increased effort for the collection of genetically diverse and suitably adapted seed lots. However, despite this initial increase in costs the overall costs of restoration decreased substantially, due to cost savings relating to replacement costs of replanting. Even without these savings, the inclusion of genetic diversity is advisable since the costs involved in the integration of diversity are negligible compared to other restoration costs, such as labor costs related to controlling vegetative competition. We conclude that the expected long-term benefits associated with high genetic diversity far outweigh the costs. It also highlights that investing in genetic diversity as part of FLR is the smart thing to do to ensure cost effective and resilient landscape restoration. Restoration policies need to incentivise consideration of genetic diversity.

Reforestation or Genetic Disturbance: A Case Study of Pinus thunbergii in the Iki-no-Mastubara Coastal Forest (Japan)

In the twentieth century, a substantial decline in Pinus thunbergii populations in Japan occurred due to the outbreak of pine wood nematode (PWN), Burshaphelencus xylophilus. A PWN-P. thunbergii resistant trees-breeding project was developed in the 1980s to provide reforestation materials to minimalize the pest damage within the population. Since climate change can also contribute to PWN outbreaks, an intensive reforestation plan instated without much consideration can impact on the genetic diversity of P. thunbergii populations. The usage and deployment of PWN-P. thunbergii resistant trees to a given site without genetic management can lead to a genetic disturbance. The Iki-no-Matsubara population was used as a model to design an approach for the deployment management. This research aimed to preserve local genetic diversity, genetic structure, and relatedness by developing a method for deploying Kyushu PWN-P. thunbergii resistant trees as reforestation-material plants into Iki-no-Matsubara. The local genotypes of the Iki-no-Matsubara population and the Kyushu PWN-P. thunbergii resistant trees were analyzed using six microsatellite markers. Genotype origins, relatedness, diversity, and structure of both were investigated and compared with the genetic results previously obtained for old populations of P. thunbergii throughout Japan. A sufficient number of Kyushu PWN-P. thunbergii resistant trees, as mother trees, within seed orchards and sufficient status number of the seedlings to deploy are needed when deploying the Kyushu PWN-P. thunbergii resistant trees as reforestation material planting into Iki-no-Matsubara population. This approach not only be used to preserve Iki-no-Matsubara population (genetic diversity, genetic structure, relatedness, and resilience of the forests) but can also be applied to minimize PWN damage. These results provide a baseline for further seed sourcing as well as develop genetic management strategies within P. thunbergii populations, including Kyushu PWN-P. thunbergii resistant trees.

Seed Sourcing Strategies Considering Climate Change Forecasts: A Practical Test in Scots Pine

Research Highlights: We experimentally tested different seed sourcing strategies (local, predictive, climate-predictive, climate-adjusted, composite and admixture) under a climate change high emissions scenario using a Scots pine multi-site provenance test. Background and Objectives: There is an urgent need to conserve genetic resources and to support resilience of conifer species facing expected changes and threats. Seed sourcing strategies have been proposed to maximize the future adaptation and resilience of our forests. However, these proposals are yet to be tested, especially in long-lived organisms as forest trees, due to methodological constraints. In addition, some methods rely on the transfer of material from populations matching the future conditions of the sites. However, at the rear edge of the species, some specific problems (high fragmentation, high genetic differentiation, role of genetic drift) challenge the theoretical expectations of some of these methods. Materials and Methods: We used a Scots pine multi-site provenance test, consisting of seventeen provenances covering the distribution range of the species in Spain tested in five representative sites. We measured height, diameter and survival at 5, 10 and 15 years after planting. We simulated populations of 50 trees by bootstrapping material of the provenance test after removing the intra-site environmental effects, simulating different seed sourcing strategies. Results: We found that local and predictive methods behaved better than methods based on the selection of future climate-matching strategies (predictive-climate and climate-adjusted) and those combining several seed sources (composite and admixture seed sourcing strategies). Conclusions: Despite the theoretical expectations, for Scots pine, a forest tree species at its rear edge of its distribution, seed-sourcing methods based on climate matching or a combination of seed sources do not perform better than traditional local or predictive methods or they are not feasible because of the lack of future climate-matching populations.