User guide to experimental auctions of vegetatively propagated seed. RTB User Guide

Experimental auctions are used to understand the value of different products to consumers through estimations of willingness to pay (WTP). This information is valuable for many reasons, from obtaining local prices attached to seed traits to informing seed businesses about acceptable production costs. Experimental auctions do a better job of estimating this than simple questionnaires or surveys. By engaging participants actively, experimental auctions lead to real or hypothetical consequences that make people think and act carefully according to their personal preferences. This user guide provides an overview of different types of experimental auctions and their use in seed system research. The guide discusses the structure of auctions, planning and conducting them, and lessons from the field. Reading this guide will help you to be prepared to design and implement an auction in your own project or intervention

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

Open Access Article; Published online: 30 Nov 2021The 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

User guide to the toolbox for working with root, tuber and banana seed systems. RTB User guide

This user guide to the Toolbox for working with root, tuber and banana seed systems introduces tools to diagnose, evaluate, and improve seed systems of banana, cassava, potato, sweetpotato, and yam. As a whole, these crops are called roots, tubers and bananas, and they are crucial for food security and income generation, especially in developing countries. All of these crops are reproduced vegetatively, from roots, tubers, stems, suckers or vines. This bulky planting material is expensive to transport. Vegetative seed is perishable and (except for potatoes, yams and a few other exceptions) must be planted as fresh as possible, and it is more likely to carry pests and diseases than true seed. Besides these unique challenges, improved seed systems of root, tuber and banana crops give farmers the opportunity to boost their livelihoods by accessing better quality planting material from landraces or improved varieties that are high yielding, resistant to stresses, more nutritious or more responsive to consumer demand

A capacity framework for strengthening science, education and practice of scaling innovation

This concept note is developed by the CGIAR Initiative for Diversification in East and Southern Africa (Ukama Ustawi). It highlights the significance of strengthening capacity in the science and practice of scaling innovation. The lack of a comprehensive and realistic understanding of innovation and scaling processes, coupled with limited scaling knowledge and capacity across individual, organizational and system levels hinder the effective scaling of innovations. Consequently, many promising initiatives fail to reach their full potential and address systemic issues at scale

A Limited Role for Suppression in the Central Field of Individuals with Strabismic Amblyopia.

yesBackground: Although their eyes are pointing in different directions, people with long-standing strabismic amblyopia typically do not experience double-vision or indeed any visual symptoms arising from their condition. It is generally believed that the phenomenon of suppression plays a major role in dealing with the consequences of amblyopia and strabismus, by preventing images from the weaker/deviating eye from reaching conscious awareness. Suppression is thus a highly sophisticated coping mechanism. Although suppression has been studied for over 100 years the literature is equivocal in relation to the extent of the retina that is suppressed, though the method used to investigate suppression is crucial to the outcome. There is growing evidence that some measurement methods lead to artefactual claims that suppression exists when it does not. Methodology/Results: Here we present the results of an experiment conducted with a new method to examine the prevalence, depth and extent of suppression in ten individuals with strabismic amblyopia. Seven subjects (70%) showed no evidence whatsoever for suppression and in the three individuals who did (30%), the depth and extent of suppression was small. Conclusions: Suppression may play a much smaller role in dealing with the negative consequences of strabismic amblyopia than previously thought. Whereas recent claims of this nature have been made only in those with micro-strabismus our results show extremely limited evidence for suppression across the central visual field in strabismic amblyopes more generally. Instead of suppressing the image from the weaker/deviating eye, we suggest the visual system of individuals with strabismic amblyopia may act to maximise the possibilities for binocular co-operation. This is consistent with recent evidence from strabismic and amblyopic individuals that their binocular mechanisms are intact, and that, just as in visual normals, performance with two eyes is better than with the better eye alone in these individuals

Strabismic suppression depends on the amount of dissimilarity between left- and right-eye images

AbstractSuppression in strabismus is more likely to occur when the images for the left- and right-eye are similar. In this study the relationship between the depth of strabismic suppression and the amount of dissimilarity between the images was quantified. Six subjects with microstrabismus looked at two identical colorful, cartoon images via mirrors. In the middle of each screen was a circular aperture with an opal glass, which was illuminated from the back by a halogen lamp during 300 ms with a gradual on- and offset in intensity. In the circular aperture images that slightly differed in shape were presented to both eyes. The dominant eye was presented a circle, the squinting eye a circle that, in four steps, changed its shape into a square. Under each of these four conditions, the image for the dominant eye was attenuated progressively by neutral density filters. When the image for the squinting eye was perceived, the depth of the suppression was thereby measured. It was found that suppression decreased with dissimilarity of the images

Toolbox for Working with Root, Tuber, and Banana Seed Systems

Root, tuber, and banana (RT&B) crops are critical for global food security. They are vegetatively propagated crops (VPCs) sharing common features: low reproductive rates, bulky planting materials, and vulnerability to accumulating and spreading pathogens and pests through seed. These crops are difficult to breed, so new varieties may be released slowly relative to new emerging threats. VPC seed systems are complex and face several challenges: poor-quality seed of existing varieties, low adoption rates of improved varieties, and slow varietal turnover, limiting yield increases and farmers’ ability to adapt to new threats and opportunities. Addressing these challenges requires first identifying key knowledge gaps on seed systems to guide research for development in a holistic and coherent way. Working together across 10 crops and 26 countries in Africa, Asia, and Central and South America, the CGIAR seed systems research community has developed a “Toolbox for Working with Root, Tuber, and Banana Seed Systems,” which introduces 11 tools and a glossary to address four major gaps: (1) capturing the demand characteristics of different types of farmers; (2) identifying effective seed delivery pathways; (3) ensuring seed health and stopping the spread of disease; and (4) designing effective policies and regulations. We describe the toolbox and its creation and validation across 76 crop-and-country use cases, and illustrate how the tools, applied individually or in combination, are addressing the key knowledge gaps in RT&B seed systems. The tool developers are actively working to scale the toolbox, including identifying new partners and models for collaboration, developing new tools, and supporting new applications in VPCs, as well as for fruit, vegetable, grain, and pulse seed systems

Farmers’ demand for quality and nutritionally enhanced sweetpotato planting material: Evidence from experimental auctions in Rwanda

Most farmers source sweetpotato vines from neighboring farmers or from cuttings taken from their own plots during the previous season. In the absence of “clean” vines prepared with more attentive production practices, farmer-to-farmer vine exchanges and own-saved vines tends to encourage the accumulation of pests and diseases that ultimately affect yields. In addition, the perishability and bulkiness of its primary propagation material – vines – there is relatively little articulated demand for vines through either market or non-market exchanges. In addition, demand for nutritionally rich variety and biofortified crop orange-fleshed sweetpotato (OFSP) is limited because of multiple factors including farmers’ unfamiliarity with the product and its novel attributes such as its high beta carotene content, the search costs incurred in locating the product, and information asymmetries between buyer and seller about the quality and performance of the product. We investigate demand for quality vine and nutritional attribute of the crop using a second price experimental auction approach by determine the premium price farmers are willing to pay for these attributes and investigate drivers of demand. In the absence of information on the source of vines, maturity and resistance to diseases, farmers are willing to pay a premium of about 35 Rwandan Francs for high quality vines sourced from decentralized vine multipliers. However, on provision of information on the source of vines, maturity and resistance to diseases of the vines, the premium price increases significantly to 133.71 Rwandan francs and to 107.22 Rwandan Francs after provision of visual information depicting the performance of the vines in demonstration plots. The premium price also increases significantly for vines sourced from neighbors to about 74.35 Rwandan francs, which further increases to 151.53 Rwandan francs when nutrition information is provided to the farmers. The study also revealed that demand for high quality vines is correlated with sex of household head, sex of the respondent, age of the respondent in years, household size, membership in a farmer organization, information from neighbors/other farmers, access to marshland, females make agriculture decisions in the household among other factors. In terms of policy, there is need to promote importance of quality vine and nutritional value of OFSP through sensitization on the field demonstration and nutritional values