HARARE, Zimbabwe – The maize lethal necrosis (MLN) quarantine facility in southern Africa was officially opened in Zimbabwe on April 20, 2017 to enable safe introduction and exchange of novel maize germplasm from CIMMYT to partners in southern Africa.

Set up by the International Maize and Wheat Improvement Center (CIMMYT), with the approval of the government of Zimbabwe, the work for establishing the facility at the Plant Quarantine Station at Mazowe, outside Zimbabwe’s capital Harare, was initiated in the last quarter of 2015.  The five hectare MLN quarantine facility funded by the United States Agency for International Development, is the first of its kind in southern Africa and will be used to safely import elite maize breeding materials from CIMMYT to southern Africa.

MLN is a devastating disease that causes huge economic losses if it occurs, particularly for smallholder farmers who frequently do not have means to control it. MLN was first detected in Kenya in 2011, and has since been reported in Democratic Republic of the Congo, Ethiopia, Rwanda, Tanzania, and Uganda. It is caused by a double infection of maize plants by two viruses: the maize chlorotic mottle virus and the sugarcane mosaic virus. Severe infestation can result in total yield loss. MLN-causing viruses are transmitted not only by insect vectors, but also by seed. There is an urgent need to prevent the deadly disease from moving further south.

The MLN quarantine facility is now functional. To date, over two hectares of land have been planted successfully with maize breeding materials imported from Kenya for the purpose of proactively breeding for MLN while at the same time preventing movement of the disease from endemic areas. Personnel have been trained to safely conduct activities at the site. The facility operates under strict quarantine regulations and is closely monitored and approved by Zimbabwe’s Plant Quarantine Services to ensure that the maize materials introduced are MLN-free.

“This modern quarantine facility is expected to uphold safety when importing maize breeding materials to southern Africa, and to facilitate local and regional institutions to proactively breed for resistance against the MLN disease,” said Zimbabwe’s Minister for Agriculture, Mechanization and Irrigation Development, Joseph Made, while officially opening the facility.

Dr Made also said “I am confident that the quarantine facility will play a significant role in curbing the spread of MLN, while at the same time facilitating on-going work of developing new maize varieties that are resistant to the disease.”

“This MLN quarantine facility, and the collaborative efforts between institutions of the government of Zimbabwe, especially the Department of Research and Specialist Services (DR&SS) and CIMMYT-Southern Africa Regional Office, are key to prevent the possible spread of MLN in southern Africa, and to develop and deploy elite maize varieties with MLN resistance and other farmer-preferred traits,” said B.M. Prasanna, Director of the CIMMYT Global Maize Program and CGIAR Research Program MAIZE, while speaking at the same occasion.

CIMMYT and the government of Zimbabwe have so far conducted two nation-wide MLN surveys. In the first, no incidence of MLN was recorded. Results of the second survey are still being assessed. To strengthen the phytosanitary work at this MLN quarantine facility, CIMMYT will also offer capacity building to DR&SS researchers through trainings, technical assistance, and advisory services.

MLN is a reality that cannot be ignored. Partners have to work together to control its spread through finding practical solutions to tackle this complex challenge, including strengthening MLN disease diagnostic and surveillance capacity. In addition, intensive inter-institutional efforts to develop and deploy improved maize varieties that incorporate MLN resistance should be continued. The commercial seed sector must also play a key role by producing and delivering MLN-free healthy seed to farmers.

Until seed companies in the MLN-endemic countries have produced 100 percent MLN-free, clean commercial seed, and have necessary certification from the national plant protection offices, the potential risk of MLN entering southern Africa and the consequent damage to maize producers from significantly outweighs the benefits of commercial seed trade.

MLN can only be effectively prevented and tackled through concerted inter-institutional and multi-disciplinary action. The key actions include: enforcement of synchronized maize plantings and a maize-free period of at least three to four months in a year in severely affected areas; creation of an extension corps specifically dedicated to creating awareness on MLN management among the farming communities and monitoring and implementation of standard operating procedures for production of MLN-free clean seed at various points along the seed value chain, to be used by all players in the seed industry.

CIMMYT developed and released, through national partners in eastern Africa, nine MLN-tolerant maize hybrids in the last three years. Four among these hybrids are already being seed scaled-up and commercialized by seed company partners in Uganda, Kenya and Tanzania. As many as 19 MLN-tolerant hybrids are under national performance trials in eastern Africa.

EL BATAN, Mexico (CIMMYT) – A DuPont Pioneer leadership delegation visited CIMMYT HQ on May 12 to explore public-private collaboration approaches within the new CGIAR Excellence in Breeding Platform (EiB). The high level delegation, included Geoff Graham, Vice President of Plant Breeding, and other members of management from Global Breeding & Marker Technology Field Technology Innovation & Operations, and Africa, and Latin America regional operations. The team got acquainted with the EiB through interactions with CGIAR scientists and a tour of the CIMMYT scientific facilities.

The visit focused on mutually beneficial collaboration that would enable CGIAR and DuPont Pioneer breeding programs to better capitalize on each other’s experiences, and strengthen knowledge sharing in the pre-competitive domain. The ultimate aim is to improve public and private breeding programs targeting the developing world, including for crops with lower private sector investments.

This visit is the latest in a series of new public-private collaborations with DuPont Pioneer. During CIMMYT’s 50th anniversary celebrations DuPont Pioneer and CIMMYT entered a Master Alliance Agreement to jointly develop improved crops using CRISPR-Cas advanced plant breeding technology for characteristics that address the needs of smallholder farmers around the world.

“Public and private sector breeding programs may target different farming communities and agricultural commodities,” said Marianne Banziger, CIMMYT Deputy Director General for Research and Partnerships. “Nonetheless there are many areas where we can learn from each other and thereby accelerate benefits reaching farming communities, both in poorer and wealthier countries.”

The Excellence in Breeding Platform is one of three new platforms within the new CGIAR portfolio. Drawing from innovations in the public and private sector, the Platform will provide access to cutting-edge tools, services and best practices, application-oriented training and practical advice with the intention to modernize breeding programs targeting the developing world.

KATHMANDU, Nepal (CIMMYT) – Four Nepalese seed companies are showing signs of significant growth, with seed sales increasing nearly 60 percent since 2014.

About 70 percent of Nepal’s population is employed in the agriculture and forestry sector, accounting for 34 percent of the country’s gross national product. While farmers still face many challenges in accessing new technology, market opportunities and other inputs, Nepal’s seed industry is beginning to grow thanks to new investments in seed company operations and facilities. There are currently 20 locally registered seed companies that provide about 50 % of the nation’s formal seed supply system.

The four  companies – New Shreeram, Lumbini Seed Company, GATE Nepal Pvt. Ltd. and Unique – are part of a group of 10 Nepalese companies that have worked with the International Maize and Wheat Improvement Center (CIMMYT) through the Cereal Systems Initiative for South Asia (CSISA) since 2014 to improve their marketing and sales strategies, business development, product range and quality.

This growth is notable in Nepal’s emerging cereal seed industry, which is composed primarily of small- to medium-scale enterprises that often lack business plans, have relatively low operating capital and have limited processing and storage facilities. These companies produce open-pollinated crop varieties, which are then released and registered by Nepal’s National Seed Board.

Half of the companies working with CIMMYT have so far been able to secure financial resources of up to $200,000 each from Nepal’s Ministry of Agricultural Development.

“These additional funds have allowed the seed companies to expand their facilities to include seed storage buildings, processing plants and laboratories,” said Upadhaya. “They have also included newly released iron- and zinc-rich varieties in their product lines.”

Some companies have also introduced innovative incentives for their producers by bearing the transportation costs of seed from the farmers’ fields to the company stores as a way to boost sales, according to Upadhaya.

The Seed Entrepreneurs’ Association of Nepal (SEAN) – the seed companies’ umbrella organization – has increased its membership from 600 in 2014 to 1,000 in 2016, formed three regional chapters and contributed a unified voice to discussions around agricultural policies of interest to the seed industry, said Laxmi Kanta Dhakal, SEAN Chairman.

As a result of these new technologies and investments, seed sold by these companies increased significantly and reached marginal areas of the country through new development networks and private sector traders.

New contractual agreements have since been signed between seed companies, informal groups and cooperatives for the production of seed. As outlined in Nepal’s Agricultural Development Strategy (2015-2025), these initiatives will help promote inclusive growth and an effective seed sector in Nepal.

CIMMYT launched the CSISA in 2009 to promote durable change at scale in South Asia’s cereal-based cropping systems. CIMMYT operates rural “innovation hubs” in Bangladesh, India and Nepal to increase the adoption of various resource-conserving and climate-resilient technologies, and to improve farmer access to market information and enterprise development. Learn more about CSISA’s impact here.

DHAKA, Bangladesh (CIMMYT) – A delegation of USAID representatives recently visited southern Bangladesh to learn about sustainable agriculture activities in the area and emerging challenges to wheat production.

Agriculture employs nearly two-thirds of Bangladesh’s population, with a majority of farmers owning land of less than half an acre, putting intense pressure on farmland while having to adapt to various environmental challenges from flooding and rising temperatures due to climate change, to increasing labor scarcity and production costs.

Despite these challenges, Bangladesh has successfully adopted sustainable technologies that conserve natural resources, improve productivity and increase profits, particularly with the two-wheeled tractor that is used by around 80 percent of farmers due to its versatility and ability to be fitted with a variety of additional equipment for planting, threshing and irrigation.

Challenges to widespread adoption of these innovations, however, remain a challenge.

“Much of this innovation has not reached farmers at scale because commercialization has been impeded by the lack of standardization,” according to Andrew McDonald, cropping systems agronomist at the International Maize and Wheat Improvement Center (CIMMYT) and project leader of the CIMMYT-led Cereal Systems Initiative for South Asia (CSISA). “Most workshops create a unique machine every time a new piece is fabricated, which drives up costs to both manufacture and repair the machinery. Quality control is also an issue.”

From March 16-19, the USAID delegation visited farmers and agricultural machinery service providers in the Barisal, Jessore and Jhenaidah districts of Bangladesh, seeing firsthand how CIMMYT is working with NGOs, public and private sector partners to ensure that machinery is scaled, available and affordable to the most marginalized farmers.

The delegation, comprising USAID Senior Program Analyst Charisse Adamson, Water and Irrigation Advisor Biniam Iyob and Food Security Advisor Christopher Chibwana, also learned about various sustainable technologies from axial flow pumps that irrigate crops at reduced cost, to two-wheeled tractors developed by Janata Engineering; a small-scale but rapidly growing agricultural machinery manufacturer, importer and dealer that has been working closely with CSISA over the past seven years.

The visitors also observed how farmers are growing healthy rice seedlings for higher yields in community based seedbeds. Farmer-friendly learning videos are jointly produced by the project with the Bangladesh Rice Research Institute and shown by the  Agricultural Advisory Society, with over 35,000 farmers learning about healthy rice seedlings between November 2016 and January this year.

The USAID team then visited the Bangladesh Agricultural Research Institute in Jessore to learn about wheat blast mitigation efforts in the region, which emerged in early 2016. The spread of wheat blast could be devastating to South Asia, which is home to 300 million undernourished people and whose inhabitants consume over 100 million tons of wheat each year.

“I have learned so much…I think you are doing a great job in making research outputs sustainable through strategic value chain pathways,” said Iyob at the end of the visit.

CIMMYT launched the CSISA in 2009 to promote durable change at scale in South Asia’s cereal-based cropping systems. CIMMYT operates rural “innovation hubs” in Bangladesh, India and Nepal to increase the adoption of various resource-conserving and climate-resilient technologies, and to improve farmer access to market information and enterprise development. Learn more about CSISA’s impact here.

EL BATAN, Mexico (CIMMYT) – Small-scale agricultural mechanization is showing signs it has the potential to fuel rural employment for youth in sub-Saharan Africa, according to researchers at the International Maize and Wheat Improvement Center (CIMMYT).

Across Africa, youth are struggling with high unemployment and working poverty, the International Labor Organization records. However, increased adoption of agricultural mechanization –  especially machines that are small, affordable and easy to maintain such as two-wheel tractors – is stimulating jobs and entrepreneurial opportunities for African youth, said Frédéric Baudron, senior systems agronomist at CIMMYT.

“Small-scale mechanization is more equitable than other forms of mechanization as even the poorest and most vulnerable have access to it,” he said.

Youth, along with women, are typically subject to labor intensive farm activities causing them to shun agriculture. But with mechanization improving productivity while reducing drudgery, youth are seeing economic opportunity in agribusiness, on rural farms and as service providers, said Rabe Yahaya, a CIM/GIZ integrated expert specialized in mechanization for sustainable agriculture intensification.

As a result, new jobs along the value chain from mechanics to spare parts providers have been created, he added.

Relatively cheap and easy to operate two-wheel tractors can be used for many different applications. On-farm, the tractors are used to speed up crop establishment while conserving soils through reduced tillage and precision fertilizer application. They allow farmers to tap into surface water for irrigation as well as aid shelling grain to reduce the time taken to get to market. The machinery has also been used to start rural commercial hire and transport services.

24-year-old Beyene Abebe from Ethiopia is one youth benefiting from mechanization. Through CIMMYT managed training, Abebe has developed the skills needed to become a mechanization service provider. He now provides transportation services for an average of 200 households annually and ploughing services for 40 farmers in his village using two-wheel tractors. With the income from his service, Abebe can cover his family’s expenses and he bought farmland with his savings.

National government support for training and innovation is key to bolster agricultural mechanization throughout Africa, said Baudron. By creating a conductive business environment to attract private sector actors, governments can grease the wheels to scale out success.

Both Yahaya and Baudron shared some insights on the opportunities agricultural mechanization can provide rural communities in the following interview.

Q: Why is it important that agricultural research for development targets youth in rural areas?

RY: A growing population and diet change is increasing food demand in Africa, however, the amount of arable land is decreasing. This affects rural areas, where agriculture remains the main source of income and livelihood. Agriculture in the way it is currently practiced in rural areas is no longer attractive to the new generation of youth as it is labor intensive, rudimentary, risky, unproductive and does not support a good livelihood.

In addition, only 2 percent of Africa’s youth are undertaking agricultural curriculum at the university level. Despite young Africans being more literate than their parents, they suffer from increased unemployment. Agriculture could be the solution in tackling youth unemployment in rural areas, therefore providing peace, stability and food security.

FB: Youth unemployment is growing. Agriculture is perceived as a sector that can absorb much of this unemployment, particularly when combined with entrepreneurship.

In my view, an important issue when tackling issues of sustainable development as opposed to simply ‘development,’ is the issue of equity. We must ensure that the largest amount of people benefit from our interventions. Rural youth represent a large proportion of the vulnerable households in the areas where we work, because they lack capital and other resources, similar to women-headed households.

Q: How is mechanization creating new rural opportunities for youth and women?

RY: In many societies, youth and women are unequally disadvantaged and perform the most labor intensive agricultural activities such as plowing, sowing, weeding, harvesting, shelling, water pumping, threshing and transportation with very rudimentary implements using human and animal power. Therefore, increasing the use of engine power in agriculture will free youth and women from production drudgery discrepancies and most importantly increase farm productivity and consequently improve income generation if an organized value chain exists with a strong private sector involvement.

FB: Mechanization creates rural employment. It creates work for service provider jobs and it also stimulates other businesses along the mechanization value chains. Once demand for mechanization is established, employment opportunities grow for mechanics, fuel providers, savings and loans associations, spare part dealers, etc.

Q: What lessons are there to aid youth to be successful mechanization service providers?

RY: Training in mechanical, agronomic and business skills. Again training and constant follow up is key in order not only to produce successful youth mechanization service provider, but to ensure their continued success. In addition, infrastructure, aftersales — service and spare parts dealerships and financial schemes, promote the adoption of mechanization and support the development of value chain markets are crucial to success.

And remember whatever the technology may be, the farmer has to be able to earn money from it, otherwise they will not use it!

FB: Youth also tend to be better at managing modern technologies. We found consistently, in all countries where we work, that being a successful service provider is highly correlated to be a member of the youth. However, other factors are also important such as being entrepreneurial, educated, able to contribute to the cost of the machinery, and preferably having an experience in similar businesses and particularly in mechanics

Working with CIMMYT’s Farm Mechanization and Conservation Agriculture for Sustainable Intensification (FACASI) project, researchers have sought to promote the delivery and adoption of small-scale machines to make farming practices – including planting, harvesting, water pumping, shelling and transporting – more productive and sustainable in eastern and southern Africa. Funded by the Australian Center for International Agricultural Research, FACASI offers support throughout the supply chain, from importers to manufacturers, service providers and extension workers to ensure mechanization reaches farmers.

CIMMYT’s mechanization team has ongoing collaboration with GIZ/BMZ green innovation center in Ethiopia and works in Namibia with GIZ to provide knowledge, expertise and capacity building on conservation agriculture.

Further information:

Rural21 features CIMMYT mechanization experts

Mechanization for smallholder farmers fact sheet

EL BATAN, Mexico (CIMMYT) – A comprehensive study of genetic gains resulting from long term breeding work on improved hybrids and open-pollinated varieties (OPVs) in eastern and southern Africa shows that with appropriate funding, maize yields can continue to increase in extreme heat and drought conditions.

Investments into maize breeding and seed systems must expand to keep up with the capacity to withstand climate variability in the region, said Jill Cairns, one of the authors of the study, emphasizing that maize breeding is on track to meet the challenges of climate change in Africa.

The region is currently experiencing large climate variability, including the 2014-2015 drought; the 2015-2016 El Nino and severe drought and flooding in 2016-2017.

“We see evidence that increased investment works,” said Cairns, a maize physiologist with the International Maize and Wheat Improvement Center (CIMMYT) in Zimbabwe. “Although our breeding work has led to higher genetic gains, yields remain lower, reflecting smaller research investments over time. On the other hand, in countries like the United States and China, which have become the top two maize producers worldwide, we see the beneficial impact of steady investments.”

Varieties released by CIMMYT’s partners in sub-Saharan Africa between the years 2000 and 2010, showed that genetic gains for yields made through this improved maize germplasm compare favorably with similar studies in other regions in better growing conditions — in China and the United States, for example.

On average, under optimal conditions, CIMMYT maize breeders increased yields by 109 kilograms per hectare per year, under managed drought conditions, 33 kilograms per hectare per year and under random drought conditions, 23 kilograms per hectare per year. By comparison, in China, under optimal conditions, gains were estimated at 95 kilograms per hectare per year and in the United States, 65 to 75 kilograms per hectare per year.

“Breeding is a long term investment but it ultimately pays off through improved varieties for smallholder farmers,” said Jill Cairns, a maize physiologist with CIMMYT in Zimbabwe, describing the impact of the breeding program in sub-Saharan Africa, which has been underway for more than 30 years.

“We’re constantly changing the breeding pipeline to ensure that the genetic gains are continuously increased,” she added. “Gains are illustrated by sustained increases in grain yield over time. In fact, we expect to see a higher genetic gain through the more recent hybrids developed by CIMMYT maize breeding team than those reported in the study undertaken on hybrids released between 2000 and 2010 because we’ve added a lot of new tools and we are incorporating many new technologies to further increase gains.”

The study confirmed that the lowest genetic gains occurred under low nitrogen conditions where little fertilizer was used, Cairns said, emphasizing the importance of increasing the potential for genetic gains to boost grain yields in areas with poor soil fertility throughout the region.

Scientists working with the CIMMYT maize breeding program primarily focus on developing hybrids, which result from the deliberate crossing of genetically diverse inbred lines that exhibit a wide variety of traits that are relevant for smallholders in the tropics.

Improved OPVs were developed at CIMMYT, using selected sets of inbred lines to reflect traits of the parental lines.  In general, genetic gains in the OPVs released during the period under review were found to be higher than for the hybrids, although grain yields in the hybrids were certainly higher.

Resource-poor farmers in some African countries tend to use drought-tolerant improved OPVs, especially where the maize seed sector is weak or improved hybrid seeds are unavailable or unaffordable.

“Accessing hybrid seeds can be a real challenge for resource-poor, smallholder farmers in some areas,” Cairns said. “Hybrids also pose a conundrum for farmers in extremely drought-prone areas, where the tendency is to minimize the risk by using low-cost improved OPVs rather than investing in relatively higher-cost hybrid seeds.”

Yield gain in the CIMMYT-derived hybrids in eastern and southern Africa during the study period is comparable with gains reported in the United States and China. However, absolute yields in the region are still lower, reflecting the opportunity to further improve the yield potential of tropical maize, including in stress-prone environments.

Additionally, maize yields in sub-Saharan Africa, where maize accounts for 50 percent of cereal production in over 50 percent of countries, are still the lowest in the world.  National maize yields in 30 countries in the region remain much lower than yields were in the U.S. Corn Belt in 1926 before hybrids were introduced!

Since the CIMMYT breeding program started in Zimbabwe in 1985 (part of the southern Africa region where maize accounts for 45 percent of calories and 43 percent of protein from cereals consumed), scientists have focused on increasing drought tolerance, among other important traits. Currently, the Stress Tolerant Maize for Africa (STMA) project operates in 11 countries across sub-Saharan Africa.

Continual evaluation is a critical component of crop improvement, according to scientists.

“Quantifying genetic gain each year is an integral part of our product development process,” said B.M. Prasanna, director of CIMMYT’s Global Maize Program, and the CGIAR Research Program MAIZE. “This enables us to measure the progress being made, and to make necessary adjustments for continuous improvement of the performance of our products in the target agro-ecologies we serve.”

The research benefits are far-reaching.

In these two first-ever reviews evaluating genetic gains through CIMMYT’s maize breeding program in eastern and southern Africa, we get a clear understanding of benefits and impact of improved maize hybrids and OPVs released during 2000 to 2010, said Marianne Bänziger, who previously led the CIMMYT maize program, and is now deputy director general of research and partnerships at the organization.

“Use of improved seed has been increasing in sub-Saharan Africa and greater uptake is mostly a question of where the seed sector reaches,” Bänziger said. “The issue of variety replacement is complex. Working with governments and seed companies is a key part of our role.”

The dissemination and adoption of drought tolerant maize could generate as much as $590 million for farmers over a seven-year period, Cairns said. “As we take stock of the important role our work has played in this impoverished and environmentally harsh region, we’re grateful for the vital funding we receive from various agencies, especially the Bill & Melinda Gates Foundation, the U.S. Agency for International Development, and the CGIAR research program MAIZE.”

Read the research papers:

Gains in Maize Genetic Improvement in Eastern and Southern Africa: 1. CIMMYT Hybrid Breeding Pipeline

Gains in Maize Genetic Improvement in Eastern and Southern Africa: II. CIMMYT Open-Pollinated Variety Breeding Pipeline

MEXICO CITY (CIMMYT) – CIMMYT doctoral student and ETH Zürich graduate Stephanie Cheesman has won the 2017 Hans Vontobel-Preis.

This ETH prize awards 5,000 Swiss Francs ($4,988) annually to the student with the most outstanding thesis in Agricultural Science. The prize is financed by a private fund set up in 1994 by the late banking doyen Hans Vontobel.

Cheesman conducted her thesis project “Finding the truth in wishful thinking: an on-farm study on maize-based conservation agriculture systems in Southern Africa” while working with CIMMYT in Zimbabwe on a post financed by the Swiss Development Cooperation (SDC).

The thesis investigated the effects of conservation agriculture (CA) on maize yields and soil carbon stocks, as well as other plant nutrient stocks in the soil. It is based on data collected on 125 on-farm research sites CIMMYT had established between 2004 and 2009 in Malawi, Mozambique, Zambia and Zimbabwe.

The results showed that yields could quickly increase with CA, whereas soil carbon stocks showed – after up to only seven years of CA practice – limited response under the prevailing conditions of Zimbabwe. Farmers also generally adapt CA systems to their conditions rather than adopt the system, due to the fact that there are many more factors besides improved yields – such as preferences in crops grown, availability of inputs and access to other sources of income – that influence why a farmer adopts a technique.

The award panel consisted of Maja Baumann, granddaughter of Vontobel, Bruno Studer, professor and chair of the molecular plant breeding group at ETH Zürich and Sarah Springman, professor and rector of ETH Zürich.

Baumann cited Cheesman’s valuable hard data about conservation agriculture – a topic that has been strongly debated in recent years – and contribution to sustainable agriculture as main reasons for her selection. Further the jury appreciated that the thesis investigated both biophysical and socio-economic aspects, allowing for a better understanding of conservation agriculture’s impact.

Cheesman completed her thesis under the supervision of Emmanuel Frossard, professor at ETH Zürich, CIMMYT Senior Cropping Systems Agronomist Christian Thierfelder and Neal Eash, professor at the University of Tennessee. Professor Johan Six from ETH Zürich evaluated the work as external examiner.

“Stephanie Cheesman’s collaborative project between CIMMYT and the Swiss institutions funded by SDC highlights the strong interest of all organizations to extend sustainable agriculture intensification, with the aim of increasing food and nutrition security and eradicate poverty amongst smallholder farmers in southern Africa,” said Thierfelder.

Cheesman’s thesis is available online through ETH-Zürich’s library here.