While previous studies have demonstrated the importance of organic material in soil for sustainable agricultural practices, there has been limited research into how organic material application affects the soil microbial community structures.
Dried young maize plants were added to the soil in the laboratory. After three days of incubation, soil samples were analyzed using shotgun metagenomic sequencing to discover how the application of young maize plants affects the structure of microbial communities in arable soil, how the potential functioning of microbial communities is altered, and how the application affects the soil taxonomic and functional diversity.
Bacterial and viral groups were strongly affected by organic material application, whereas archaeal, protist and fungal groups were less affected. Soil viral structure and richness were impacted, as well as metabolic functionality. Further differences were recorded in cellulose degraders with copiotrophic lifestyle, which were enriched by the application of young maize plants, while groups with slow growing oligotrophic and chemolithoautotrophic metabolism performed better in unamended soil.
Given the importance of embedding and adopting sustainable agricultural practices as part of climate change adaptation and mitigation, the study improves our insight in a key aspect of sustainable agriculture, the management of crop residues.
A recently published study in Nature Communications Biology journal demonstrates the potential of a novel seed production technology to transform Africa’s seed production system, conferring important benefits to smallholder maize farmers and seed companies in sub-Saharan Africa.
The Seed Production Technology for Africa (SPTA) process enables production of non-pollen-producing inbred seed that can be used in a two-step multiplication process to produce commercial seed of hybrid varieties containing equal parts pollen producing and non-pollen producing plants. The pollen producing plants provide pollen for the entire field, while the non-pollen producing plants deliver additional grain since they save energy by not producing pollen. Hybrids in which fifty percent of the plants are non-pollen producing have a significant grain yield advantage compared with hybrids in which all plants produce pollen.
Farmers and researchers evaluated the performance of fifty percent non-pollen producing (FNP) hybrids in side-by-side comparisons across diverse farm sites in Kenya, South Africa, and Zimbabwe between 2016 and 2019. The results demonstrate that FNP hybrids deliver an average yield increase of 200 kg per hectare, representing a 10-20% increase at current sub-Saharan Africa yield levels where farmers face frequent drought and sub-optimal soil fertility. The FNP yield advantage was consistent in both low yielding and higher yielding conditions. Additionally, in extensive farmer surveys, farmers rated the FNP hybrids higher than the pollen producing counterparts, recognizing the grain yield advantage. Favorable rating of FNP hybrids suggests that farmers are likely to adopt them once available.
Although consistent and steady improvement is being made for grain yield potential through plant breeding, the yield benefit of FNP hybrids is the equivalent of approximately six years of breeding progress under stressful conditions. The FNP trait provided a consistent yield advantage in several genetically unique hybrids evaluated, indicating that the yield advantage from FNP will be complementary to and additive with progress from maize breeding efforts.
In sub-Saharan Africa, the challenge of delivering genetically pure, high-quality seed is substantial. Seed companies in the region contend with a complex and costly system to produce commercial seed. In addition to delivering higher grain yield to farmers through the FNP trait, the SPTA process will reduce the complexity of seed production, enabling seed producers to deliver higher purity improved hybrid seeds in sufficient quantities for smallholder farmers.
Hybrid seed production requires that one of the parents of the hybrid is prevented from producing pollen, ensuring that the seed harvested has been cross-fertilized by the pollen parent. Most hybrid seed production in sub-Saharan Africa involves physical removal of the tassels of the seed parent prior to the release of pollen, a process known as detasseling. Detasseling is important in commercial seed production to prevent self-fertilization of the seed parent plants. Nearly all detasseling in sub-Saharan Africa is done by hand, which is a labor-intensive and time-sensitive process. Poorly executed or ill-timed detasseling results in unwanted self-fertilization of the seed parent, leading to rejection of seed and incurring losses to the seed producer. Furthermore, timely detasseling typically involves removal of one or more leaves together with the tassel, reducing the photosynthetic capacity of the plant, and lowering the seed yield.
Use of the SPTA process ensures that the seed parent of the hybrid will not produce pollen, thereby eliminating the need for detasseling. This means seed producers can ensure higher integrity of hybrid seed while reducing costs and increasing seed yield. The technology is well suited for the three-way hybrid production commonly used in sub-Saharan Africa. Economic advantages to seed companies of using seed from the SPTA process is also expected to provide incentive to replace older, lower yielding varieties with more recently developed hybrids. Providing improved quality seed of better hybrids while delivering the yield advantage of the FNP trait can benefit smallholder maize farmers throughout the region. Saving costs can help the seed sector remain strong and competitive, which leads to increasingly better options for farmers in the future.
The research was conducted by scientists from the Seed Production Technology for Africa project, a collaborative initiative of the Agricultural Research Council of South Africa (ARC), International Maize and Wheat Improvement Center (CIMMYT), CortevaTM Agriscience, Kenya Agricultural and Livestock Research Organization (KALRO), and QualiBasic Seed Company (QBS).
Cover photo: A woman with a baby on her back evaluating maize plants farmer’s plots hosting FNP trials in Embu, Kenya. Photo: Hugo DeGroote/CIMMYT
Analysis of evidence by scientists of the International Maize and Wheat Improvement Center (CIMMYT) and CGIAR concludes that the scientific risks of genome editing are similar to those of traditional breeding: all new varieties, however developed, need to be tested for agronomic performance in a range of environments.
Social risks are mainly that these powerful technologies may be rendered inaccessible to less-commercial crops and farmers if intellectual property (IP) and regulatory policies make them expensive or difficult to use.
Genome editing has demonstrated potential to contribute to food security, improved nutrition, and value addition for farmers and consumers.
Many countries are still uncertain about whether to grow, or if and how to regulate genome-edited crop varieties. The Court of Justice of the European Union (CJEU) has stated that genome-edited crops should be considered as transgenics in the EU for regulatory purposes, a decision that could limit their use in Africa. On the other hand, several countries, including USA, Canada, Brazil, Colombia, Argentina, Chile, Kenya, Nigeria, Israel, India, and Japan have determined that genome-edited crops should not be regulated like transgenics if they do not contain foreign DNA.
Policies should enable choice and avoid the risk that genome editing technologies for crops benefit only those who can pay premium price. Smallholder farmers should have equal access to advanced technologies, should they wish to use them, as well as relevant and objective information about their value and how to use them.
Cereals cover around 80% of Nepal’s cultivated land area, with a low level of productivity. The country’s commercial cereal seed sector development has been rather slow as more than 83% of seed comes from the informal system. The formal sector cannot produce adequate seeds to meet the farmers’ needs. Moreover, the formal market is largely driven by public seed varieties. To catalyze the sector’s development and enhance productivity, building a well-performing seed system that produces and timely supplies quality seeds at affordable rates to farmers is integral.
The adoption of a federal system of governance since 2018, creating new structures within the system, along with the after-effects of COVID-19 has impacted the public sector seed production and distribution with implications on private seed business. A recent assessment conducted by the International Maize and Wheat Improvement Center (CIMMYT) examines the current functions in the cereal value chain in Nepal and identifies upgrading strategies to bring efficiency and competitiveness in the cereal seed market systems, specifically for rice and maize.
An agrovet owner sells improved varieties of maize and rice locally produced by GATE Nepal Seed Company, a partner of CIMMYT in Banke, Nepal (Photo: Bandana Pradhan/CIMMYT)
The study provides a detailed analysis of the market size and trends for the various hybrid and open-pollinated varieties of rice and maize seeds as well as their production, distribution and margins in seed business.
A majority of rice and maize seeds, especially high-yielding hybrids, sold to farmers are brought in by importers and wholesalers who directly sells them to farmers or indirectly through agro-dealers. Nepali hybrid varieties are lagging because farmers, grain producers and millers have low awareness and information on new and improved varieties produced by local seed companies and cooperatives. A significant supply gap of rice and maize seeds was found in all the seven provinces of Nepal.
The study reviews the nature of inter-business relations in the seed value chain and provision of services by the government, NGOs and others for the development of the cereal seed value chain. In the context of federalism, the study assesses the seed policies and actions under the Revised Seed Act (2020) to establish provincial seed systems. Considering migration-induced feminization of agriculture in Nepal, the study identifies approaches to promote inclusive seed systems and youth engagement in seed value chains. Strategic measures to build a resilient seed system that can respond to abrupt market and mobility disruptions, as caused by the COVID-19 pandemic, is also taken into account. However, it also details out the various challenges and risks encountered by the value chain actors that hinders seed business and the sector’s growth overall.
CIMMYT designed seed packets of maize and rice to enhance branding and marketing of local products displayed in an agrovet in Banke district, Nepal (Photo: Bandana Pradhan/CIMMYT)
Some of the strategies to address these bottlenecks include strengthening value chain functions in research and development, hybrid seed production, seed processing and innovative approaches for market promotion and sales. Creating an enabling environment for seed companies in areas of variety testing and release, quality assurance in seed production and commercialization, financial and business management services, seed extension services and promotion of new domestic varieties are also fundamental propositions to achieve Nepal’s National Seed Vision (2013-2025) targets.
This open-access textbook provides a comprehensive, up-to-date guide for students and practitioners wishing to access the key disciplines and principles of wheat breeding. Edited by Matthew Paul Reynolds, head of Wheat Physiology at CIMMYT, and Hans-Joachim Braun, former Director of CIMMYT’s Global Wheat Program, it covers all aspects of wheat improvement, from utilizing genetic resources to breeding and selection methods, data analysis, biotic and abiotic stress tolerance, yield potential, genomics, quality nutrition and processing, physiological pre-breeding, and seed production.
It will give readers a balanced perspective on proven breeding methods and emerging technologies. The content is rich in didactic material that considers the background to wheat improvement, current mainstream breeding approaches, translational research, and avant-garde technologies that enable breakthroughs in science to impact productivity, facilitating learning.
While the volume provides an overview for professionals interested in wheat, many of the ideas and methods presented are equally relevant to small grain cereals and crop improvement in general.
All chapter authors are world-class researchers and breeders whose expertise spans cutting-edge academic science to impacts in farmers’ fields.
Given the challenges currently faced by academia, industry, and national wheat programs to produce higher crop yields, often with fewer inputs and under increasingly harsher climates, this volume is a timely addition to their toolkit.
For the first time ever, a biotechnology team has identified vegetative storage proteins (VSP) in maize and activated them in the leaves to stockpile nitrogen reserves for release when plants are hit by drought, which also causes nutrient stress, according to a recent report in Plant Biotechnology Journal. In two years of field testing, the maize hybrids overexpressing the VSP in leaf cells significantly out-yielded the control siblings under managed drought stress applied at the flowering time, according to Kanwarpal Dhugga, a principal scientist at the International Maize and Wheat Improvement Center (CIMMYT).
“One of the two most widely grown crops, maize increasingly suffers from erratic rainfall and scarcer groundwater for irrigation,” Dhugga said. “Under water stress, nitrogen availability to the plant is also attenuated. If excess nitrogen could be stored in the leaves during normal plant growth, it could help expedite the plant’s recovery from unpredictable drought episodes. In our experimental maize hybrids, this particular VSP accumulated to more than 4% in mesophyll cells, which is five times its normal levels, and offered an additional, dispensable source of nitrogen that buffered plants against water deficit stress.”
Dhugga noted as well that the study, whose authors include scientists from Corteva Agriscience, the Bill & Melinda Gates Foundation, and the US Department of Agriculture (USDA), provides experimental evidence for the link between drought tolerance and adequate nitrogen fertilization of crop plants. “This mechanism could also help farmers and consumers in sub-Saharan Africa, where maize is grown on nearly 40 million hectares, accounts for almost one-third of the region’s caloric intake, and frequently faces moderate to severe drought.”
Scientists multiply and power up vegetative storage proteins in maize leaves as nutrient stockpiles for drought-stressed maize crops. Graphic adapted from: Pooja Gupta, Society for Experimental Biology (SEB).
A climate change hotspot region that features both small-scale and intensive farming, South Asia epitomizes the crushing pressure on land and water resources from global agriculture to feed a populous, warming world. Continuous irrigated rice and wheat cropping across northern India, for example, is depleting and degrading soils, draining a major aquifer, and producing a steady draft of greenhouse gases.
Through decades-long Asian and global partnerships, the International Maize and Wheat Improvement Center (CIMMYT) has helped to study and promote resource-conserving, climate-smart solutions for South Asian agriculture. Innovations include more precise and efficient use of water and fertilizer, as well as conservation agriculture, which blends reduced or zero-tillage, use of crop residues or mulches as soil covers, and more diverse intercrops and rotations. Partners are recently exploring regenerative agriculture approaches — a suite of integrated farming and grazing practices to rebuild the organic matter and biodiversity of soils.
Along with their environmental benefits, these practices can significantly reduce farm expenses and maintain or boost crop yields. Their widespread adoption depends in part on enlightened policies and dedicated promotion and testing that directly involves farmers. We highlight below promising findings and policy directions from a collection of recent scientific studies by CIMMYT and partners.
Getting down in the dirt
A recent scientific review examines the potential of a suite of improved practices — reduced or zero-tillage with residue management, use of organic manure, the balanced and integrated application of plant nutrients, land levelling, and precise water and pest control — to capture and hold carbon in soils on smallholder farms in South Asia. Results show a potential 36% increase in organic carbon in upper soil layers, amounting to some 18 tons of carbon per hectare of land and, across crops and environments, potentially cutting methane emissions by 12%. Policies and programs are needed to encourage farmers to adopt such practices.
Another study on soil quality in India’s extensive breadbasket region found that conservation agriculture practices raised per-hectare wheat yields by nearly half a ton and soil quality indexes nearly a third, over those for conventional practices, as well as reducing greenhouse gas emissions by more than 60%.
Ten years of research in the Indo-Gangetic Plains involving rice-wheat-mungbean or maize-wheat-mungbean rotations with flooded versus subsoil drip irrigation showed an absence of earthworms — major contributors to soil health — in soils under farmers’ typical practices. However, large earthworm populations were present and active under climate-smart practices, leading to improved soil carbon sequestration, soil quality, and the availability of nutrients for plants.
The field of farmer Ram Shubagh Chaudhary, Pokhar Binda village, Maharajganj district, Uttar Pradesh, India, who has been testing zero tillage to sow wheat directly into the unplowed paddies and leaving crop residues, after rice harvest. Chaudhary is one of many farmer-partners in the Cereal Systems Initiative for South Asia (CSISA), led by CIMMYT. (Photo: P. Kosina/CIMMYT)
Rebooting marginal farms by design
Using the FarmDESIGN model to assess the realities of small-scale, marginal farmers in northwestern India (about 67% of the population) and redesign their current practices to boost farm profits, soil organic matter, and nutritional yields while reducing pesticide use, an international team of agricultural scientists demonstrated that integrating innovative cropping systems could help to improve farm performance and household livelihoods.
More than 19 gigatons of groundwater is extracted each year in northern India, much of this to flood the region’s puddled, transplanted rice crops. A recent experiment calibrated and validated the HYDRUS-2D model to simulate water dynamics for puddled rice and for rice sown in non-flooded soil using zero-tillage and watered with sub-surface drip irrigation. It was found that the yield of rice grown using the conservation agriculture practices and sub-surface drip irrigation was comparable to that of puddled, transplanted rice but required only half the irrigation water. Sub-surface drip irrigation also curtailed water losses from evapotranspiration and deep drainage, meaning this innovation coupled with conservation agriculture offers an ecologically viable alternative for sustainable rice production.
Given that yield gains through use of conservation agriculture in northern India are widespread but generally low, a nine-year study of rice-wheat cropping in the eastern Indo-Gangetic Plains applying the Environmental Policy Climate (EPIC) model, in this case combining data from long-term experiments with regionally gridded crop modeling, documented the need to tailor conservation agriculture flexibly to local circumstances, while building farmers’ capacity to test and adapt suitable conservation agriculture practices. The study found that rice-wheat productivity could increase as much as 38% under conservation agriculture, with optimal management.
Key partner organizations in this research include the following: Indian Council of Agricultural Research (ICAR); Central Soil Salinity Research Institute (CSSRI), Indian Agricultural Research Institute (IARI), Indian Institute of Farming Systems Research (IIFSR), Agriculture University, Kota; CCS Haryana Agricultural University, Hisar; Punjab Agricultural University, Ludhiana; Sri Karan Narendra Agriculture University, Jobner, Rajasthan; the Borlaug Institute for South Asia (BISA); the Trust for Advancement of Agricultural Sciences, Cornell University; Damanhour University, Damanhour, Egypt; UM6P, Ben Guerir, Morocco; the University of Aberdeen; the University of California, Davis; Wageningen University & Research; and IFDC.
Generous funding for the work cited comes from the Bill & Melinda Gates Foundation, The CGIAR Research Programs on Wheat Agri-Food Systems (WHEAT) and Climate Change, Agriculture and Food Security (CCAFS), supported by CGIAR Fund Donors and through bilateral funding agreements), The Indian Council of Agricultural Research (ICAR), and USAID.
Cover photo: A shortage of farm workers is driving the serious consideration by farmers and policymakers to replace traditional, labor-intensive puddled rice cropping (shown here), which leads to sizable methane emissions and profligate use of irrigation water, with the practice of growing rice in non-flooded soils, using conservation agriculture and drip irrigation practices. (Photo: P. Wall/CIMMYT)
Spot blotch, a major biotic stress challenging bread wheat production is caused by the fungus Bipolaris sorokiniana. In a new study, scientists from the International Maize and Wheat Improvement Center (CIMMYT) evaluate genomic and index-based selection to select for spot blotch resistance quickly and accurately in wheat lines. The former approach facilitates selecting for spot blotch resistance, and the latter for spot blotch resistance, heading and plant height.
Genomic selection
The authors leveraged genotyping data and extensive spot blotch phenotyping data from Mexico and collaborating partners in Bangladesh and India to evaluate genomic selection, which is a promising genomic breeding strategy for spot blotch resistance. Using genomic selection for selecting lines that have not been phenotyped can reduce the breeding cycle time and cost, increase the selection intensity, and subsequently increase the rate of genetic gain.
Two scenarios were tested for predicting spot blotch: fixed effects model (less than 100 molecular markers associated with spot blotch) and genomic prediction (over 7,000 markers across the wheat genome). The clear winner was genomic prediction which was on average 177.6% more accurate than the fixed effects model, as spot blotch resistance in advanced CIMMYT wheat breeding lines is controlled by many genes of small effects.
“This finding applies to other spot blotch resistant loci too, as very few of them have shown big effects, and the advantage of genomic prediction over the fixed effects model is tremendous”, confirmed Xinyao He, Wheat Pathologist and Geneticist at CIMMYT.
The authors have also evaluated genomic prediction in different populations, including breeding lines and sister lines that share one or two parents.
Spot blotch susceptible wheat lines (left) and resistant lines. (Photo: Xinyao He and Pawan Singh/CIMMYT)
Index selection
One of the key problems faced by wheat breeders in selecting for spot blotch resistance is identifying lines that are genetically resistant to spot blotch versus those that escape and exhibit less disease by being late and tall. “The latter, unfortunately, is often the case in South Asia”, explained Pawan Singh, Head of Wheat Pathology at CIMMYT.
A potential solution to this problem is the use of selection indices that can make it easier for breeders to select individuals based on their ranking or predicted net genetic merit for multiple traits. Hence, this study reports the first successful evaluation of the linear phenotypic selection index and Eigen selection index method to simultaneously select for spot blotch resistance using the phenotype and genomic-estimated breeding values, heading and height.
This study demonstrates the prospects of integrating genomic selection and index-based selection with field based phenotypic selection for resistance in spot blotch in breeding programs.
Spot blotch, caused by the fungus Biopolaris sorokiniana poses a serious threat to bread wheat production in warm and humid wheat-growing regions globally, affecting more than 25 million hectares and resulting in huge yield losses.
Chemical control approaches, including seed treatment and fungicides, have provided acceptable spot blotch control. However, their use is unaffordable to resource-poor farmers and poses a hazard to health and the environment. In addition, “abiotic stresses like heat and drought that are widely prevalent in South Asia compound the problem, making varietal genetic resistance the last resort of farmers to combat this disease,” according to Pawan Singh, Head of Wheat Pathology at the International Maize and Wheat Improvement Center (CIMMYT). Therefore, one of CIMMYT’s wheat research focus areas is developing wheat varieties that carry genetic resistance to the disease.
Signs of spot blotch on wheat. (Photo: Philomin Juliana/CIMMYT)
The study’s results are positive and confirmed that:
Many advanced CIMMYT breeding lines have moderate to high resistance to spot blotch.
Resistance to the disease is conferred quantitatively by several minor genomic regions that act together in an additive manner to confer resistance.
There is an association of the 2NS translocation from the wild species Aegilops ventricosa with spot blotch resistance.
There is also an association of the spot blotch favorable alleles at the 2NS translocation, and two markers on the telomeric end of chromosome 3BS with grain yield evaluated in multiple environments, implying that selection for favorable alleles at these markers could help obtain higher grain yield and spot blotch resistance.
“Considering the persistent threat of spot blotch to resource-poor farmers in South Asia, further research and breeding efforts to improve genetic resistance to the disease, identify novel sources of resistance by screening different germplasm, and selecting for genomic regions with minor effects using selection tools like genomic selection is essential,” explained Philomin Juliana, Molecular Breeder and Quantitative Geneticist at CIMMYT.
Cover photo: Researchers evaluate wheat for spot blotch at CIMMYT’s experimental station in Agua Fría, Jiutepec, Morelos state, Mexico. (Photo: Xinyao He and Pawan Singh/CIMMYT)
There is growing awareness that not all rural women are alike and that social norms and technological interventions affect women from different castes in distinct ways. The caste system in South Asia, which dates back over 3,000 years, divides society into thousands of hierarchical, mostly endogamous groups. Non-marginalized castes are classified as “general caste” while those living in the social margins are categorized as “scheduled caste” and “scheduled tribe”. Scheduled caste and scheduled tribe farmers face both social and economic marginalization and limited access to information and markets, despite government efforts to level up social inequalities.
In India, women of all castes are involved in farming activities, although their caste identity regulates the degree of participation. General caste women are less likely to be engaged in farming than women of lower castes. Despite their level of participation across caste groups, women are rarely recognized as “farmers” (Kisan) in Indian rurality, which restricts their access to inputs, information and markets.
Gender experts from the International Maize and Wheat Improvement Center (CIMMYT) and partners investigated caste-gender relations among wheat farmers in Madhya Pradesh, India’s second-largest state by area. The team conducted focus group discussions and interviews in a village community, and carried out a review of GENNOVATE research in the same area. The team also carried out a survey involving about 800 wheat farmers from 18 village communities across the state.
Women work in the fields in India’s Madhya Pradesh state. Our study found that women are involved in all aspects of agricultural work on family farms. (Photo: CIMMYT)
The study, published last month in Gender, Technology, and Development, revealed five key findings:
First, caste distinctions are sharp. There is little interaction between women and men farmers from the scheduled caste category — even between subcastes in this category — and other castes. They live in separate enclaves, and land belonging to scheduled caste farmers is less fertile than others.
Second, all women are fully involved in all aspects of agricultural work on the family farm throughout the year.
Third, despite their strong participation in farming activities, women across caste groups are normatively excluded from agricultural decision-making in the household. Having said that, the findings were very clear that some individual women experience greater participation than others. Although women are excluded from formal agricultural information networks, they share knowledge with each other, particularly within caste groups.
Fourth, about 20 years ago, women across caste groups were being employed as hired agricultural laborers. Over the past four years, increasing mechanization is pushing many women off the field. While scheduled caste women compensate for the employment loss to a certain degree by participating in non-farm activities, general caste women are not able to move beyond the village and secure work elsewhere due to cultural norms. Women therefore face a collapse in their autonomy.
Fifth, gender poses a greater constraint than caste in determining an individual’s ability to make decisions about farm and non-farm related activities. However, a significant difference exists across the caste groups, presenting a strong case for intersectionality.
Challenging social norms in agriculture
The results of the study show that caste matters in the gendered evaluations of agricultural technologies and demonstrates the importance of studying women’s contributions and roles in wheat farming in South Asia.
Agriculture in India is also considered to be broadly feminizing, with men increasingly taking up off-farm activities, leaving women to as primary cultivators on family fields and as hired laborers. However, rural advisory services, policy makers, and other research and development organizations are lagging behind in recognizing and reacting appropriately to these gendered changes. Many still carry outdated social norms which view men as the main decision-makers and workers on farms.
Funding for this study was provided by the Collaborative Platform for Gender Research under the CGIAR Program on Policies, Institutions, and Markets as well as the International Development Research Center of the Government of Canada, the CGIAR Research Programme on Wheat (CRP WHEAT https://wheat.org/), CIMMYT and the Indian Council of Agricultural Research (ICAR). The paper additionally drew on GENNOVATE data collected in India in 2015–16 with financial support from CRP WHEAT. Development of the GENNOVATE research methodology was supported by the CGIAR Gender and Agricultural Research Network, the World Bank, and the CRP WHEAT and CRP MAIZE, and data analysis was supported by the Bill and Melinda Gates Foundation.
Cover photo: A woman harvests wheat in Madhya Pradesh, India. (Photo: CIMMYT)
Genomic selection identifies individual plants based on the information from molecular markers, DNA signposts for genes of interest, that are distributed densely throughout the wheat genome. For wheat blast, the results can help predict which wheat lines hold promise as providers of blast resistance for future crosses and those that can be advanced to the next generation after selection.
In this study, scientists from the International Maize and Wheat Improvement Center (CIMMYT) and partners evaluated genomic selection by combining genotypic data with extensive and precise field data on wheat blast responses for three sets of genetically diverse wheat lines and varieties, more than 700 in all, grown by partners at locations in Bangladesh and Bolivia over several crop cycles.
The study also compared the use of a small number of molecular markers linked to the 2NS translocation, a chromosome segment from the grass species Aegilops ventricosa that was introduced into wheat in the 1980s and is a strong and stable source of blast resistance, with predictions using thousands of genome-wide markers. The outcome confirms that, in environments where wheat blast resistance is determined by the 2NS translocation, genotyping using one-to-few markers tagging the translocation is enough to predict the blast response of wheat lines.
Finally, the authors found that selection based on a few wheat blast-associated molecular markers retained 89% of lines that were also selected using field performance data, and discarded 92% of those that were discarded based on field performance data. Thus, both marker-assisted selection and genomic selection offer viable alternatives to the slower and more expensive field screening of many thousands of wheat lines in hot-spot locations for the disease, particularly at early stages of breeding, and can speed the development of blast-resistant wheat varieties.
The research was conducted by scientists from the International Maize and Wheat Improvement Center (CIMMYT), the Bangladesh Wheat and Maize Research Institute (BWMRI), the Instituto Nacional de Innovación Agropecuaria y Forestal (INIAF) of Bolivia, the Borlaug Institute for South Asia (BISA) and the Indian Council of Agricultural Research (ICAR) in India, the Swedish University of Agricultural Sciences (Alnarp), and Kansas State University in the USA. Funding for the study was provided by the Bill & Melinda Gates Foundation, the Foreign and Commonwealth Development Office of the United Kingdom, the U.S. Agency for International Development (USAID), the CGIAR Research Program on Wheat (WHEAT), the Indian Council of Agricultural Research (ICAR), the Swedish Research Council, and the Australian Centre for International Agricultural Research (ACIAR).
Cover photo: A researcher from Bangladesh shows blast infected wheat spikes and explains how the disease directly attacks the grain. (Photo: Chris Knight/Cornell University)
The current focus in nutritional circles on micronutrient malnutrition and unhealthy eating habits has raised questions about continuing to invest in research on energy-rich cereal crops and related farming systems.
In this new paper in the International Journal of Agricultural Sustainability, development scientists make the case that cereal foods are an important vehicle for enhanced nutrition – with additional improvement possible through plant breeding and interventions in processing, manufacturing and distribution. It also explains cereals are a rich source of both dietary fiber and a range of bioactive food components that are essential for good health and well-being.
The authors suggest a balanced, integrated research approach to support the sustainable production of both nutrient-rich crops and the basic cereals used in humanity’s most widely consumed and popular foods.
Rice-wheat cropping rotations are the major agri-food system of the Indo-Gangetic Plains of South Asia, occupying the region known as the “food basket” of India. The continuous rice-wheat farming system is deceptively productive, however, under conventional management practices.
Over-exploitation of resources leaves little doubt that this system is unsustainable, evidenced by the rapid decline in soil and water resources, and environmental quality. Furthermore, continuous cultivation of the same two crops over the last five decades has allowed certain weed species to adapt and proliferate. This adversely affects resource-use efficiency and crop productivity, and has proven to negatively influence wheat production in the Western Indo-Gangetic Plains under conventional wheat management systems.
Studies suggest weed infestations could reduce wheat yields by 50-100% across the South Asian Indo-Gangetic Plains. Globally, yield losses from weeds reach 40%, which is more than the effects of diseases, insects, and pests combined.
Herbicides are not just expensive and environmentally hazardous, but this method of chemical control is becoming less reliable as some weeds become resistant to an increasing number common herbicides. Considering the food security implications of weed overgrowth, weed management is becoming increasingly important in future cropping systems.
How can weeds be managed sustainably?
Climate-smart agriculture-based management practices are becoming a viable and sustainable alternative to conventional rice-wheat cropping systems across South Asia, leading to better resource conservation and yield stability. In addition to zero-tillage and crop residue retention, crop diversification, precise water and nutrient management, and timing of interventions are all important indicators of climate-smart agriculture.
In a recently published 8-year study, scientists observed weed density and diversity under six different management scenarios with varying conditions. Conditions ranged from conventional, tillage-based rice-wheat system with flood irrigation (scenario one), to zero-tillage-based maize-wheat-mung bean systems with subsurface drip irrigation (scenario 6). Each scenario increased in their climate-smart agriculture characteristics all the way to fully climate-smart systems.
At the end of 8 years, scenario six had the lowest weed density, saw the most abundant species decrease dramatically, and seven weed species vanish entirely. Scenario one, with conventional rice-wheat systems with tillage and flooding, experienced the highest weed density and infestation. This study highlights the potential of climate-smart agriculture as a promising solution for weed suppression in northwestern India.
Uganda is one of the fastest economically growing nations in sub-Saharan Africa and is in the midst of socio-economic transition. Over the past two decades the country’s GDP has expanded, on average, by more than 6% each year, with per capita GDP reaching $710 in 2019. Researchers project that this will continue to rise at a rate of 5.6% each year for the next decade, reaching approximately $984 by the year 2031.
This growth is mirrored by a rising population and rapid urbanization within the country. In 2019, 24.4% of the Uganda’s 44.3 million citizens were living in urban areas. By 2030, population is projected to rise to 58-61 million, 31% of whom are expected to live in towns and cities.
“Changes in population, urbanization and GDP growth rate all affect the dietary intake pattern of a country,” says Khondoker Mottaleb, an economist at the International Maize and Wheat Improvement Center (CIMMYT). “Economic and demographic changes will have significant impacts on the agricultural sector, which will be challenged to produce and supply more and better food at affordable prices.”
This could leave Uganda in a precarious position.
In a new study, Mottaleb and a team of collaborators project Uganda’s future food demand, and the potential implications for achieving the United Nations Sustainable Development Goal of zero hunger by 2030.
The authors assess the future demand for major food items, using information from 8,424 households collected through three rounds of Uganda’s Living Standards Measurement Study — Integrated Surveys on Agriculture (LSMS-ISA). They focus on nationwide demand for traditional foods like matooke (cooking banana), cassava and sweet potato, as well as cereals like maize, wheat and rice — consumption of which has been rising alongside incomes and urbanization.
A conceptual framework of changing food demand in the Global South. (Graphic: CIMMYT)
The study findings confirm that with increases in income and demographic changes, the demand for these food items will increase drastically. In 2018, aggregate consumption was 3.3 million metric tons (MMT) of matooke, 4.7 MMT of cassava and sweet potato, 1.97 MMT of maize and coarse grains, and 0.94 MMT of wheat and rice. Using the Quadratic Almost Ideal Demand System (QUAIDS) estimation approach, the authors show that in 2030 demand could be as high as 8.1 MMT for matooke, 10.5 MMT for cassava and sweet potato, 9.5 MT for maize and coarse grains, and 4 MMT for wheat and rice.
Worryingly, Mottaleb and his team explain that while demand for all the items examined in the study increases, the overall yield growth rate for major crops is stagnating as a result of land degradation, climate extremes and rural out-migration. For example, the yield growth rate for matooke has reduced from +0.21% per year from 1962-1989 to -0.90% from 1990-2019.
As such, the authors call for increased investment in Uganda’s agricultural sector to enhance domestic production capacity, meet the growing demand for food outlined in the study, improve the livelihoods of resource-poor farmers, and eliminate hunger.
In the plains area of Nepal’s Terai and in larger valleys in the hills, many parts of rice and wheat grain production process are nearly 100% mechanized. The second half of wheat and rice harvesting –– threshing and cleaning –– was mechanized as early as the 1960s. By the mid-1990s nearly 100% of wheat in the Terai was being threshed mostly by stand-alone threshers that were powered by 5-8 horsepower (HP) diesel pumpset engines.
Rice threshing began first in the far eastern Terai in early 2000s with similarly small-sized rice threshers with pumpset engines. However, by the 2010s as 4WTs became ubiquitous in the Terai, the larger horsepower tractor power take-off (PTO) driven wheat and rice threshers became prominent
However, one of the main parts of the production process, the field harvesting of grain, is still not yet fully mechanized even though it is has one of the largest labor requirements. Grain harvesting machinery entered Nepal from India in the late 1990s with the introduction of large 90+ horsepower self-propelled combines in central Terai (Parasi, Rupandehi and Kapilvastu Districts), mainly for wheat. Machines for rice harvesting were introduced in the Western Terai by the 2010s.
In the last decade, the types and numbers of powered or mechanized harvest technologies in Nepal has greatly increased in size. With advent of many new machines from China and elsewhere, the market for grain harvest machinery has become very dynamic. Nevertheless, various bottlenecks limit access and usage far below demand.
A new study by researchers from the Cereal Systems Initiative for South Asia (CSISA), a project led by the International Maize and Wheat Improvement Center (CIMMYT), provides the results of a study on the value chains of rice, wheat and maize harvesting equipment that are used in Nepal by farmers and service providers. It documents the movement of the various new technologies into the value chain, characterizing the whole harvesting machinery market.
The study also provides a detailed value chain map of the various reaper-harvesters, threshers, shellers and combine harvesters that are now widely available for sale in Nepal with the overall goal of providing recommendations for policy makers and development agencies to promote greater access to and usage of such machinery.
