California Ag Network

Tag: American Society of Agronomy

  • American Society of Agronomy Partners with Natural Resources Conservation Service

    The American Society of Agronomy (ASA) announces its partnership with U.S. Department of Agriculture’s (USDA) Natural Resources Conservation Service (NRCS) to expand conservation technical assistance capacity.

    ASA and NRCS recently signed a Memorandums of Understanding (MOU) that furthers conversation efforts targeted at improving nutrient management. With this MOU, ASA and its International Certified Crop Adviser (ICCA) program establish a framework enabling ASA to recommend individuals for the NRCS Technical Service Provider (TSP) program. The TSP program enables certified individuals outside of NRCS to provide, among other things, nutrient management plans to producers and landowners.

    ”The ICCA Program is excited to continue our over 20-year relationship with USDA NRCS TSP. This new version of the MOU will create a more streamlined process for Certified Crop Advisers (CCA) and Certified Professional Soil Scientists (CPSS) to engage with and expand NRCS’s workforce to meet the needs of US farmers and landowners to increase their conservation practices,” says Luther Smith, Chief Administrative Officer of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

    As trusted on-farm advisers, CCAs are uniquely positioned to become TSPs and assist producers with activities and planning related to nutrient management, soil health, integrated pest management, organics, and grazing management. Technical service providers (TSPs) offer planning, design, and implementation services to agricultural producers such as farmers, ranchers, and private forest landowners on behalf of the Natural Resources Conservation Service (NRCS). This assistance helps improve the producer’s operation.

    “There are simply not enough TSPs certified currently to cover the increasing workload for the various conservation practices that NRCS will be funding in coming years,” says Dennis Godar, CPAg/CCA. “The MOU between ASA and NRCS is very encouraging and timely to increase numbers by certifying qualified CCAs as TSPs. CCAs are highly trained individuals and trusted advisors already familiar with their clients’ operations. It makes sense to strengthen relationships between NRCS, CCA-TSPs, and farmers/landowners.” Godar has been a TSP since 2003.

    The MOU will benefit ASA by providing ASA/ICCA certified individuals the opportunity to become accepted by NRCS as a TSP through recognition of ASA/ICCA requirements. NRCS will place ASA certified TSPs on the approved list to provide technical service to USDA conservation program participants, thereby expanding their scope of services to existing and future clientele.

    American Society of Agronomy: This professional membership society represents researchers and professionals who specialize in growing our world’s food supply while protecting our environment. Together members work toward solutions to advance scientific knowledge in the areas of agronomy, crop science, and soil science.

  • Getting to the Root of How to Grow Cowpea in Difficult, Dry Conditions

    Cowpea is an important crop in many parts of the world, especially sub-Saharan Africa. It is resilient and can grow in areas with little rainfall and low-quality soils. But as hardy as it is, cowpea yields can decrease by drought and low levels of soil phosphorus.

    A high-resolution root hair image taken from a cowpea seedling root sample. The image was taken after 14 days of growth on germination papers. Root hairs play important roles in cowpea tolerance to drought and poor soils. Credit: Saba Mohammed

    In a recent study, researchers determined cowpea root characteristics that could help the plants grow better in drier, low-phosphorus soils.

    “Developing cowpea varieties that can produce optimally under stressful conditions is vital,” says Saba Mohammed, lead author of the study at Ahmadu Bello University in Zaria, Nigeria. “These resilient cowpea varieties can help make more people food and nutrition secure.”

    The study was published in Crop Science, a publication of the Crop Science Society of America.

    Cowpeas are a key source of calories for millions of people across the world. They are rich in protein and other nutrients. Cowpea plants also have a variety of other uses. They can serve as animal fodder and green manure.

    Microbes in cowpea root nodules can increase soil fertility. These microbes make atmospheric nitrogen available to plants in the soil – a process called nitrogen fixation. Nitrogen fixation can be beneficial for farmers who cannot afford nitrogen-based fertilizers.

    Most cowpeas production is in semi-arid regions. Harsh environmental conditions and poor soils often hamper yields. “Our work established that certain root characteristics increased the yield of cowpea plants under drought or low soil phosphorus conditions,” says Mohammed.

    These root features include longer primary roots and higher numbers of lateral roots emerging from primary roots. Root hairs also play important roles in cowpea tolerance to drought and poor soils.

    For example, cowpea plants with longer, denser root hairs had higher yields when grown in low-phosphorus conditions. “That suggests these root hair features play crucial roles in acquiring phosphorus from sub-optimal soils,” says Mohammed.

    Scientists have long known that roots are a key part of how plants adapt to difficult environmental conditions. “The root system is half of the whole plant system,” says Mohammed. “Yet, it has been relatively under-explored in finding solutions to farming constraints.”

    Root systems have diverse strategies for extracting resources from soil. “For instance, plants with deeper roots produce better than those with shallow roots under limited water conditions,” he says. “On the other hand, those with shallow roots may be more suited to soils with suboptimal nutrients.”

    A field experiment on cowpea at the Institute for Agricultural Research in Minjibir Agricultural Research Station, Kano State, Nigeria. Cowpea crops are resilient and can grow in areas with little rainfall and low-quality soils. Credit: Saba Mohammed

    That’s because nutrients – like phosphorus – are often concentrated in the top layer of soil.

    For cowpea plants growing in dry and nutrient-limited soils, roots need to go deeper and spread wide and shallow.

    “Our study shows that we can focus on cowpea varieties with longer taproots for drought tolerance and higher numbers of shallower basal roots to extract soil nutrients,” says Mohammed.

    While root architecture can provide valuable information, examining root features of mature plants can be a time-consuming and exhausting process. Mohammed says it is easier and more economical to phenotype roots at the seedling stage.

    The study showed that examining roots of cowpea seedlings could help identify root features in mature plants that are beneficial for growth in challenging environments.

    “Our goal is to use the study results to breed new cowpea varieties,” says Mohammed. “These new varieties would perform optimally under limited water and low soil phosphorus conditions.”

    Many small-scale and subsistence farmers may be unable to afford phosphate fertilizers. The new cowpea varieties Mohammed describes would benefit these farmers tremendously. However, he explains that developing new varieties with desired root features can also be a valuable resource in systems where intensive irrigation and fertilizers are used. These cowpea varieties can help reduce production costs and minimize environmental pollution from excessive fertilizer use.

    American Society of Agronomy, Soil Science Society of America, Crop Science Society of America: Collectively, these Societies represent more than 12,000 individual members around the world. Members are researchers and professionals in the areas of growing our world’s food supply while protecting our environment. Together we work toward solutions to advance scientific knowledge in the areas of agronomy, crop science, and soil science.

  • How Young Soil Supports Plant Life with Naturally Occurring Fungus

    In order to grow well, plants need a place to grow, access to nutrients, and in most cases sunlight. A rich soil provides that home and a good supply of nutrients. But young soils have less to offer – yes, soils can have different ages ranging from hundreds, to thousands, to millions of years old. According to soil scientist and Soil Science Society of America’s (SSSA) blogger Madhav Dhakal, soil is being made and lost all the time, with various dynamic processes.

    The process of soil formation is often given the acronym ClORPT for: climate, organisms, relief, parent material and time. Soils in warmer climates tend to be older than ones in colder climates. Many organisms, like microbes or insects, help aid soil formation. The term “relief” refers to the topography area. So, usually soil at the bottom of a mountain range – exposed to less erosion and warmer weather, will be older than soil at the top of a mountain.

    The major parent material for soils are rocks. Soil formation takes place after a gradual exposure of rocks to the elements and activity of organism – called weathering.

    One important thing to consider during this whole transformation is time. Time is relatively long for the formation of soil. It happens over geologic time – or millions of years. Over these long periods, landscapes and soils are continuously transforming from one form to another. With time, soil forms different horizons or layers, parallel to the earth’s surface.

    However, soils of recent origin may not contain a distinct horizons or formations. For example, Entisol and Inceptisol are among the 12 soil orders in the U.S. Soil Taxonomy that contain no or very weak horizons or layers of soil.

    In addition to the variety and ages of soils as a home for plants, plants themselves have different types of adaptability. For millions of years, the plant kingdom endured several catastrophic events, geological changes, and climatic extremes. Plants were able to adopt to incredibly different types of surfaces or soil, where the soil itself is highly dynamic and changeable.

    The versatility of plant species may have allowed them to survive in extreme conditions such as hostile climate, rocky, acidic, and salty surfaces.

    There are nearly 435,000 unique land-dwelling species of plants in the world. Some of them grow with very little ingredients or even without sufficient water. For example, some cactus species thrive in the desert. Similarly, lithophytes can grow either on the surface of rocks or in crevices.

    What is it about some plants that allows them to grow in unfavorable conditions? There are a few things. Rock felt ferns, orchids, and liverworts can grow on a rocky substrate, with different tactics or physiological adaptation. They are even capable of feeding off the nutrients from rainwater and nearby decomposed plants, including their own dead cells.

    Lithophytes are a type of plant that grows well on rock surfaces. For most of the lithophytes, the nutrient nitrogen is available from the atmosphere in the form of ammonia. Lithophytes have a smaller number of root hairs and larger root diameters compared to common plant species. This makes them able to efficiently absorb nutrients.

    Lithophytes are a type of plant that grows well on rock surfaces. For most of the lithophytes, the nutrient nitrogen is available from the atmosphere in the form of ammonia. Lithophytes have a smaller number of root hairs and larger root diameters compared to common plant species. Provided by Madhav Dhakal

    Other plants have developed cooperative relationships with soil microbes, which may help them survive in younger soils. Cacti can metabolize a type of acid that helps them with photosynthesis. Plants like peas are legumes – and can work with a bacterium in the category of Rhizobium, and this helps them acquire nitrogen.

    Newly formed soils, such as Entisols and Inceptisols can support plant that have these built-in strategies to supplement their essential nutrients. Depending on the parent material, these soils can provide mineral nutrients such as nitrogen, phosphorus, potassium, as well as micronutrients like calcium, iron, zinc, boron, etc.

    Indeed, as adaptable plants colonize these soils, they also start to help build more soil, in conjunction with microbial and insect activity. Their dead roots and waste products become organic matter, building up the soil bit by bit. One example of how plants can improve soils is the plant lupine (Lupinus Lepidus). Lupine’s metabolites can neutralize acids produced by volcanic emanations. This makes the soil more habitable by other types of plants that cannot survive in acidic soils. There are hundreds of plant species that can survive on and improve young soils over time.

    The Soil Science Society of America (SSSA) is a progressive international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Based in Madison, WI, and founded in 1936, SSSA is the professional home for 6,000+ members and 1,000+ certified professionals dedicated to advancing the field of soil science. The Society provides information about soils in relation to crop production, environmental quality, ecosystem sustainability, bioremediation, waste management, recycling, and wise land use.

  • Pumpkin Production can Benefit from Conservation Practices

    Pumpkins (Cucurbita pepo) are a common vegetable crop sold at local pumpkin patches and farmers markets, in addition to commercial production. In 2019, the value of harvested pumpkin was worth $180 million.

    In addition to the value of harvested pumpkins for commercial use (canned pumpkin, produce departments, etc.) pumpkins are also a staple crop in agritourism operations. In Kansas alone, there were 409 farms registered in the state in 2020. Agritourism enterprises have shown to benefit communities by connecting consumers with agriculture and help preserve farmland in rural and peri-urban areas.

    Vegetable crop production typically involves smaller acreages than agronomic production. However, farmers often rely on intensive cultivation of soil to prepare the seedbed for planting. Tilling also helps manage weeds.

    Agritourism enterprises have shown to benefit communities by connecting consumers with agriculture and help preserve farmland in rural and peri-urban communities. Shown here, a pumpkin patch where people can pick their own pumpkin as part of fall activities. Credit: Canva Pro

    Over time, extensive tillage can have negative effects on soil structure and microbial properties. Researchers in Kansas recently published a paper studying conservation practices for pumpkin production. The research was published in Soil Science Society of America Journal, a publication of the Soil Science Society of America.

    According to researcher Peter Tomlinson, “no-till production methods have been widely adopted by agronomic (field corn, soybean, wheat, etc.) growers throughout the United States. However, no-till practices for vegetable production in the Central United States are relatively rare. Mid-Atlantic States such as Pennsylvania, Virginia, and Maryland have adopted no-till practices for pumpkin and other large-seeded vegetable crops.”

    The study compared growing pumpkins in a biannual tilled control system with annual tilled systems that used cover crops. “This project is designed to compare systems, rather than individual effects of cover crops or tillage,” says Tomlinson. The authors reported the effects of a three-year project on dynamic soil properties.

    The annual systems used cover crops planted into the soil. They were terminated before planting the pumpkins. The team researched cereal rye and oat alone, as well as cereal rye with other cover crops mixed in. They performed the study over three growing seasons at two sites – Eastern and South-Central Kansas. Both sites have humid climates with warm summers, and loam-type soils.

    A field planted with pumpkins grown in a cover crop system with cereal rye. Cover crops have proven environmental benefits, though many vegetable growers in the Midwest have been slower to adopt this conservation practice. A recent study showed soil health benefits with no reduction in yield. Credit: DeAnn R. Presley

    At each of the study sites, soil health was assessed at two key times; plots were sampled 2-3 weeks after pumpkin planting, and immediately after pumpkin harvest.

    The main soil physical property that was affected by management systems used in this study was an improvement with the use of conservation systems in total soil aggregation and the presence of very large aggregates. Soil aggregates are small particles of soil held together with a glue-like substance. This is usually due to microbial activity. Soil aggregates help in the stability of the soil making it less prone to wind and water erosion.

    “Adding cover crops and reducing tillage in a pumpkin production system can cause a measurable change in soil aggregation in a short period of time, two years in this study,” says Tomlinson.

    “There were few instances where the species or mixture of species influenced the results,” he continues. “Rather, the presence of cover crops in the conservation systems appears to have a more dominant role. The significance of this work is that it demonstrated there can be measurable changes in some dynamic soil properties in the short term (two years). This is within a system that involves a reduction in tillage operations and the addition of cover crops.”

    “We conclude that the use of less tillage and a cover crop in a conservation system is generally beneficial as compared to a conventional system. This study illustrates the potential for improving some soil health parameters in as little as two years,” says Tomlinson. Future research will focus on how the implementation of conservation system across a range of agricultural systems and time scales effect dynamic soil properties.”

    Funding for this research was provided by NRCS Conservation Innovation Grant.

    Cathryn Davis measuring infiltration rates in an oat cover crop during her MS research published in this paper (photo by DeAnn R. Presley)

  • Measuring Nitrogen in Green Manures (Cover Crops)

    A crimson clover plant, which is generally recommended to grow in a mixture of grasses, which was used in this study (photo by Sandra Wayman)

    Both chemical fertilizers and cover crops can help build the nitrogen content in soil. But cover crops come with many other benefits, like improving soil structure and boosting beneficial microbes. Researchers at Cornell University are looking at ways to help breed better cover crops, also known as green manures, that could help farmers in their quest to grow crops in the most sustainable way. Their results were published in Crop Science, a publication of the Crop Science Society of America.

    Katherine Muller and her team are working on strategies to measure nitrogen fixation in breeding programs for two common cover crops: crimson clover and hairy vetch. Both crops can pull nitrogen from the air to help them grow. This is called nitrogen fixation.

    “Green manures are crops used to improve soil fertility,” says Muller. “They help the soil by adding nutrients. We look at legumes, which bring nitrogen into the soil due to their symbiotic relationship with bacteria.”

    The use of legume green manures has been around for thousands of years. However, after the 1950s, chemical fertilizers became the main nitrogen source for farmers in developed countries. This is because two scientists, Haber and Bosch, found a way to pull nitrogen from the air, and make chemical fertilizer.

    Though this type of fertilizer is productive, it also takes energy to make it – and it can easily slip into water bodies if not managed correctly.

    “Cover crops are important ecological management tools,” says Muller. “They foster microbial communities and put nutrients in the soil. Essentially, they help build fertile soil that can supply nutrients when plants need them.”

    The use of cover crops can be risky to farmers because they cannot determine the exact amount of nitrogen supplied to the soil. Chemical fertilizers allow for the exact calculation of the amount of nitrogen applied to a crop. But how much nitrogen is provided by each type of cover crop isn’t a known number.

    The amount of nitrogen supplied by a legume cover crop depends on how well it grows and how much of its nitrogen comes from fixation versus uptake from soil. Currently, cover crop seeds available do not have selective breeding for nitrogen fixation – a valuable trait.

    Plant breeders are working to develop cover crop varieties that reduce the risks and increase benefits to farmers. They hope that better varieties will increase the use of cover crops as an alternative to chemical fertilizer. Nitrogen fixation is one of their top priorities for legume green manures.

    “We aim to help plant breeders develop strategies to target nitrogen fixation in cover crops,” explains Muller. “Because nitrogen fixation is a complicated trait that changes as plants grow, the timing of measurements is important.”

    A root system of a hairy vetch plant, with nodules that contain a symbiotic nitrogen fixing bacteria (Photo by Katherine Muller).

    For farmers, the most important measurement of nitrogen fixation is when the crop is terminated. Legume green manures are usually terminated in the late flowering stage. Earlier termination means the crop is likely to resprout and become a weed. However, breeding programs for hairy vetch and crimson clover cannot take that measurement, as they need to remove the plant before cross-pollination.

    “Our team did a field experiment with an active breeding program,” says Muller. “We collected plant tissues and measured nitrogen fixation. We were able to tell how much of the plant’s nitrogen comes from fixation versus the soil.”

    The team tested three kinds of samples that a plant breeder may take to compare them to the sample most relevant to farmers. They then measured nitrogen fixation by sending their samples to a lab that measures total nitrogen content and the abundance of a naturally occurring stable isotope.

    Nitrogen from soil usually has a higher abundance of the nitrogen stable isotope than nitrogen from fixation. This allows researchers to estimate the proportion of nitrogen a plant obtains from soil versus fixation.

    “Our recommendation is to collect stems from each plant in the early flowering stage to measure the nitrogen fixation via stable isotopes,” says Muller. “This provides a good proxy for nitrogen fixation in whole plants, measured in the late flowering stage that is more relevant to farmers.”

    According to Muller, if breeders are going to add one measurement, it should be this. The proportion of nitrogen obtained by fixation often does not correlate with plant size or other measurements.

    “It is important to measure actual nitrogen fixed in the cover crop because it can vary,” says Muller. “Farmers want to know how much nitrogen they are bringing into their fields. We need to accurately measure and provide this information to help farmers make decisions. We hope our research will encourage more farmers to adopt legumes cover crops as a nitrogen source.”

    Katherine Muller is a postdoctoral researcher at Cornell University. This research was done in conjunction with the Legume Cover Crop Breeding Project, funded by the United States Department of Agriculture.

    American Society of Agronomy, Soil Science Society of America, Crop Science Society of America: Collectively, these Societies represent more than 12,000 individual members around the world. Members are researchers and professionals in the areas of growing our world’s food supply while protecting our environment. Together we work toward solutions to advance scientific knowledge in the areas of agronomy, crop science, and soil science.

  • Why Mix Varieties of Wheat in a Field?

    You’ve probably heard of the value of diversification in your financial portfolio. Having more than one type of financial investment reduces risk of losing all your money. My research involves lowering risks for farmers who grow wheat in a sustainable practice of crop mixtures.

    A typical wheat field is one variety, a monoculture production. This tends to be common because it is the most efficient method. However, this type of specialization often requires additional inputs, fertilizers, pesticides, and other chemicals, to maintain the high yields that is expected of modern agriculture. This, in turn, can cause a cycle of reliance on these chemical inputs.

    Various head diseases are shown among the different varieties of wheat in the study. Credit: Julie Baniszewski

    Consider a wheat field with a severe pest infestation, such as aphids or cereal leaf beetle. Once these pests arrive in susceptible wheat field, chemicals may be required to control the pest before it damages the crop. There is risk to hurting beneficial insects like ladybird beetles that might be able to help control the pests naturally. Even ground beetles could be injured. The farmer must control the aphids, as they can kill a lot of the wheat plants – decreasing the food supply and harming the farmer’s profits. But using pesticides also starts to create a loop of continually needing more pesticide application as “good insects” are controlled along with the pests.

    My work involves an alternative solution that reduces risks for farmers and keeps growing a healthy food supply. Our research group is working to create crop mixture systems. Crop mixtures can be intra-specific, containing the same species, or inter-specific, containing different species.

    Aphids, a common pest in wheat, were lightly glued onto cardstock and monitored for 24 hours to quantify predation by native insects. The card on the right shows that four tiny aphids remain; the card the left shows the aphids were consumed by a ladybird beetle. Credit: Julie Baniszewski

    In many cases, interspecific mixtures, also called polycultures, have a different set of challenges in modern agriculture. It’s difficult to use specialized machinery for multiple crops.

    Intraspecific mixtures can be much easier because farmers can manage them as they would a typical monoculture. In the context of a wheat crop, a mixture would consist of two to four varieties of wheat. Each variety would have a different set of traits. One may be high yielding, another resistant to insect pests and yet another resistant to specific diseases. By combining these different sets of traits, the crop is more consistent year to year. The field is more diverse genetically and better able to reduce or withstand pest abundances and diseases – just like diversifying a stock portfolio.

    A wheat field in one year of the researchers’ experiments. Here, different varieties are noticeable because of physical differences – namely color or hue and if the head has awns on it or not. Credit: Julie Baniszewski

    With these wheat mixtures in mind, we created a three-year field experiment to determine if mixtures could:

    • suppress diseases,
    • increase predation of insect pests and
    • increase yield and economic value.

    Each year, we planted a wheat mixture comprised of four varieties. We compared the mixture results to stands with only the single varieties planted separately. We sprayed only half of each plot with chemical pesticides. This was to measure if the mixtures provided an environmental benefit similar to chemical inputs. We quantified insect predation using aphids, diseases, yield, and economic return over variable costs for each of our plots.

    Shown here is the difference of a fungicide application within one variety. The left side of the photo shows the control side of the plot that had no chemical fungicide applied. The slightly darker coloring of the wheat is largely due to disease. The right side of the photo shows the fungicide-sprayed side of the plot. The lighter coloring is healthier wheat, which often also has a few additional days to mature, thereby increasing yield. Credit: Julie Baniszewski

    The yield results were about the same as similar studies, so no surprises there. We found that fields sprayed with fungicides did have higher yields – but only enough to cover the expenses related to fungicide application.

    Some good results: the mixed variety plots had inhibited spread of foliar disease in the field comparable to the fungicide application. Although the wheat mixture was not the highest yielding, nor did it provide the greatest return over variable costs, it did inhibit disease to an extent consistent with a fungicide application – about 20-25%.

    The value of crop mixtures is both a portfolio diversifier and an insurance policy. Although a higher-yielding, single variety wheat field may do well consistently for several years, having the same genetics in the same field has vulnerabilities. In one of those years, there could be a severe pest or disease outbreak, or a severe drought or climate event that that one variety is vulnerable to.

    By using crop mixtures, we increase the genetic diversity and safeguard against a complete crop failure that could occur with that single variety. The genetic diversity from the other combining varieties in mixtures may have disease or pest resistance and may thrive under otherwise stressful climatic conditions. That is, diverse crop mixtures, like financial portfolios, are more stable than any single variety.

    By Julie Baniszewski, Pennsylvania State University, American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.

  • Research Helps Develop High-Yielding, Drought Tolerant Lines of Chickpea

    Chickpeas are a very important crop and food in India. They are used almost every day in meals and snacks. India is the largest producer, consumer, and importer of chickpeas. And with good reason — they are high in protein, fiber, and vitamins and minerals.

    While India grows about 12 million tons of chickpeas each year, the national yield of the crop has not increased much over time. However, the need for more chickpeas to feed the increasing population continues to grow.

    This is why a group of researchers across several research institutions in India are working to develop high yielding chickpea varieties. The team recently reported their results in The Plant Genome.

    “High yielding varieties will help small-holder farmers by delivering more produce with an option to increase income,” says Rajeev Varshney, member of the Crop Science Society of America. “It is important to develop better varieties that are tolerant to drought and are able to meet the demand.”

    Rajeev Varshney, a research program director at the International Crops Research Institute for the Semi-Arid Tropics, examines a chickpea crop (Credit: ICRISAT)

    Over time, chickpea production has moved from northern India to the central and southern parts of the country, where there is less water. This is in addition to climate change impacting global agriculture.

    Varshney and his collaborators set out to breed new varieties of chickpeas with drought tolerance and higher yields. They used genetic techniques to breed several traits for drought tolerance. They focused on popular chickpea varieties already grown by farmers.

    The team used a common method called introgression, where a popular variety is crossed with a variety with the desired traits. Following a series of evaluations and repeated crossings, the breeders arrived at an improved chickpea variety with the desired traits.

    “However, this conventional process is not very precise, and in this procedure, breeders need to screen a large number of plants in field conditions,” Varshney explains. “For example, if there is a lot of rain in that season, breeders cannot select the line for drought tolerance. It ruins the whole experiment.”

    To combat this, the researchers used a technique called marker-assisted backcrossing. It uses laboratory techniques to detect a genetic marker. Genetic markers are DNA segments associated with certain plant characteristics or agronomic traits desired by farmers.

    By being able to detect certain plant characteristics in the lab using genetic markers, there is no need to do lots of testing every year in the field. It makes the breeding process precise, fast, and cost-effective.

    The work helped incorporate drought tolerance into three popular varieties of chickpeas. Overall, researchers developed six lines of chickpea with higher yields under drought conditions. One line, Pusa Chickpea 10216, has been released for use by Indian farmers.

    “We worked with already released elite varieties that are preferred by farmers,” Varshney says. “By improving these, it’s more likely they will be adopted by farmers in a faster manner.”

    “Here we have demonstrated successful use of using genetic markers to develop drought tolerant chickpea varieties,” Varshney says. “We would like to see this kind of breeding being deployed by our national partners at a large scale in India, Ethiopia, Kenya, Tanzania, and elsewhere.”

    This research shows the public benefits of this kind of genetic research. Maintaining strong public support and funding for the research pipeline allows such work to take place.

    “The work shows how genomics research can be used to develop better high-yielding drought tolerant varieties,” Varshney says.

    Rajeev Varshney is a research program director at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and Adjunct Professor with Murdoch University (Australia). Support for this research was provided by the Government of India through its Department of Biotechnology in the Ministry of Science and Technology, Department of Agriculture, Cooperation & Farmers Welfare in the Ministry of Agriculture & Farmers Welfare, and the Bill & Melinda Gates Foundation.

    Flowers are incredibly striking when in full bloom (Photo by L. Vidyasagar)

    American Society of Agronomy, Soil Science Society of America, Crop Science Society of America: Collectively, these Societies represent more than 12,000 individual members around the world. Members are researchers and professionals in the areas of growing our world’s food supply while protecting our environment. Together we work toward solutions to advance scientific knowledge in the areas of agronomy, crop science, and soil science.

    Twitter: @ASA_CSSA_SSSA & @SSSA_soils | Facebook: ASA, CSSA & SSSA | Instagram: @sustainablefoodsupply & @iheartsoil

  • Celebrating Seed Week – Food Security and Hope

    To bring awareness to the importance of seeds, the Crop Science Society of America is celebrating Seed Week March 22-28, 2021.Seed week logo

    Anyone who plants a seed is investing in hope. That’s one of the attractions of seeds. For the gardener, it could be hope for a beautiful flower, or perhaps a delicious zucchini squash. For our farmers, seeds are the hope of this year’s yields of produce, cash crops or forage. No matter the size or shape of the seed, they all can bring forth new life.

    Seeds also are crucial for the food security of the human population. Scientists keeps seeds in seed banks in case of disaster. They use seeds from different cultivars to breed new crops that are disease resistant. Other attributes for new varieties like drought tolerance and improved shelf life start with the genetic material contained in seeds. Sometimes genetic diversity needs to be stored in other ways, but the large majority of the genetic information of our crops is contained in seeds.

    The content collected for Seed Week includes:

      • Seven new blog posts just for Seed Week, in addition to ones previously published on the Sustainable, Secure Food Blog. Topics include:
      • A collection of CSSA news stories about seed science.
      • A video about a crop scientist who studies seed germination.
      • Science research from journals published by CSSA.
      • A variety of K-12 activities to learn about seeds.
    Seeds in being inspected at the USDA (Photo by Scott Bauer)

    American Society of Agronomy, Soil Science Society of America, Crop Science Society of America: Collectively, these Societies represent more than 12,000 individual members around the world. Members are researchers and professionals in the areas of growing our world’s food supply while protecting our environment. Together we work toward solutions to advance scientific knowledge in the areas of agronomy, crop science, and soil science.

    Twitter: @ASA_CSSA_SSSA & @SSSA_soils | Facebook: ASA, CSSA & SSSA | Instagram: @sustainablefoodsupply & @iheartsoil

  • Helping Stevia Brave the Cold

    It’s a fact – humans love sugar. For those of us who also like to watch our calories, sugar substitutes can help.

    Some zero-calorie or low-calorie sweeteners have attracted bad reputations for containing unnatural ingredients. But there are also natural sweeteners derived from plants, like steviaHands holding snipping tool cutting off a piece of a stevia plant

    Stevia is hundreds of times sweeter than sugar, and it has no calories. The global stevia market is now worth hundreds of millions of dollars.

    The sweetener is derived from the leaves of the plant Stevia rebaudiana, a native of Paraguay and Brazil. The leaves make chemicals similar enough to sugar to trick the tongue. But our body doesn’t burn these chemicals as fuel.

    Todd Wehner is a plant breeder who aims to develop stronger varieties of stevia. These better varieties can help farmers and consumers alike.

    His research was published in Agrosystems, Geosciences & Environment, a journal of the American Society of Agronomy and Crop Science Society of America.

    “The market is growing rapidly as companies and consumers move away from sugar in their diet,” says Wehner.

    Although this tropical plant is grown around the world, it faces hurdles growing in cold climates. Freezing temperatures can dramatically injure or even kill stevia plants in short order. That makes it harder for farmers in countries like the U.S. to grow the sweet crop.

    So, plant breeders like Wehner are interested in finding the hardiest stevia plants out there to help crops brave the cold.

    “As we continue to select varieties that are cold tolerant in our area, new releases will have adaptation to a wider production region,” says Wehner.

    With his teammates, Wehner recently shared findings about the cold tolerance of different stevia varieties. Their results can help scientists breed cold-hardy stevia plants better adapted to the U.S. and other temperate climates.

    To find the strongest plants, the research team subjected 14 varieties of stevia to different cold stress tests. The tests ranged from just below to just above freezing. Plants were exposed to cold for anywhere from 2 to 10 days. After the stress tests, the scientists assessed how much damage the plants sustained.

    A couple varieties were clear standouts in their ability to resist the cold. These varieties might be useful for breeders who want to make cold tolerant stevia crops.

    The plants grew normally after being moved to warmer conditions. This allowed researchers to harvest seeds for the next generation.

    The temperature of the test really mattered for measuring hardiness. Somewhat surprisingly, some varieties that were resistant to temperatures just above freezing were some of the most susceptible to temperatures just below freezing. That finding provides useful information for how breeders should test for cold tolerance in the future.

    “It appears that we will need to select for cold tolerance using a range of temperatures, so that we avoid the problems where a selection is resistant to only one temperature,” says Wehner. “Tests will become a standard part of the breeding program.”

    Wehner and his team are now providing the seeds of the most cold-tolerant varieties to any other interested researchers. Recruiting other scientists to contribute can increase the pace of improvements to stevia.

    The team is also studying other types of improvements to the crop. These include increasing the germination of seeds, beefing up resistance to diseases, and improving the production of leaves and sweetener chemicals.

    “We are continuing to develop new varieties that will be higher yielding and better tasting. New varieties will be less expensive to produce as the genetics are improved for the environments of interest,” says Wehner.

    “For the 95% of humans who like stevia, we are continuing to make these products taste better,” he adds.

    Todd Wehner is a plant breeder at North Carolina State University. This work was supported by PepsiCo and United States Department of Agriculture Specialty Crop Research Initiative grants.

    American Society of Agronomy, Soil Science Society of America, Crop Science Society of America: Collectively, these Societies represent more than 12,000 individual members around the world. Members are researchers and professionals in the areas of growing our world’s food supply while protecting our environment. Together we work toward solutions to advance scientific knowledge in the areas of agronomy, crop science, and soil science.

  • How do Radishes Work as a Cover Crop?

    Farmers love tools. The prospect of a fully stocked tool shed ranges from badge of honor to true obsession.  Plants, too, can be used as tools. Integrating cover crops into a farmer’s toolbox can offer many benefits – and it’s a tool given to us by nature!

    Getting farmers to adopt cover crops as various tools can be hard. To do that, we need to better understand these different tools and their uses. Cover crops like clover add nitrogen to the soil, while reducing erosion and runoff. And, radishes, a tasty ingredient in salad, can be used to break up soil and other hard jobs.

    Breaking up soil with radishes

    Millennia ago, Greek philosophers presented the Doctrine of Signatures, stating that a plant’s appearance may resemble its practical use. For example, walnuts were linked to brain health and beans to kidneys. In thinking about the radish as a tool, the plant root could be similarly equated to the drill, a type of natural tilling.

    Thick radish roots are an ideal choice for natural drilling into the soil to reduce compaction. When the radish crops are terminated, the radish and roots leave large, open pores in the soil. This increases soil aeration and water infiltration. Along with this comes more earthworm and microbial activity. It’s clear that a tillage radish cover crop certainly lives up to that name. As it turns out, the simple radish can be quite the complex tool when properly utilized.

    Scavenging and cleanup

    There are many varieties of radish. From ‘Daikon’ to ‘Icicle’, knowing the specific cultivar is an important part of deciding if a radish belongs in your field or on your plate! When an agronomist recommends a radish variety for use as a cover crop, they have a job in mind to make use of these unique plant features.

    Farmers turn to “scavenging” to optimize chemical inputs and yield outputs by using cover crops. The cylindrical roots of the radish grow deep and capture soil nutrients that were intended for the preceding cash crop.

    Many varieties are uniquely suited for this task, having been bred specifically for deep taproots that extend several inches or even feet deeper than their thick quintessential core. By scavenging nutrients from soil layers that are the hardest for most crop roots to access, radishes can be used to target critical areas to keep nutrients from the groundwater table. Though picky eaters may leave behind a harvested radish on their plate, the radish itself helps ensure that as little as possible goes to waste in terms of subsoil nutrients.

    A Daikon radish cover crop emerges after being seeded into standing corn. Radishes help break up soil compaction and use up extra nutrients to reduce runoff. Credit: Ivan Dozier

    Biofumigation – natural chemical combatants

    In March 1990, Former President George HW Bush personified picky eaters everywhere when he issued the proclamation: “I’m not going to eat any more broccoli!” The president succeeded in banning the brassica from Air Force One and the White House.

    The same pungent flavor that the former President didn’t like is loved by many. And its special compounds called gluconsinolates that give them their flavor. These compounds contain sulfur (like some medicines) and can also act as natural pesticides in the soil, a method known as “biofumigation.” These compounds can be a powerful deterrent to insects and even some species of fungi.

    The choice depends on the job

    When choosing a radish and/or any other cover crop, the most important consideration is to select the right tool for the job! For example, planting a radish in a poorly drained clay soil can drastically restrict the root growth necessary for several of the benefits. Selecting the wrong cover crop is like trying to tighten a bolt with a hammer instead of a wrench, which may explain why some don’t see convincing results.

    When choosing a radish for cover cropping, agronomists recommend that farmers select the right tool (specie) for the right job. Shown, a selection of cover crop radishes with roots. Credit: T&T Seeds

    Successful cover croppers often strengthen their polyculture by adding the radish into a multi-species mix. For those looking for a natural multi-tool to alleviate compaction, scavenge subsoil nutrients, and ward away pests, I can assure you that radishes will not leave you with a bitter taste! — By Ivan A. Dozier, CCA, Product Manager for Agronomy & Analytics at IntelinAir (American Society of Agronomy and Crop Science Society of America)