Beans, also known as cowpea, are an important staple crop in sub-Saharan Africa, serving consumption needs as well as being a good source of quality fodder for livestock. Beans are the fourth most important source of protein in Nigeria and other parts of the world. However, cowpea farmers face a challenge with a traditionally low yield factor due to its susceptibility to many insect pests at different stages of its production lifecycle.To meet the challenge, scientists and research institutions are developing better beans to combat pests, DANIEL ESSIET reports.
Dry beans are a vital staple in Nigeria and other parts of sub-Saharan Africa, providing the main source of dietary protein for more than 70 million people. Nigeria is the largest cowpea/pulses producer in Africa and the fourth largest in the world after India, Canada and Burma.
Despite that it is grown all over the country, only six states – Borno, Zamfara, Sokoto, Kano, Gombe and Yobe – grow the crop commercially. Their produce is not enough for consumption, a reason, Nigeria imports cowpea from Cameroon, Niger and Benin Republic to make up.
Growing beans, also known as cowpea, has many benefits. Its rich nutrient consists of vitamins, minerals and protein, making cowpeas an important food source for many who can’t afford meat. These include supplying 25 to 30 percent of the recommended levels of iron and meeting 25 percent of the daily requirement of magnesium and copper as well as 15 percent of the potassium and zinc requirement, scientists say.
There is a market for common beans in Nigeria. With good agricultural practices, including good soil preparation, using fertiliser, if required, using good seeds, and planting seed at 30-40 kg/acre, farmers can harvest over 800 kg/acre. In the last three years, farmers have been battling harmful pests.
But post-harvest storage loss of beans has been a major challenge among smallholder farmers. It has led to a huge loss of Nigeria’s export market for beans.
In January 2013, the European Union (EU) placed a temporary suspension on dried beans from Nigeria for one year over the excessive use of chemicals by farmers to control a pest, Maruca Vitrata, from damaging crops on the field. Farmers were also found to be over using chemicals and pesticides in preservation of beans, without regards to human health.
However, again in mid-2015, the EU suspended the export of selected Nigerian agricultural produce into their member countries. The details were outlined in the EU regulation 2015/943 as amended by Regulation 2016/874.
The ban was extended by three years from the June 2016 deadline due to the observation of non-compliances to pesticides and other chemicals minimum acceptable residue level of 0.01 milligram/kilogram (mg/kg).It was discovered that Nigerian dried beans still contained high pesticide residues considered dangerous to human health.
Various associations involved in the beans farming space have surged into action to get the ban lifted.
For instance, Cowpea and Beans Farmers, Processors and Marketers Association of Nigeria’s President, Shittu Mohammed, said the association was already putting measures in place to raise the capacity of farmers in best agronomic practices.
“We are trying to get silo from the government for the 36 states, where we can store our beans. We are also working at setting up laboratories in the states where the National Agency for Food and Drug Administration and Control (NAFDAC) can test the beans before export. This is to ensure that no beans go out of the country without properly been tested.
“We are also working to put farmers in clusters to enable them get proper training and access to mechanisation, input, improved varieties and all that they need to increase production,”Mohammed said.
Mohammed explained that the EU ban extension was as a result of farmers who were excessively using chemicals and pesticides for the preservation of beans without regards to human health, a problem which he said, was being dealt with by the association. “You see, the ban was because our farmers were using excess chemicals and pesticides on their dried beans without thinking of the effects on human health,’’ he added.
He urged the government to address the issues of funding and accessibility to market, which he said, is responsible for the application of chemicals to preserve the harvests before the sale. Beans farmers complain about pod borer, the primary bean pest in the field, which have reportedly decimated up to 90 percent of some farmers’ yields. The pod borer can be controlled with insecticides, but they are expensive, not easily accessible to resource-poor farmers, and continuous use results in the advancement of resistance in target pests.
Bean production is a multi-million naira industry. It employs thousands of people.
Given the importance of beans farming, researchers are working to develop improved beans varieties.
Following more than two decades of research, field trials, and risk assessment by multiple organisations, the Nigerian Biosafety Management Agency (NBMA) approved the commercial release of the resulting genetically modified cowpea to farmers in Nigeria.
NBMA’s approval allowed the Institute for Agricultural Research (IAR) to commercially release Pod Borer-Resistant Cowpea (PBR Cowpea)-event AAT709A, genetically improved to resist Maruca Vitrata. The permit is valid until the end of 2022. The release provides a relief to millions of farmers who depend on cowpea for food and income, as well as the consumers of cowpea.
The International Institute for Tropical Agriculture (IITA) Principal Scientist in Plant Biotechnology, Leena Tripathi, expressed delight, stating: “This is indeed good news for IITA and Nigeria at large, as the first GM food crop will be available for commercialisation.”
One of the most damaging insect pests that attack the cowpea plant is the Maruca vitrata, commonly called the Maruca pod borer, which causes 70–90 per cent yield loss for farmers. Due to high costs and, sometimes, unavailability of suitable insecticides, many cowpea farmers resort to harmful cotton insecticides to spray cowpea fields. This has, unfortunately, led to significant numbers of intoxication and deaths.
IITA, which has cowpea as one of its mandate crops, along with other research partners, decided to focus on developing an improved cowpea variety that would be resistant to Maruca. To achieve this, more than 15,000 cowpea varieties in the IITA germplasm bank were evaluated for resistance to Maruca.
Giving an overview of the project, IITA Legume Geneticist and Breeder Christian Fatokun stated that the researchers also evaluated wild relatives of cowpea and although a gene from one of the species called Vigna vexillata was identified to be resistant to maruca, crossing this to cowpea proved unsuccessful.
With the lack of success of conventional breeding for resistance, the collaborators on the project decided to adopt a biotech approach that would result in genetically modified cowpea.
Previous research using a bacterium called Bacillus thuringiensis (Bt) to confer resistance in maize crops had proved quite successful and some of the Bt gene strains have been found to be resistant to Maruca.
With genes provided by Monsanto and initial phases of product development conducted at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia, significant milestones were achieved in developing cowpea lines, expressing the Bt (Cry1Ab) gene that confers resistance to maruca pests. The successes graduated to confined field trials (CFT), which were conducted at IAR in Zaria, Nigeria.
Results from the research have shown that Bt cowpea will reduce the use of pesticides from eight sprays per season to about two targeted sprays and increase yield by up to 20 per cent. This means that Nigeria will record a revenue increase of more than N48 billion yearly from cowpea.
Extensive safety studies have shown that the Bt cowpea is safe for human and livestock consumption.
The research was led by IAR in partnership with the African Agricultural Technology Foundation (AATF) to which Monsanto licensed the Bt gene for use in the project. Other collaborators included Purdue University, United States, CSIRO, Australia; Network for Genetic Improvement of Cowpea for Africa (NGICA), the IFPRI-facilitated Program for Biosafety Systems (PBS) and IITA with support from United States Agency for International Development (USAID).
In a document dated January 22, last year, NBMA stated that it issued the permit after considering the advice of the National Biosafety Committee, the National Biosafety Technical Subcommittee, and the risk assessment and risk management report provided by IAR.
“After a thorough analysis of the application dossier which included Risk Assessment and Risk Management Plan prepared in connection with assessment of the application, it is unlikely that the proposed release will have an adverse impact on the environment and human health,” read part of the document.
So much has been done to improve the quality of beans. These include breeding varieties that resist weevils, a pest that can inflict damage on leaves and seeds.
Through advanced breeding, scientists have developed disease-resistant beans.
An international team of scientists from the African Agricultural Technology Foundation (AATF), in collaboration with local researchers in Africa and advanced laboratories, is working to cultivate cowpea varieties that have in-built insect protection through the use of a gene from bacteria (Bt gene). The Bt gene produces a protein that interferes with the digestive system of legume pod borers, but it is specific to pod borers and safe for all other organisms, including beneficial insects, humans and animals. Bt cowpea lines have been tested in confined field trials in Burkina Faso, Ghana, Malawi and Nigeria, with the tests showing promising results.
Another success story has come from the International Centre for Tropical Agriculture (CIAT), Columbia, South America. It is on the campaign of producing disease-resistant bean varieties that can be bred more rapidly and selectively for the world’s various bean-producing regions. CIAT bean researchers are developing a wide range of varieties for disease resistance. They also aim to combine tolerance to various abiotic stresses (drought and poor soils) through the use of gene discovery, marker-assisted selection, and farmer participatory methods. CIAT distributes the seeds to various sub-organisations who then supply them to breeders.
CIAT safeguards the world’s largest and most diverse collection of bean germplasm. The collection consists of about 36,000 samples of cultivated materials mostly from the crop’s Mesoamerican and Andean centres of origin with wild species related to these materials. The CIAT collection constitutes a valuable resource for bean improvement worldwide.
CIAT has established Pan-Africa Bean Research Alliance (PABRA) to work with farmers to provide better beans for Africa. PABRA is made up of an international network of bean researchers, 29 national agricultural research institutions, and more than 350 partner organisations.
As a result of PABRA’s interventions, more farming families have access to improved and marketable bean varieties, new crop management techniques, micronutrient rich bean-based products, niche market varieties and products, and bean-related skills and knowledge that help to increase incomes and boost food and nutrition security.
Over 550 new bean varieties have been released by PABRA member countries with CIAT assistance across Africa since 1996. Scientists have identified beans that can beat the heat and perform well under at least 3 °C higher average temperatures
Growing more climbing beans, as opposed to lower-yield bush beans, could help increase food security in sub-Saharan Africa as demand for food increases, climate change becomes more pronounced, and arable land becomes scarcer, according to a new study. Researchers mapped suitable cultivation areas and modeled future scenarios for 14 countries.
The results indicate where specialists can target to promote climbing bean cultivation in areas that are highly suitable for the crop and not yet cultivated.
“Climate change is making it more difficult for Africa to produce food,” said a co-author and environmental scientist at Spatial Informatics Group, Glenn Hyman. “Yields are expected to go down. We’re proposing climbing beans as an intensification solution, mostly because they yield three times more than bush beans.”
