Feed the Future
This project is part of the U.S. Government's global hunger and food security initiative.

Breeding a Better Cowpea : Q&A with Timothy Close, Director of the Feed the Future Climate-Resilient Cowpea Innovation Lab

This interview is the second in a series with the Feed the Future Innovation Labs for climate, weather and resilient agriculture month this May on Agrilinks. See the previous in the series here

Based at University of California, Riverside, the Feed the Future Climate-Resilient Cowpea Innovation Lab develops and applies advanced genomic tools to cowpea breeding to increase yield, drought tolerance and fungal resistance in cowpea (commonly known as black-eyed peas in the US), a common nutritious staple in African countries. The Climate-Resilient Cowpea Innovation Lab works in the focus countries of Burkina Faso, Ghana, Nigeria, and Senegal.

Agrilinks: Tell me about some of the lab’s successes to date.

CloseThe first big success was establishing a standard set of cowpeas that encompassed the most important breeding germplasm (accessions) currently used within each of the four West African groups. To accomplish this we developed a high-resolution tool, a genotyping assay that looks at 51,000 spots in the cowpea genome, which was used to create a genetic ID of every accession. We also had to reach agreements with all partners to participate in the establishment and distribution of pure seed stocks. We call these the “partner favorites,” which comprise about 170 accessions/varieties. Seeds of the partner favorites were propagated at each designated source location for the master stock, then distributed through 20 international transfers, and then further multiplied at every partner location to enable replicated multi-location field trials.

By combining the data from multiple trials and comparing it to the genetic information, we now have begun to see a few major genetic markers for favorable traits in the context of West African cowpea production. In essence, by working with uniform, genetically identified materials, we have removed the genetic variables from trials in different settings, so we can track consistencies and differences across environments.

The genotyping has required a substantial, sustained effort and has been important for several reasons, including verifying parent and progeny identity, and to check seed purity in general. The number one issue for all of the breeding teams is the ability to ensure the purity and identity of locally grown seeds. This needs to be addressed with various systems upgrades related to seed production, storage and data entry. We are very engaged in standardizing data formats and working toward hosting all of the genetic and field data in a central database housed at the International Institute of  Tropical Agriculture (IITA) in Ibadan, Nigeria. The standardization of data formats is tedious and laborious, but also crucial to ensure future longevity and utility of the information.

IITA holds the world’s largest collection of cowpea germplasm and has the mandate for cowpea within the CGIAR system. Yet, the cowpea effort at IITA is undersupported relative to many other crop plants that are comparable to cowpea in their relevance to worldwide food and nutritional security. Breeding and germplasm management programs often face funding challenges; we want to support the work at IITA by helping to keep materials secure and well defined. This is important for the sustained development of new cowpea varieties to address new challenges from pest, pathogens and environmental fluctuations.

The lab’s work to strengthen the capacity of scientists in-country is also tremendously important. To address this, we like to bring focus-country researchers to our lab stateside for in-depth training, while also providing funding to support in-country graduate training programs.

Agrilinks: What advances have you made in improving cowpea varieties through the genetic material you’ve identified?

Close: We use several types of genetic populations to study the inheritance of traits and develop markers for them, which can be used in the breeding programs. All of the West African teams are breeding cowpeas for rain-fed production, which means tolerance to drought, sometimes also heat, and the suite of biological factors that are associated with water-limited conditions including insects and pathogens. A particularly troubling pathogen of drought-stressed plants is Macrophomina phaseolina, which is a point of emphasis in this Innovation Lab.

The most important factor for adaptation to water-limited environments is the timing of flowering. For example, if severe drought conditions exist during flower development, then pollen development fails and few or no seeds will develop, resulting in a poor yield. So it is important to identify genetic loci that control the time to flowering under a range of daylengths, temperatures and soil moisture content. We have come a long way in mapping such loci in cowpea, culminating in a set of genetic markers for flowering time that can be integrated into what is called “marker-assisted selection” strategies. Numerous other traits now are well marked also, in the range of 50 or so major loci including traits such as insect and pathogen resistance, seed coat characteristics, seed size, plant architecture and seedling stage stress tolerance. This progress has been furthered by the recent development of a complete cowpea genome sequence in a project supported by the National Science Foundation.

Breeding programs all work within a continuum of making crosses, progeny selection, multi-year and multi-location field trials, advanced line development, seed increases, and ultimately the release of new varieties. Release of new varieties requires a strong seed system from breeders seed (the original source) through foundation and certified seed production, and into farmer co-ops and markets. The whole process from first crosses to variety release and adoption takes considerably more than five years, so different lines are at different stages within that continuum at any point in time. Because of the time required from start to end, we have new varieties coming out from each of the West African teams, but all of those new varieties can be tracked back to crosses made from earlier funding.

Agrilinks: What are some key factors contributing to the lab’s successes?

It’s very important to understand things as they are within the breeding teams and build momentum from that platform, taking sustainable but often small steps forward. The latest technological advances and scales of peration that are commonly in use in US labs, private companies and the most advanced international research centers are generally not the most appropriate points of emphasis for national breeding programs in developing countries. To succeed it is necessary to get into details such as whether or not there is reliable electricity and a satisfactory fleet of sturdy vehicles, how pesticides are procured and stored, and how seeds are stored and inventoried, among other things. We had an advantage of decades-long prior relationships with most of the host country teams that are part of this Innovation Lab; these established relationships contributed significantly to our pace of progress.

Seed purity is the number one bottleneck for continued advancement of the West African breeding groups that are part of this Innovation Lab. Every operation requires adequate physical resources and good operating procedures to ensure the production of pure seeds from one season to the next. This requires pollinator-free greenhouses, airtight containers and refrigeration for seed longevity, electronic methods of inventory control, and periodic genotyping to check the fidelity of materials that pass through greenhouses and fields. Most of this is not high tech or exciting, but that’s the reality of having a productive breeding program.