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Philip Roberts

Professor and Chair of Nematology
Philip Roberts
Creating Sustainable, Drought-Resistant Crops
For many parts of Africa, the livelihood of an entire community is closely linked to the quality of that season’s harvest. UCR Professors Philip Roberts and Timothy Close have devoted a great deal of their research efforts to improving the cowpea (also known as the black-eyed pea). As a legume, the cowpea plays a critical role in nutrition, complementing cereals like maize to provide a full amino acid balance in the diet. However, on average, the crop is only performing at twenty percent of its genetic potential. Roberts and Close are working diligently to improve this number by genetically selecting and accentuating favorable traits such as resistance to drought, pests and disease.

Areas of Expertise

Select Honors and Distinctions

  • CIBA Award, Society of Nematologists, 1994
  • Fellow, American Association for the Advancement of Science, 2001
  • Fellow, Society of Nematologists, 2004


Q: What is the goal of your research?
Our current research is focused on cowpeas—a very important grain legume, particularly in developing countries. At present, we’re focusing a lot of our efforts on areas in Sub-Saharan Africa. Our goal is to improve the productivity and nutritional quality of cowpeas through genetic modification, thereby positively impacting the lives of people living in those developing areas.

Q: Why did you select cowpeas (“black-eyed peas”) as a focus for your research?
Like most legumes, the cowpea is nutritionally rich, and for many people living in Sub-Saharan Africa, it is a critically important part of the diet, especially because there is very little meat in the diet. When you combine legumes with cereals, you get a complete amino acid balance. Amino acids are essential for us to make proteins, which play a vital role in the body supporting structural elements (bones and fingernails) and helping us carry out all of our biochemical functions. There are nine amino acids that our bodies cannot make, so we have to get them from our food. Cowpea, as a legume, significantly contributes two amino acids that are fairly poor in cereal plants: lysine and tryptophan. As a complement, cereal plants contribute methionine—an amino acid in which cowpeas are fairly deficient. So together, the cereal-legume combination provides a full amino acid balance.

In addition, there is already a great deal of naturally existing variation in cowpeas around the world. This means that there are a lot of previously-untapped potential benefits that could come of selectively cross-breeding cowpeas to accentuate favorable traits such as drought tolerance and resistance to pests and diseases. At UCR we maintain a cowpea germplasm collection of about 6000 entries, for use as a research and breeding resource.

Q: What are some of the potential impacts of your research?
Aside from the nutritional benefits, enabling farmers to grow high-yielding good quality cowpeas can help them to produce more than what is strictly needed for feeding their families and villages. This additional productivity can have profound and far-reaching economic benefits for individuals and communities, as it provides another source of supplementary and sustainable income when sold in domestic and export markets.

Due to environmental stresses such as drought, pests and diseases, cowpea production in Africa is only performing at about twenty percent of its genetic potential. This means that there is huge potential for improvement through cowpea breeding to develop higher-yielding varieties. That is why the objectives of our program are focused on characterizing the traits of drought tolerance and pest and disease resistance, and developing the genomic resources necessary to breed those beneficial traits into improved cowpea varieties.

Q: What role does your research play in sustainability?
Our research focuses on creating more efficient drought- and pest-resistant cowpea crops, and like other legumes, the cowpea leaves behind additional nitrogen in the soil. This is very useful for growing alternate crops, where you might rotate between growing a cereal and legume in the same soil. We also provide training opportunities for both young and senior plant breeders in Africa under our collaborative projects, and they in turn provide training for better equipping seed producers and production farmers in Africa.

Plant breeding plays another important role in sustainability. If we can offer improved plant varieties that are more resistant to pests and drought, we can conserve water and reduce the number of pesticides necessary to produce the crops.

Q: How is your research currently being used?
The most tangible use of our research is the cowpea varieties we’ve produced. Currently, we have programs in five African countries: Senegal, Ghana, Burkina Faso, Nigeria and Mozambique. Recently, with our collaborators in Senegal, we released three white large-seeded cowpea varieties, and new cowpea varieties are being released in the other countries. We’re very hopeful that these will produce high-yield harvests and gain wide consumer acceptance.

Q: What’s next for your research?
We’re working to make a much denser genetic map for cowpeas containing thousands of molecular markers, as this will give us more precision in the breeding effort and help us to effectively target the traits we want to accentuate or diminish.

Q: Why is UCR a great place to do research?
UCR has a rich history in agricultural research. We have great resources at our disposal, including field station facilities both on campus and down in the Coachella Valley, where the environment is analogous to the one we have in Africa. That, in combination with the Institute for Integrative Genome Biology and other facilities and faculty expertise we have on campus, enables us to continue doing cutting edge research and to test the products of our research in the real world.

Q: What does “Living the Promise” mean to you?
To me, it’s a commitment from both the faculty and the students to come together and give their very best, whether it be in the research lab, the classroom, or the community.

Philip Roberts “Our research on cowpeas is important because we can positively impact the lives of millions of people by improving the quality of their diet.”

—Philip Roberts
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