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Can you tell us about yourself?
Mr. Brijesh Angira recently and successfully defended his Ph.D. dissertation entitled “Genetic and Physiological Studies of Heat Tolerance in Cowpea.” Brijesh is a native of India and received his B.S. from Acharya N. G. Ranga Agricultural University in India and his M.S. degree from West Texas A&M University. His Ph.D. graduate studies were directed by Dr. Dirk Hays. Brijesh came to Soil and Crop Sciences on a Pathway to Doctorate Fellowship and recently received the Tom Slick Fellowship that is awarded to outstanding Ph.D. graduate students for support of their final year of data collection, analysis, and dissertation development. Below is some information provided by Brijesh about cowpea and about his research. Congratulations Brijesh on your outstanding accomplishments.
Please tell us about your research
Cowpea , also known as black-eyed pea, southern pea, crowder pea, zipper pea (USA), and lobia (India), is widely grown in drier regions of the tropics and sub-tropics of 65 countries. The worldwide area used for growing cowpea is estimated to be over 14 million hectare (ha) with over 7.2 million tons in annual production. In the United States, Southern Europe, and the Middle East, “black-eyed pea” cowpea is dominant, and it is characterized by its large grain and white seed coat with a prominent black pigmented eye. Cowpea was one of the earliest domesticated crops and remains an important annual grain and forage legume.
Cowpea is a multifunctional crop that is used for food (dried seeds or as immature vegetable), feed (grazed or greenchop), and as a cover crop to prevent erosion and improve soil fertility. As a food source, it is an inexpensive source of protein, amino acids (lysine and tryptophan), vitamins, and minerals in the daily diets of millions of people worldwide. In diets around the world where most calories are derived from cereal grains, cowpea provides needed amino acids for human health. In addition to nutritional supplementation in the diet, cowpea improves cropping systems and soil fertility by reducing soil erosion, suppressing weeds, and providing a high nitrogen green manure amendment through its symbiotic rhizobium relationship. It can grow in soils that have a high (more than 85%) sand content and less than 2% organic matter; it is also shade tolerant and compatible as an intercrop with maize, millet, sorghum, sugarcane, and cotton. These features make it an important crop of the complex and subsistence cropping system of the dry savannas in Sub-Saharan Africa. Some recently improved cultivars of cowpea have a short life cycle of 55 to 65 days from seed to seed. Such a short life cycle increases its potential to be an important crop in many existing cropping systems.
Brijesh evaluated 41 varieties of cowpea during the exceptionally hot and dry year of 2011 at College Station and identified significant differences among these varieties for yield potential under high heat field conditions. You’ll recall that 2011 was an exceptional hot and dry year in Texas with record high temperatures and exceptional drought conditions over the majority of the state. He subsequently evaluated 20 of the 41 under greenhouse conditions and during 2012, which was substantially cooler and wetter than 2011. Results indicated variation among these genotypes for resistance to excessive heat. One of most heat tolerant varieties was Golden Eye Cream (GEC) that was developed and released in 2006 by Dr. Creighton Miller at Texas A&M. Brijesh concluded that five genotypes were heat tolerant (IT98K-277-2, GEC, IT98K-1092-1, Yacine, and IT90K-1111- 1) and five of the 20 were consistently heat susceptible (Big John, IT98K-589-2, IT98K-476- 8, CB-46, and UCR-288).
Once Brijesh established that meaningful variation existed among cowpea genotypes for heat tolerance, he selected two contrasting parents, GEC and IT98K-476-8, for additional study. These parents were crossed to produce a RIL (recombinant inbred line) population with the objective of identifying QTL markers for heat tolerance based on seed weight and pod number. These varieties differ in genetic background and are highly polymorphic for several traits. As noted above, GEC (Golden Eye Cream) was developed Tolerant Susceptible variety by Creighton Miller et al. and released in 2006. It is a high yielding medium maturity (66 to 72 day) variety. IT98K-476-8 is a high yielding medium to late maturing (70 to 80 day) variety developed by IITA (International Institute of Tropical Agriculture) in Africa in 1998. These two parents were crossed to develop a mapping population consisting of 175 recombinant inbred lines (RIL) through single seed descent methodology. Brijesh reported a linkage map with 11 linkage groups, which corresponds with the known chromosome number in cowpea, covering 1085 cM. Linkage group 3 and 10 housed a number of consistent QTL’s for heat tolerance or for traits associated with heat tolerance.
How will your research benefit the community?
Brijesh’s work, along with other research being conducted at Texas A&M, will help improve this important crop for many tropical and subtropical environments. It has been and will continue to be an important protein source for many areas in developing nations and it will continue to be a much desired part of diets worldwide.