Breeding Cowpeas for Efficient Acquisition and Use of Phosphorus From Low-P Soils and Rock Phosphate.

In the wake of rising fertilizer prices and environmental concerns, efforts are being made to develop crop varieties with better nutrients acquisition and use efficiencies to ensure higher yields and improved sustainability in production systems.  These characteristics are especially important in the semi-arid tropics and sub-tropics where soils are inherently low in nitrogen and phosphorus. Cowpea does not require nitrogen fertilizer because of its ability for biological nitrogen fixation (BNF), and it also has the ability to extract bound phosphorus from low-P soils and from rock phosphate. Therefore, a project has been initiated at Texas A&M University with collaborators in West Africa to develop high yielding cowpea varieties with high BNF activity and enhanced acquisition and efficient utilization of phosphorus from low-P soils and rock phosphate.  Field and greenhouse screening of cowpea germplasm lines have shown major varietal differences for growth and biomass production under low-P and rock phosphate treatments. Some of the promising cowpea varieties are IT97K-1069-6, IT98K-476-8, TX 2028-1-3-1 and Big John. Systematic genetic and physiological studies are underway to elucidate the inheritance  and the mechanism of enhanced acquisition and efficient use of phosphorus from low-P soils and rock phosphate. The details will be presented and discussed.