Search National Agricultural Library Digital Collections
Back to Search
NALDC Record Details:
Field-based Selection Method Creates Alfalfa Populations That Differ in Nitrate Nitrogen Uptake
Sustainable agricultural systems could benefit from alfalfa (Medicago sativa L.) germplasm that reduce N losses to the ground water and decrease N fertilizer inputs. With the goal of producing alfalfa populations with altered nitrate N uptake, our objectives were to develop, assess, and refine an inexpensive selection method using Br- as an analog for nitrate under field conditions. Two selection schemes using divergent herbage Br- concentration and/or divergent herbage Br- uptake, both in combination with high herbage N content, produced two Cycle 1 and four Cycle 2 alfalfa populations. We evaluated these populations for both Br- uptake and nitrate N uptake (estimated by N derived from fertilizer, Ndff [15N-labeled]) for one regrowth period in two locations in each of 2 yr. Weak associations between Br- uptake and Ndff were found during the establishment year, but strong correlations were found between Br- concentration and fraction of Ndff (fNdff) (r = 0.83) and between Br- uptake and Ndff (r = 0.85 to 0.90) when populations were evaluated during the first production year. Populations selected for high Br- concentration or uptake had greater Br- concentration and uptake, fNdff, and Ndff than populations selected for low Br-. Our method of selecting alfalfa plants for differences in herbage Br- concentration or uptake in combination with high herbage N content is the first to successfully produce alfalfa populations that differ in nitrate N uptake in a field environment.
Crop science 2008 Mar-Apr, v. 48, no. 2
Journal Articles, USDA Authors, Peer-Reviewed
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Agricultural Research Service
Web Policies and Important Links