ibclogo XVI International Botanical Congess


Abstract Number: 6062
Session = 3.17.7


PLANT IMPROVEMENT FOR N2 FIXATION


J. E. Harper, USDA/ARS and University of Illinois, Urbana, IL61801, USA


The role of symbiotic N2 fixation has become increasingly important in sustainable agricultural systems. Soil nitrogen availability continues to be primary limitation to symioticN2 fixation by legumes. Results indicate that over coming this limitation is mor like ly to succeed with manipulation of the plant rather that the bacteria. Soybean and common bean mutants have been isolated which lack auto-regulatory control of nodule number and have been shown to be partially tolerant to nitrate. This has not yet proven to b of agronomic advantage, likely due to the restricted root growth of these mutants. Auto-regulartory control of nodule number has been shown to be common among several legume species, indicating the conserved nature of this genetic control. Improvement of symbiotic N2 legumes, the latter already derive a greater proportion of nitrogen from symbiotic N2 fixation.


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