02354naa a2200265 a 450000100080000000500110000800800410001910000220006024501910008226000090027352015470028265000100182965000220183965000230186165000120188465000290189665000130192565000140193865000160195265000160196865000230198465300240200770000170203177300400204816106281995-06-27       1989    bl uuuu     u00u1 u    #d1 aPEREIRA, P. A. A.  aSelection of common bean (Phaseolus vulgaris L.) for N2 fixation at different levels of available phosphorus under field and environmentally-controlled conditions.h[electronic resource]  c1989  aPhosphorus is one of several factors which affect N2 fixation and along with N, is a principal yield-limiting nutrient in many regions of the world. Since the legume plant is an essential partner in symbiotic N 2 fixation, knowledge of host genotype variability for this process at different levels of P availability will be useful when breeding bean cultivars for enhanced N2 fixation. The objective of this study was to obtain common bean (Phaseolus vulgaris L.) lines able with enhanced ability to support biological N 2 fixation under different levels of available phosphorus. Experiments were conducted in a growth room using a sand-alumina system to provide different levels of available P and in the field on a low-N soil. In the growth room studies, P availability strongly affected plant growth and traits related to N2 fixation. No significant interaction was detected for P levels x bean lines, indicating that bean lines performed similarly at both high and low P levels. Total shoot N was used as a direct and indirect measure of NE-fixation potential under growth room (N-free media) and field (low-N soil) conditions, respectively. Based on this criterion, two of the 41 and 54 inbred backcross lines of a segregating population evaluated in the growth room and the field, respectively, contained greater shoot N content than the recurrent parent and N shoot contents similar to the donor parent. Variability of N 2 fixation under low available P was observed, and high N 2 fixing and high yielding progeny lines were detected.  aBeans  aNitrogen fixation  aSelection criteria  aFeijão  aFixação de Nitrogênio  aFósforo  aGenética  aNitrogênio  aNodulação  aPhaseolus Vulgaris  aAmbiente Controlado1 aBLISS, F. A.  tPlant Soilgv. 115, p. 75-82, 1989.