Variation in nitrogen use efficiency and root system size in temperate maize genotypes
1997
Beem, J. van | Smith, M.E.
The potential for genetic improvement in nitrogen use efficiency (NUE) depends on the magnitude and nature of differences among varieties. The objective of this study was to evaluate NUE and its relationship to root system size in temperate maize genotypes. Twelve inbreds and ten hybrids were planted under two N levels (16 and 125 kg N ha-1) during 1993. Recognizing that root parameters may provide a partial explanation for differences in NUE, root system size was estimated using a portable capacitance meter. NUE differed significantly for inbreds and hybrids under both N treatments, with NUE under low N being roughly seven times greater than NUE under high N. In addition, there were wide differences in the genotypes' root system response to low N. No association was found between NUE and root system size as measured by capacitance. Thus, an increase in root system size would not appear to be an effective strategy for increased NUE.
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