Accumulation and Translocation of Nitrogen in Spring Cereal Cultivars Differing in Nitrogen Use Efficiency

Abstract

Since northern European agricultural practices are likely to go toward systems with lower inputs of N fertilizers, it is desirable to develop cultivars with increased yield potential associated with higher nitrogen use efficiency (NUE). This study determined the extent of variation in NUE‐related parameters, specifying the primary traits contributing to the difference in nitrogen remobilization efficiency (NRE) on four spring cereal crops, two‐ and six‐row barley (Hordeum vulgare L.), oat (Avena sativa L.), and wheat (Triticum aestivum L.). Field experiments were conducted in Finland during 2001, 2002, and 2003 under two N regimes (0 and 90 kg N ha−1). Wheat had relatively high N content at maturity even though NUE was low, whereas oat and barley had higher NUE. A comparison of nitrogen harvest index (NHI) and NRE revealed that both were low for wheat, linking this with high N uptake after anthesis, suggesting that in wheat the proportion of the assimilated N used immediately in the developing grain is greater than in barley and oat. There was no strong N translocation from vegetative parts of the main shoots in wheat, which exhibited higher competition for N between vegetative and reproductive organs. Plant breeders could use these findings to their advantage in breeding spring cereal crops that not only produce high yield but also efficiently use available N in northern growing conditions.