Genetic Improvement Of Nitrogen Use Efficiency In Spring Barley.

The development and use of N efficient cultivars, together with improved nutrient management strategies, may reduce fertilizer input costs and the negative impact of excessive N on the environment.  Our research group at the Field Crop Development Centre, Alberta Agriculture and Rural Development, has been working on genetic improvement of barley nitrogen use efficiency (NUE) since 2007.  As part of this effort in 2009, 700 barley germplasm lines were assembled from local and exotic sources and screened for NUE under field conditions.  From these, twenty-five genotypes including checks were selected and evaluated under low and high N conditions during the 2010 and 2011 seasons.  Data were collected on grain yield, NUE (kg grain yield kg^-1available N ha^-1) and total N recovery in the grain or grain N yield (kg N ha^-1).  The results showed that Vivar had the highest NUE at 59 kgkg^-1ha^-1 compared to the least check F09438 at 31 kgkg^-1ha^-1.  The high efficiency of Vivar was primarily attributed to its intrinsic ability to maintain yield potential under reduced N conditions.  Other lines including I09501, I09502 and I08128 were also good in NUE at 54 kg kg^-1ha^-1.  However, the latter three genotypes displayed different efficiency characteristics of a much greater yield response than Vivar to the high N regime.  The most efficient lines recovered 164-169 kg N ha^-1 in the grain, averaged over the two years and across the low and high fertility regimes, compared to 147 kg N ha^-1 for the popular feed barley variety Xena or just 100 kg N ha^-1 for F09438.  These efficient materials are being utilized in the crossing program to combine the different NUE attributes and develop superior cultivars that yield well across low and high N regimes.