Evaluation of Near Isogenic Lines for Grain Protein Content in Barley

Challenged by global climate change, plant breeders must implement new methods for gene discovery and deployment to improve traits anticipated to be impacted. In barley (Hordeum vulgare), nitrogen use efficiency (NUE) is one such trait. We evaluated NUE-related traits in a set of near isogenic lines (NILs) and varieties under nitrogen-limiting and non-limiting treatments. The NILs were created with the recurrent parent Lacey and donor parents Karl and Chevron contributing low and high grain protein concentration (GPC) alleles, respectively, of a gene presumed to be barley’s ortholog of the Gpc-B1 gene from wheat. The varieties Robust, Tradition, Lacey, and the high and low GPC NILs were grown in Crookston, MN in 2011 and 2012 with six replications in a randomized complete block design. The objective of this study was to determine the effect of the Gpc-B1 gene on traits related to NUE. Nitrogen level was consistently significant for predicting yield, spikes per area, seeds per spike, and plant height. Genotype was consistently significant for the same traits plus maturity. Generally, the interaction between nitrogen level and genotype was not significant, and the percent difference for yield between nitrogen levels was not significant among different lines. The high GPC NIL was lower in yield and spikes per area compared to Lacey while the low GPC NIL was not significantly different from Lacey for any of these traits. Similar to results in wheat, our preliminary results show that the high GPC allele correlates with low yield.