Phenotypic assessment of commercial wheat (Triticum aestivum) crosses with a synthetic hexaploid incorporating wild germplasm from Aegilops tauschii

Abstract

The wheat crop in the United States, and indeed globally, has shown high levels of genetic uniformity. A lack in genetic variation is causing dramatic fluctuations in total wheat crop yields in response to environmental conditions and has created serious production risks. This study was undertaken as a step to address this issue with an aim of develop a new high-performing line incorporating wild wheat germplasm for the Colorado State University breeding program. The purpose of using wild germplasm is to provide a source of genetic variation not currently present in the US wheat crop. This study grew 72 different crosses with eight controls and included two reps each for both an irrigated and unirrigated treatment. Traits that were assessed included grain yield, harvest index (HI), heading date, plant height, lodging and other physical features that were assessed visually. The results showed that one first generation cross (HRS2015-378) clearly stood out above all other lines, including the commercial cultivar controls. HRS2015-378 was ranked first in both treatments for HI along with third and fifth for grain yield in the dry and wet treatments respectively. The values for HI of this line were 0.34 and 0.52 with grain weights from 1m biomass strips of 118 and 150g for the dry and wet treatments, respectively. This cross along with three others, two of which were also first generation crosses and one a second generation cross, were selected for the Colorado State University breeding program for their consistently high performance compared to the commercial controls in all traits measured across both treatments. In the coming years these crosses will undergo more selective and intense breeding across multiple locations with the expectation that at least one will eventually be released as a new commercial variety.