This study evaluated over 150 wheat x wheatgrass derivatives in a series of field experiments. The objective was to assess their capacity to regrow post-harvest and yield grain over successive years, and thereby identify characteristics common to the surviving breeding lines. Over the 3-year experimental period 61% of the 176 experimental entries demonstrated some capacity for post-harvest regrowth. Of 125 entries planted in the first two years of experimentation, 34% persisted to produce a second grain harvest in year 2. Three entries from 73 planted in 2008 persisted to produce grain in 3 successive years. In a subset of 87 entries that underwent cytogenetic analysis there was an association between regrowth ability and the presence of at least one whole genome equivalent (14 chromosomes) from the perennial donor species. If the wheat parent was a hexaploid (2n = 42), an entry required at least 56 chromosomes to achieve any substantial post-harvest regrowth. However, the presence of 56 chromosomes was no guarantee of a capacity to survive post-harvest. The morphology of the hybrid germplasm was highly variable for every trait assessed including grain yield, grain size, grain quality, harvest index, tiller height and head morphology; reflective of the diversity of pedigrees. Narrower kernels appeared to be associated with higher grain protein concentrations. Unextractable polymeric protein (UPP) correlates with rheological properties of the doughs; some of the experimental entries had very low UPP; the majority had high UPP suggesting useful flour, dough and baking properties. A high level of disease resistance was observed in the subset of entries tested for leaf, stem and stripe rust as well as wheat streak mosaic virus, indicating that further development of hybrid germplasm would be unlikely to pose an unacceptable disease threat to conventional cereal crops, particularly where amphiploids were deployed. The variability of the cohort and the presence of entries with desirable agronomic and grain quality attributes suggested a potential to breed and select for perennial wheat derivatives with commercially desirable characteristics. (C) 2012 Elsevier B.V. All rights reserved.