It looks interesting, but I have not tried it. Don't know if the following link is generally accessible:
https://dl.sciencesocieties.org/publications/aj/pdfs/104/6/1716
If not, the abstract is below....this being just one study to date comparing a perennial and annual wheat.
ABSTRACT
Perennial wheat (Triticum aestivum L. × Th inopyrum spp.) and perennial rye (Secale cereale L. × S. montanum) are novel hybrid
species under development as alternatives to annual cereal crops. We conducted a 2-yr fi eld study with a split plot design to evaluate
agronomic performance, including yield, phenology, and biomass production, of perennial accessions of wheat and rye, along with
annual analogs. This is one of the first studies to rigorously compare agronomic performance of 2-yr-old plants to 1-yr-old plants
in perennial cereals. Perennial wheat produced 1.0 to 1.6 Mg ha–1 grain yield, 50% of annual wheat (2.7 Mg ha–1), while perennial
rye produced 1.3 Mg ha–1, 73% of annual rye (1.8 Mg ha–1). Modest yields from perennials relative to annuals reflected lower
harvest index, lower yield per tiller, and less kernel mass. One-year-old and 2-yr-old perennial plants had similar seed yields, yield
components, and biomass production, indicating that plant age had little eff ect on these parameters and older plants maintained
yield potential. In contrast, phenology did vary with plant age, and showed a shift toward earlier spring growth and later flowering
dates in older perennial plants. Th is illustrates an expanded vegetative period for regrowing plants of these perennial cereals. Th ere
appears to be potential for producing an early season forage crop from these cereals, although biomass yields were not high at this
site and regrowth was not always reliable. Overall, performance of perennial rye was consistent with a viable new cereal crop. On the
other hand, perennial wheat requires further selection for allocation of biomass to grain and vigorous regrowth.