Perennials are such an intuitively appealing idea but a plant expends a lot of energy ensuring it can make it through the fallow/winter season successfully. Thus perennial cereals only make sense where the cost of seed and planting exceeds the impact on yield. My understanding is even at the theoretical minimum energy needed for most cereals in most growing regions to have a 90% chance of surviving perennially you need a huge cash subsidy for lost grain yield or for seed and planting costs to rise many-fold. More likely to work in rice than wheat/kernza but never likely to work at all unless we as a species change how we think of the objectives of agriculture. Happy to be proven wrong though.