[rms]

I'm sure there is room for incremental improvement, but we've certainly reached the point of diminishing returns.

I briefly searched and can't find sources, but I believe the wheat of 1900 used around 12% of its energy to make food and the rest to sustain its own structure. Now it's something like 90% of the energy the wheat receives goes towards making food.

[rfreytag]

Good points but you could still engineer the plants to: grow in saline conditions (I think that is being pursued), over wider range, to resist drought or flood better, defeat pests and blights (rust was mentioned in the article), and come back from being downed by weather. The goal being to more frequently achieve maximal yield by increasing the range and durability of the crop.

The last bit would be to eliminate the need to sow the crop by having wheat be a perennial. That would greatly reduce the energy input to the crop.

Plenty more to do.