It's a pretty good example of a few things.
Starting from left.
Ear 1 & 2 lack of fertility early on.
Ear 3 severe pollination issues - no fertility problems.
Ear 4 and 5 - ran out of fertility around tasseling.
Ear 6 moderate pollination issues - looks like the plant germinated late.
Ear 7 is immature
Ear 8 - tip back - either genetic or linked to planting density/light levels.
Ear 9 - on the edge with full light and adequate nutrition.