These shots are of 2 different hybrids.The hybrid to the left is at a low plant stand of 21,000 per acre.As you can see it is tillering profusely.The hybrid above has a final plant stand of 29,000 and is still tillering to some degree.Tillers are nothing more than a sign that the hybrid has plenty of light and good enough growing conditions that it wants to initiate more vegetative growth to absorb more sunlight.Research studies have shown that when radiactive Carbon is absorbed by a tiller that same radioactive carbon can be found in the grain of that hybrid at harvest.So tillers are not necessarily bad, they are more of an indicator that your plant stand is perhaps not high enough for optimal yields.