1.   Corn plants are entering the crucial growing phase, where pollen fertilizes the kernel, allowing it to grow.

2.   So even if an occasional ovule is in working order, it is usually never gets fertilized by pollen.

3.   The pollen no longer fertilizes the flowers, and they drop off, victims of unrequited love.

4.   Bullock said a more pervasive cause is cross-pollination, when pollen from one type of corn fertilizes another type, giving both the same characteristics.