Cross pollinators: F1 hybrids
The issues surrounding emasculation for self-pollinators also apply to cross-pollinators. But the difficulties are commonly less severe, because these plants have evolved mechanisms to ensure cross-pollination. These include:
- Dioecious plants (separate male and female plants; examples: date palm; papaya, yam)
- Diclinous plants (separate male and female flowers on one plant; examples: maize, zucchini)
- Self incompatible plants (examples: clover, pear)
- Dichogamous plants (where the stigma is unreceptive when the pollen is released; examples: pecan, caraway)