Pollination is the transfer of pollen to the stigmatic surface of the female part of the flower. Flowers may be self or cross-pollinated.
Self-pollinated flowers use the pollen from the same parent plant (flower) to pollinate its own flowers.
Cross-pollinated flowers require pollen from a different plant in order to set seeds.
Commercial growers and seed producers use bee hives to make sure there are enough bees working their fields to get sufficient seed set and improve crop yields.
Bee hives can be rented from apiary specialists. Hives are moved from field to field when pollination becomes important for a crop.
Although pollination occurs naturally in plants, plant breeders use controlled pollinations to create hybrids.
Inbred parents used to create the hybrid need to be isolated so that pollen from undesirable plants can not reach the seed parents.
For some horticultural crops, this is accomplished by using isolation tents that only contain the appropriate parents for the hybrid.
Onions caged for seed production.
Controlled insect-pollinated hybrids are possible when the female or seed parent is male sterile. This means that the seed parent flower does not produce viable pollen. Therefore, pollen from the male inbred is required to create a fertile cross.
Notice how the male pollen parent produces long filaments that contain functional anthers (arrow), while the female flower lacks these structures.
Male sterile lines have been developed to act as female parents. This saves time for the hybridizer because they do not have to emasculate female flowers prior to pollination.
In some cases, hybrids must be made by costly and time consuming hand pollinations. This procedure requires collection of pollen from the male parent and transfer of the pollen to the female parent that has had the male parts removed from the flower before self-pollination can occur.
Because this is costly, most hybrids requiring hand pollinations are made in countries with inexpensive labor costs.
Flowers from the female parent must be emasculated before being pollinated.
The pollen was previously collected from the pollen parent and is kept refrigerated for a short time until it was needed.
