I have been talking with my farmer friend and we talked about seeds and pollination in general. Cross pollination is a threat with corn planted in and around where cattle corn and other hybridized corns are planted. to safeguard against this use paper bags over the corn cobs once they start to send out their silk, then once the silks are full out, untie the bottom of the bag, and take the bag to another corn plant and cover the cob on that plant. give the bag a good shake to stir up the pollen and you have just artificially pollinated your corn cob with the correct pollen for its breed.
Offered by Gus.
Mother Earth News, Sep/Oct 78
The flowers of most garden vegetables are just too small and/or they produce too few seeds to make hand-pollination practical. In such cases caging - which is just what the name implies - offers a sure-fire way to achieve the isolation and control you're after. (Just be sure to include at least five plants of the same type in each cage to encourage vigorous cross-fertilization.) As shown in the illustration which accompanies this article you can easily construct cages from materials found around the house ... but different types of screening must be used depending on whether the enclosed plants are pollinated by the wind or insects.
Cages for wind-pollinated plants should be covered with muslin or cheesecloth to exclude the extremely fine pollens characteristic of these types. (Spinach pollen is so microscopic however that you might as well forget caging altogether and just take your chances that no one nearby is growing another variety-for seed.) In order to make sure the pollen is well distributed within your cages give the enclosures and/or the plants inside a few shakes every two or three days.
When caging vegetables that are pollinated by insects your mesh need only be fine enough to keep the critters out. Window screen is excellent for this purpose. Remember though - in order to ensure pollination it will be necessary to place insects inside the enclosures. Honeybees are ideal for this purpose of course but for obvious reasons they're hard to handle. And if kept away from their hive they soon die. Flies however offer a good alternative and you can breed your own by setting out a pan of raw meat or innards. The flies will lay their eggs in the rotting flesh ... and when maggots appear you can just place the container of infested material inside your cages. The maggots will soon metamorphose into adult insects which will then pollinate the fruits or vegetables.