SEED POLLINATION CAGE
The reason for the net is to isolate the bees so that no foreign pollen is introduced into the process of cross pollinating the parent plant varieties to create the new hybrid variety. Without the net, a distance of 3 miles would be required to ensure isolation. In order to obtain a pure cross, this 3 mile circle would be required to be totally free of any plants of the variety being cross pollinated. Another plot of the same variety over 3 miles away is generally sufficient to keep the bees from transferring pollen between them.
With about 400 caged plots at this 100 acre facility, a distance of 1200 miles would be required to obtain the equivalent isolation without the cages.
Support for the mesh net is provided by metal upright frames that continue across the top of the cage. The entrance zipper can be seen to the left side of the picture (Fig. 1). The temperature inside the cage is about 8° cooler than the ambient air for the darker colored (green) nets and about 1° warmer for the lighter (white) net material.

SINGLE PLANT CAGES

New carrot parent lines are developed by producing seed from single plants containing the desired characteristics of size, shape, color disease resistance and flavor.

Common house flies are used to pollinate these single plant cages because they are too small for bees.

CONTINUED SELECTION
After the new hybrid has been evaluated in the real world of the grower field trial and passed, some are selected to advance to the next level which is a full field trial of several acres. Seed for this trial is produced again from the original parent stock in a larger isolation cage (Figs. 4&5) to obtain the required quantity. Of the remaining 20% of the hybrids that make it to this stage, another 80% are eliminated in this second grower field trial. In fact, out of the original 100 hybrid crosses, only one or two of the varieties end up being clearly superior to existing varieties and go on to become a standard in the industry.
Once the new hybrid passes the second grower field evaluation, the varieties has outgrown the seed cage and is handed off to the production department for large scale seed production in an open field with the required 3 mile isolation.

The development process for a better hybrid seed can span many years from the time the first parents are crossed until it has completed all the trials and the seed is available to growers for vegetable production. Typically, each step in the process has to wait a year until the next growing season rolls around.

The life of a hybrid seed is broken down into "phases" starting with breeding and development which is phase zero. It progresses to phase 1 in the grower trials and eventually to phase 3 when the seed is sold for varieties that make it. The final phase is 4 - the grave yard for the has been's. A successful variety can have a life of 15 years or more from start to finish. Hybrid seed development began in the 1950's and shows no signs of going away any time soon.

As long as there's bees to pollinate the bloom, better plant varieties will continue to be developed.