Saturday, February 4, 2023
Feb. 4, 2023

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Gardening with Allen: New flowers develop over years


Could you explain the difference in how new varieties are developed when some are available from seed and some are only available from plants?

The development of new flower varieties is a fascinating process. I worked for 10 years for a seed company that developed F-1 (first generation hybrid flowers and vegetables) that were sold as seed.

The process starts by observing and selecting individual plants which have qualities that set them apart as being unique or improved in some way.

The second step is to self-pollinate and select for the desirable qualities for three or more generations. The self-pollination process creates offspring which are very uniform in appearance. This process can be speeded up by doing more than one generation per year in greenhouses.

The third step is to cross pollinate several of these plant families with each other and then observe and select the cross or crosses which are the most outstanding. Before naming and introducing a new variety, test production is done on a trial basis to make sure seed can be produced efficiently in quantity.

The fourth step is naming and offering the new variety for sale. You can see that this breeding process can take three or more years. And that does not include the time and effort spent in marketing and advertising.

Seed is produced under carefully controlled conditions, which often includes hand emasculation and pollination to prevent any self-pollination or stray cross-pollination. Because the breeder has exclusive access to the parent families, no competitor can produce it. Seed from the hybrid is very variable, ranging from the extreme of one parent to the extreme of the other parent and everything in between.

Greenhouse growers buy most of the of F-1 hybrid seed produced by seed companies. They plant the seed and grow plants that are sold to stores where they are available for purchase by gardeners. Gardeners can also purchase seeds from seed companies and grow their own plants.

Nowadays, most flower varieties are produced by a shorter process that does not include seed production. This process has been made feasible by the development of the tissue-culture propagation method. With this method, new plants can be produced from a single cell division from a callus of plant tissue grown in agar media.

In this alternate process the first step, selecting outstanding individual plants, is the same as the F-1 process, but then horticulturists skip right to the third step and make crosses between the selected plants.

The seed from these crosses is quite variable. Seed is planted for observation. Outstanding individual plants are then selected and named so production can begin immediately using tissue culture propagation.

Small plants grown from the tissue culture process are sold to greenhouse growers who grow and sell them just like those grown from seed. Gardeners are unaware of which were produced from seed and which were produced by tissue culture.

Three of the new All-America Selections award-winning flowers were produced using the F-1 hybrid method and three from the alternate method. All five of the AAS award-winning vegetables were created using the F-1 hybrid method.