Heirlooms, Hybrids and GMOs

The definition of an heirloom plant is embroiled in dispute, but generally it is considered to be a plant which pre-dates 1945, the end of World War II being the beginning of the increase in the number and availability of commercial hybrids to farmers and gardeners. Some heirlooms are centuries old, and some date from the turn of the last century.  While almost all heirlooms are also hybrids, they produce viable seed through open pollination that will produce plants true to the parent. This allows the gardener or farmer to save seed from one year to the next with the assurance that the plants he grows will be the same as the plants he grew the year before. Corn is an example of a vegetable that has many heirloom varieties all of which are hybrids.  Corn began as a cross between the two grasses teocinte and gama grass probably in the Tehuacan valley of Mexico.  Recent genetic research has found that the change from the two grasses to corn with ears as we know it probably took place over the very short time of only a century. Corn cobs that have been carbon dated were found to be 5600 years old.  This points out the fact that man has been breeding crops to fit his needs for a very long time.

Bringing us to hybrids.  A hybrid is a plant whose parents have different characteristics from each other and have been cross pollinated.  The plant resulting from seed thus engendered will have characteristics of both parents, but be a different plant than either of the preceding generation.   Let’s use a pansy as an example.  I grow Imperial Antique Shades Pansies, a Viola wittrockiana hybrid that produces several different colors in the yellow/buff through pink/magenta range.  I also grow Viola tricolor, aka johnny-jump-ups or heartsease with their little tri-color faces of white, yellow and blue.  When these two grow next to each other, they share pollen and the resulting seed grows a plant that is like neither of the parents.  It has a medium sized flower, where the Antique Shades have a larger flower and the little heartsease have a very small flower.  The new plants are in the same size range as the parents, both of which will spread, but the leaves on the new plants are a bit larger than either parent.  The flower color is always purple.  When these plants share pollen, their offspring are slightly different in color than the preceding generation, though when I have isolated one of these, they have produced seed that was true to the hybrid parent.

pansies with heartsease parent	pansy hybrid

F1 hybrids are very specifically bred hybrids involving careful selection and hand pollination.  Two plants are chosen for desirable traits; for instance, the flower color of one and the habit of the other.  Each plant is then hand pollinated to itself and in isolation through several generations until the resulting plants have the desired trait and are reliably reproduced.  This is then a ‘pure’ strain.  Two pure strains are then bred to each other. The resulting offspring will have the desirable traits from both parents, making it a better plant in some ways. The drawback is that when openly pollinated, this plant will not necessarily breed true. While this is done to make some produce more user friendly for commercial growers, it is also done for home gardeners to develop both flowers and vegetables with unusual colors and enhanced flavors.

GMOs are organisms whose genome has been altered by geneticists by splicing in DNA molecules from other organisms, not necessarily of the same species.  This alters the genes for a specific effect such as resistance to herbicides, for instance. One well known example would be carrot genes spliced into the rice genome to increase its nutritional value.  Another is, of course, Round-Up ready corn and soybeans which have been made resistant to the killing power of the herbicide Round-Up.   There are instances where this technology has been very useful in medical applications.  There are instances in which it has been frivolous, as in making tropical fish that glow in the dark for sale to aquarium hobbyists.   In the plant world, GMOs have been thrust upon us with little thought to potential damage through cross pollination with non-GMO crops.  This has led to fears about the destruction of viable unadulterated seed.  Personally, I find GMOs disturbing. Their general use has been pushed beyond the testing done on them and the consequences are being discovered as afterthoughts.  This is, of course, purely editorial opinion.

To growers of all sizes, it is beneficial to be familiar with these different categories.  If you are planning on raising plants and saving seed regularly, you will do well to plant heirloom varieties.  If you desire a specific color or shape or taste, f1 hybrids will often provide you with exactly what you want.  If you are looking for herbicide resistant plants, then you will do well with GMOs.