As far as the CHB Seed Library is concerned, we are happy to accept new or part used commercial packs of hybrids, however we would prefer that seeds were not returned to the library from these plants or from other commercial hybrid plants grown, due to the unstable nature of these seeds.
Many varieties of commercial seed are hybrids. This means that parent of these seeds has been cross pollinated with another selected variety (within the same species), resulting in a new “hybrid” variety (known as filial 1, or F1). This deliberate cross pollination is normally done by hand between two very genetically pure lines (highly inbred), it is the cross breeding of these pure lines that gives a very uniform result in its offspring (the F1 Hybrid).
Unfortunately when seeds are saved from the F1 hybrid, the genetic traits of the original parents and grandparents reappear and the resulting plants show a high level of genetic variation. In other words you will likely get a range of quite different plants from the same lot of saved seed. The unpredictable nature of these seeds is why many people say that you shouldn’t save the seed from hybrids…. that’s not to say you cannot grow the seeds saved from hybrids (see article about the ‘Snarky Orange Cherry’ tomato).
Natural hybrids or cross pollination can occur with open pollinated varieties and seeds saved from these unintentional crosses may be genetically unstable and display traits that are unexpected, but this is not the same as a commercial F1 or F2 hybrid.
To prevent accidental hybridisation it is important to isolate plants that are prone to cross pollination, these plants are generally considered hard or advanced in terms of seed saving for the home gardener. Some plant species are more prone to cross pollination than others, for example members of the Cucurbitaceae (pumpkin/melon/cucumber) family and members of Poaceae (grass/corn/wheat) family readily cross pollinate and this needs to be tightly controlled to save seed that is true to type.
Hybrid – when plant breeders intentionally cross-pollinate two different but specific varieties of a plant, aiming to produce an offspring, that contains the best traits of each of the parents. This new variety is an F1 hybrid. Seeds from hybrids are subject to high levels of genetic variation so do not reproduce “true to type”
Heirloom – plants are open pollinated and have been selected over generations to form a stable variety. The seeds from these varieties reproduce “true to type”. Heirloom seeds still have a small amount of natural variation in them and can in some instances naturally cross pollinate creating a natural hybrid.
Heritage – This has mixed definitions but is often used interchangeably with heirloom. Heritage implies that the variety has an origin pre 1945, as that is when commercial hybrids became commonplace.
GMO – Genetically Modified Organisms are the result of genetic engineering. This is a process during which the plant’s DNA is altered by including genes from other non related species or rearranging or deleting the existing genes. To date, no fresh produce (seeds, fruit, vegetables, meat or milk) originating in New Zealand is genetically modified, some processed foods do contain GMO’s.
N.B There have been recent studies that have found a select few naturally occurring instances where plant DNA carries DNA from another organism, the most common of these transgenic plants is kumera (article here).
Interesting links and further reading
- Article about growing seed saved from a hybrid ‘sungold’ tomato, resulting in a new variety ‘Snarky Orange Cherry‘
- Article on naturally occurring transgenic mutation in sweet potatoes, from Science Daily (original source Ghent University)
- An easy to understand, but slightly more technical, article from Backyard Gardener on “hybrid vs heirloom seeds“
- Article from The Science of Gardening, has a good section on hybrids and GMO’s – Three ways to make a new plant