abc logo What is a hybrid?
Rhododendron ABC's #2

In the first article we discussed the meaning of the word species and learned that the off-spring of two individuals of the same species are similar in their main traits to the parents and to each other. The results of the crossing of two individuals of separate species are quite different and the off-spring will generally show traits that are intermediate between those of the parents. These off-spring, then, are known as hybrids.

For the many animals and plants, the hybrids resulting from the mating of two species, while having intermediate traits, often show more vigor and stamina than the parents. They are, however so far as further breeding goes, "end of the liners". They are mostly sterile and do not have the ability to act as parents to produce off-spring. Probably the best known example of this is the mating of a horse with a donkey. The result, known as a mule, is a creature whose appearance is reminiscent of both a horse and a donkey, but which is tough, canny and vigorous. It is, however, sterile and cannot produce off-spring. (There have been a few reports of exceptions to this rule but such occurrences are very rare).

Strictly speaking, a hybrid is the cross of two species and the results are the F1 generation. To obtain much more variation, further crosses between individuals of the F1 generation can be made to produce an F2 generation and on through F3 , F4 , etc. generations. To add further complexity, hybrids can also be crossed with species. Thus, with rhododendrons, all possible hybrid combinations are seemingly possible.

There is some limit to this, however. Even with rhododendrons, to obtain satisfactory results, fertile off- the species used cannot be too widely variant in traits. It is much more difficult to cross, say, a lepidote species with an elepidote species or either of the species with an azalea species (we will discuss lepidotes and elepidotes in a later edition). It is, nevertheless, not impossible and attempts to make such crosses go on all the time, but with very limited results.

One other thing to keep in mind if one wishes to join the ranks of rhododendron hybridizers, is that it is important to choose which plant is to be the female or seed parent and which is to be the male or pollen parent. To illustrate this, remember that the useful mule is a hybrid between a female horse and a male donkey. The result of crossing a female donkey and a male horse is a much inferior creature called a hinny! If (and I believe it to be so) the same thing holds true for rhododendrons, the correct choice of which plants to use for seed and pollen parents can have a real effect on the nature of the hybrids from the hybridizations process.

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Dave Goheen