by Ken Allan

Among gardeners who like to save their own seed, hybrid has become a dirty word – and with some reason. Seed sellers promote hybrids at the expense of equivalent open-pollinated varieties because there is more money in the more expensive hybrids. Also, as breeders make improvements, they tend to release the improved varieties as hybrids, even when it would be possible to produce open-pollinated varieties with the same improvements, because a hybrid can be brought to market faster. And by keeping the hybrid’s parents secret, the breeder can maintain a monopoly over that variety and ensure that growers will return every year for more seed, rather than going to a competitor or saving their own.;

I am happy to pay a premium for hybrid seed if it offers some real advantage. But when one of my favorite hybrid varieties is dropped, I’m stuck. I can’t even produce my own hybrid seed because I have no idea what the parents are or how to obtain them. However, since researching and solving this problem, I have come to regard hybrids as a breeding opportunity rather than as an obstacle preventing me from gardening as I wish.

Some of the advantages that a hybrid can confer are increased vigor, rapid growth, higher productivity, tolerance to adverse growing conditions and resistance to disease. Hybrid vigor is most apparent with corn, onions and the brassicas. With other vegetables, there is little or no increase in vigor from hybridization. If a hybrid tomato, pepper or squash which has some advantage over other varieties is introduced, that advantage probably comes from the introduction of new blood in the breeding lines and not from the fact that it is a hybrid. In other words, when seeds are selected from that hybrid and selections made for the best plants, it is usually possible to stabilize an open-pollinated variety which is as good as (or even better than) the hybrid.

Dr. Ernest Kerr, a plant breeder, wrote in 1947: "The chief value of hybrid tomatoes will be (1) to provide a means whereby a plant breeder can control the production of seed of his introduction or (2) to introduce quickly disease resistance or some other simply inherited characteristic into a commercial variety. Standard varieties equal in quality and productivity to hybrid varieties can probably be produced but their production is a much slower process." In 1992, in the Heritage Seed Program magazine, Kerr wrote, "My thinking is the same today, but all of our work at Stokes is on producing inbreds and hybrids. There is more money in hybrids for the Seedsman."

The usual procedure in a breeding program is to find plants with superior characteristics and then to combine all of those superior characteristics in one variety by making crosses and selecting. A new hybrid is the end product of a search, sometimes world-wide, for new plant material. The search is followed by many crosses and selections until all of the desired characteristics are incorporated into one or the other of the parents of the hybrid. The important genes are all there in the hybrid, most of the footwork has already been done, and all it takes to create an equivalent open-pollinated variety is for some gardener like you or me to grow out seed from the hybrid and start selecting.

This is not to say that there are no inherent advantages to hybridization. Not only is hybrid vigor a real advantage in the case of some vegetables, it is possible to create, through hybridization, varieties which could not be created any other way. Seedless fruit can be produced by crossing species which are closely enough related for the cross to take but unlike enough that the product of the cross is sterile, just as, in the animal kingdom, the horse and donkey can cross, but the resulting mule is sterile.

When my favorite watermelon, 'Tri-X Seedless Hybrid', was withdrawn from Harris’s seed catalogue, I did some research. All standard watermelons are diploids (having a double set of chromosomes). It is possible to use colchicine to double the ploidy, creating a tetraploid watermelon. Tetraploids cross readily with diploids but the resulting triploids cannot reproduce themselves.

I got some colchicine and created a tetraploid watermelon, 'Tetra Baby', from the diploid, 'Sugar Baby'. I have produced seedless watermelon seed by crossing 'Tetra Baby' with a standard diploid watermelon, and can do so again any time I want, but I have made some interesting discoveries about 'Tetra Baby'. It has the same flavor that I especially liked in 'Tri-X'; it is semi-seedless, producing only one tenth the seeds of a standard watermelon – few enough that they are not a nuisance, but more than enough to save for next year's crop. So I now grow 'Tetra Baby' instead of one of the seedless hybrids, like 'Jack O’Hearts', which are presently available.

In this case, I discovered a superior alternative to a hybrid. The main opportunity presented by a commercial hybrid, however, is not that it forces us off the beaten path, but that it offers us a partially completed breeding program. The work that remains varies. 'Sweet 100' and 'Sweet Million' are among the easiest hybrids to stabilize, which is perhaps why a number of open-pollinated versions are available. With 'Sweet 100' and with most tomatoes, there is not a lot of variation in the second generation, so growing out ten plants and saving seed from the best for a few years should be sufficient to create a stable open-pollinated variety which is very similar to the original hybrid variety.

You should also keep an eye out for variations which are superior, in some way, to the original. In the summer of 1990, a volunteer from either 'Sweet 100' or 'Sweet Million' grew in the corn and matured some fruit before I got around to pulling it out. When I tasted one, it seemed to me that the flavor was both different from and better than its parent. When a new and distinct characteristic is discovered, it may be more difficult to stabilize than if one is just aiming to replicate the original hybrid; when I grew out 20 plants in 1991, only two had the distinct fruity flavor that I had detected in the volunteer. By 1995, after growing six to ten plants each summer, most were breeding true.

If there is a lot of variation, then the first planting may have to be large in order to find a few promising plants. In the spring of 1993, I found in a supermarket some sweet peppers that were a very attractive deep dark red, a color so vivid that one would usually find it only on custom painted cars. The peppers were large and blocky with very good flavor so I saved the seed, even though I knew that the variety was almost certainly a hybrid. I started hundreds in a flat and they were just starting to put out their first true leaves in mid-June when all my other planting was done. I had some unused space that year and put out close to two hundred seedlings. My reasoning was that any plant that produced fruit after the very late start would be worth saving.

The plants were extremely varied, confirming that they were from a hybrid pepper. About ten plants produced good green peppers and seed was saved from three of these. All three lines produced good peppers in 1994 and seed was saved from the best plants of two of these lines. These peppers have good red color when they ripen, but they are not quite in the same league as the original hybrid – this was a sacrifice that I made when I started them late that first summer, not allowing time for ripening and hence selection for color.

One technique for mass producing hybrid seed is to introduce pollen sterility into the female parent line so that it cannot self-pollinate; viable pollen must come from the male parent, ensuring hybrid seed from the female plants. The gene for sterile pollen may prevent the seed of the next generation from self-pollinating.

Some years ago, I grew the yellow hybrid storage onion 'Cuprum' ('Copra' is similar in name but is a different variety) and found it very productive and also very firm in storage. My only source was Stokes and they discontinued it in 1992. Onion seed keeps very poorly so I store my extra in the freezer and had a small quantity to grow in 1993. I kept the best of these onions through the winter and replanted them in 1994 to let them go to seed. Through good fortune, rather than any planning on my part, I also kept a few bulbs of the red onion 'Tango' which had also been discontinued.

Both varieties produced beautiful flower heads, but while 'Tango' produced lots of seed, 'Cuprum' was spotty, with only a few of the florets in each flower head actually producing seed. When the seeds from yellow 'Cuprum' were grown out this year, all but two grew into red onions! I deduced from this that the 'Cuprum' pollen was, for the most part, sterile and most, if not all, of the 'Cuprum' florets to produce seed had been pollinated by red 'Tango'. If the 'Tangos' had not been nearby, there would have been no seed on the 'Cuprums' (even if the two yellow ones came from self pollination, I might have missed them) and that would have been the end of it (I have no more hybrid 'Cuprum' seed).

What I hope to be able to do is eliminate the sterility gene and then select for yellow storage onions until I get back to something resembling the original 'Cuprum' hybrid. Since onions are known to lose vigor from inbreeding, I will have to maintain a certain amount of variation within the resulting variety. I will also be selecting for a red 'Cuprum', since this year’s red 'Cuprums' were larger and more vigorous than the 'Tangos'.