Breeding Orchids

The possibilities are tempting, but frequent failures and high mortality of seeds may make the whole experience discouraging and expensive. Diligence, meticulousness, and, above all, patience are the qualities required of the experimenter.

When breeding orchids, the primary obstacle arises from the fact that the orchid seed, unlike most other seeds, contains no stored nourishment and, furthermore, has no means of converting outside food to its use.

The grower is forced to find a means of compensating for this deficiency. Under natural conditions orchid seeds grow at the base of the parent plant or in the immediate vicinity.

Early experimenters, attempting to propagate orchids in an artificial environment, had success only when they planted the seeds at the base of an adult plant, where, in a way mysterious at the time, the seeds germinated and grew, although pests and fungi took an exceptionally heavy toll.

A second obstacle to the growing of orchids from seed is the fact that the conditions most conducive to the germination and growth of orchid seed—a warm, moist, rather close atmosphere-are also those most favorable for harmful fungi.

Absolute and antiseptic cleanliness will cut down the mortality in growing seed. The attainment of this antisepsis may be difficult for the average amateur unless he is a scientist or doctor.

Perhaps the most discouraging factor to the amateur is that the time required for the maturation of seedlings and the eventual production of bloom is exceedingly long. It takes from nine months to a year (sometimes longer) for Cattleya seed to mature in the pod. Five to seven years are required from seed to bloom.

When time comes to breed orchid, some orchids take less time; others take more. Phalaenopsis are said to have bloomed in eighteen months.

Some Vandas, although precise information is lacking, are supposed to take from twelve to eighteen years. Many experiments trying to reduce this long maturation period are under way, but no conclusive results have been announced.

Experiments in the field of nutrient culture give hope, however, that a method for shortening the period will be discovered.

Having well in mind the purpose of crossing, and the parent plants for this purpose selected, the grower must settle the matter of proper procedure. Both parent flowers should have been on the plant long enough to be well matured, although the flower on the pod parent may mature further after crossing.

If the pollen flower has not matured, the crossing will be sterile. Many growers make the mistake of thinking that aseptic methods need begin only with the planting of the seed.

Precautions should begin at the very beginning, with the parent flowers, for contamination may occur at the time the pollen is collected.

A sharpened stick or toothpick is sometimes used to remove ripe pollen from the male flower and place it in the stigmatic cavity of the female. If the pollen is touched by the hand, unfriendly fungi may very likely be introduced.

The preferred method of collecting pollen is to use a sharpened glass rod or a platinum wire that can be quickly sterilized and cooled. It is better to use pollen immediately, but when expedient it can be saved for a flower blooming at a later date.

When it comes to breeding orchids, the pollen may be placed first on a piece of clean white paper and then in a sterile vial or plastic capsule, which may be kept in the electric refrigerator for some months.

The vial should be corked but not too tightly sealed, to prevent condensation and the entrance of fungus. Some hydra ting agent, such as calcium chloride, may be used in the container. The pollen should be suspended over, not touching, the crystals.

After pollination the plant should be dried out a bit and removed to a more sheltered part of the greenhouse. If the pollinated flower begins to droop and the petals curl protectively over the vital organs, fertilization has probably taken place—although sometimes wilting results from a disturbance of the stigmatic cavity.

If fertilization has taken place, the ovary (behind and slightly below the flower) will begin to swell. The wilted petals will probably continue to dry and eventually drop off. If the petals become wet, however, they may rot and should be trimmed off.

The seed-bearing plant should be treated moderately, but with particular care in watering to avoid chilling at night. If the plant is healthy and well established, with good root growth in fresh medium, it should survive the ordeal.

The drain of strength on the pod-bearing plant may be obviated by supplementary feedings of a very weak well-rotted manure solution or one of the chemical formulas. There seems to be a phosphorus deficiency at this time.

Any supplementary feeding should be done cautiously; some experienced growers advocate that it be done not more than once a month.

Cattleya seed takes from nine months to a year or longer to mature. Experience shows that the longer the pod takes to mature the more virile and fertile the seed. Maturation of the pod before nine months usually indicates infertile or poor seed.

As the fruit or seed pod approaches maturation it becomes yellow and dry in appearance, the ribs begin to stretch at the seams, and, when fully dry, the pod bursts and the seeds are ejected.

The grower should watch these signs and, at the proper time, tie a paper bag—not wax, which may cause condensation—lightly over the pod to catch the seed and protect it from contamination.

Fertility of the seed may be determined microscopically, although there are other means of determination. Fertile seed, under the microscope, appears browner than infertile seed and reveals dark blurs. Fertile seeds will also separate while the infertile ones cling together in a cottony mass.

It is best to plant seed immediately, although it is possible to keep it under refrigeration, in the same manner as pollen, for a more convenient planting time.

Cattleya seed has been reported to have been stored in this way for two or three years. A shorter period is probably more safe for other orchids. Absolute cleanliness should be the rule in planting. Hands and tools should be washed in a 20 per cent Clorox solution.

If possible, seed should also be sterilized, as contamination is invariably easier to prevent than to cure.

Seed may be sterilized with a fair degree of success in 3 per cent solution of hydrogen peroxide. A much stronger solution (30 per cent) has been used without damage to seed, but this is too tricky for the layman's use.

Most growers prefer calcium hypochlorite, 10 gm. to 140 cc. of distilled water, filtered.

Seed may be exposed to this solution for fifteen to twenty minutes without harm, but a longer exposure will yellow the seed. Rapid whirling or shaking of the container holding seeds and sterilizing agent will make certain that the solution washes over each seed. Several new sterilizing procedures have recently been suggested.

Walter Carter of Hawaii, writing in the Brazilian journal Orquidea, reports success in sterilizing seed by wetting with Valsol OT (1-1000) and then using 1-2500 bichloride of mercury in the vial. K. L. McAlpine, in Orchid Review, recommends adding 1.0 cc. of hydrogen peroxide C.P. 30 per cent to 1000 cc. to the adjusted medium prepared for planting. After this is thoroughly mixed no further precautions seem necessary.

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