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MANUAL FERTILIZATION AND CHANCE CROSSING - Part 2 |
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The stem of each seed-pod should be labelled with a tag of some material that will retain legible markings for at least several months. Thin zinc labels are excellent. The writing should be in pencil; wetting will always make them easier to read. Each label should give the names of both parents, and indicate which gave the pollen and which the seed.
When fertilization has occurred the seed-pod will begin to increase in size within a few weeks. When it has failed the hip will slowly shrivel, die and fall. Pods take from four to eight months to ripen, by which time most of them are at least partly red or yellow. It is best to leave them ungathered from the plants until their stems commence to shrivel. This is all irrespective of whether the pollination has been done by Nature or by hand. "after-ripening" In the past, hybridists at this stage opened the hips with a sharp knife, removed the seeds, which varied in colour from cream to brown, and then planted them. Only about five per cent of the seeds germinated. More recently, seeds have been submitted to a process of "after-ripening" before sowing. This consists of keeping ripe rose-seed at a temperature of about 41 degrees Fahrenheit in moist conditions for a time. Neither 32 nor 50 degrees Fahrenheit will after-ripen seed although fluctuations between those temperatures are effective, especially if the average is about 41 degrees Fahrenheit. This is what commonly happens in Nature, in cool climates. The seed can be kept in moist sand, but ripens much faster in granulated peat. Late July is the best time for after-ripening and seed-sowing. The seeds are removed from the hip as usual and are dropped into a cup of water. Those that sink are usually fertile; those that float are usually infertile. Granulated peat is superior to sand for after-ripening, because it gives an easy and regular supply of moisture and air. It is naturally highly acid. It can he neutralized with lime or leached with water until nearly neutral. Unneutralized peat often injures rose rootlets if they become too long before being transplanted to soil. It is unfortunate that some seeds germinate as well as after-ripen at 41 degrees Fahrenheit. By using this method it is said to be possible to get nearly one hundred per cent germination of seed when good female parents are used. Such results were formerly quite impossible, but it means too much trouble and expense for most amateurs. It well repays the hybridist who is doing a large amount of work. We can crudely, but fairly closely, imitate the after-ripening procedure in our gardens by removing the hips and burying them in the beds or in boxes of light soil. They must be kept wet and buried until the outer case of the hip commences rotting. The seeds are then removed from the pods. This will give a much higher percentage of germination than the five per cent obtained by the old method. Cool garden positions will be best for the seeds. From this stage all seeds are treated in the same manner, irrespective of which of the three methods has been employed. If the old method is followed the seeds will be hard. The floating test could be used to decrease the percentage of failures to germinate. Tips of small roots will often be visible on after-ripened seed. It is discouraging when seeds, which are apparently viable, fail to germinate, or die soon after shooting. A large percentage will grow if well selected, even crudely after-ripened, and given good conditions with sufficient time. |
