Stratification of seeds
In a figurative expression, I.V.Michurina - "the stock is the foundation of the turf".An important role of rootstocks is expressed in their influence on winter hardiness, growth sistem, longevity and productivity of trees( Table).
Effect of rootstocks on the growth of apple trees
| Type of rootstock | Height of trees, m | Planting density, pcs / 100 m2 | Maximum yield per tree, kg | Root winter hardiness | Tree anchor | Permissible groundwater table, m |
| Seed | 3-4,5 | 2-4 | 100-150 | Good | Good | 3-4 |
| Vegetative-propagated( cloned) | 2-2,5 | 10-20 | 40-70 | Satisfactory | Satisfactory | 1-2 |
As seedrootstocks for apple tree approacht wild forest seedlings apple, Gudulu( Malus Prunifolia), as well as varieties Antonovka ordinary, Grushovka Moscow, Anise, Borovinka. For pear root stocks, you can use seeds of forest pear and cultivated and semi-cultivated varieties. Such crops as hawthorn, Japanese quince, red mountain ash, igra, aronia, are also suitable for pear rootstocks and the plants planted on them are distinguished for their quickness, winter hardiness and short stature, although such unusual grafts are short-lived. Seeds after separation from the fruit should be washed and dried to 6-9% moisture content.
The seeds of cultivars Vladimirskaya, Lyubskaya, Shubnika, as well as antipka( cherry magalebskaya) and cerapadus( a hybrid between cherry and bird cherry) are suitable for rootstocks of cherry. The plum can be planted on seedlings of cultivated and semi-cultivated varieties( Skorospelka red, Tula black, Renclod kolkhoz), cherry plums, cherry felts, thorns and thistles. Dedicated fruits from the bone are undesirable, as they quickly lose their germination capacity.
Seeds of these crops need preplant preparation, called stratification. It consists in that the seeds are kept in a moist state at a lower temperature( first 4-5 ° C, at the end of the stratification period -0-1 ° C) for 3-4 weeks to several months( depending on the species - table.).
Timing of stratification of seeds of fruit and berry crops
| Breed | Stratification duration, days | Breed | Stratification length, days |
| Quince | 70-90 | Plum, turn, mountain ash, | 150-180 |
| Apple tree | 90-110 | Rosehip, barberry | 80-90 |
| Apple-tree and cultured cultivar | 120-130 | Schizandra | 90-120 |
| Cherry felt | 100-120 | Chokeberry | 150-180 |
| Alycha | 120-150 | Hawthorn, viburnum | 210-240 |
| Cherry Ordinary | 150-180 |
Usually, seeds of pome and stone stones are recommended to be washed in water for 3-4 days with a daily change of water before laying in a cold room( for example, in a refrigerator).
This promotes the swelling of seeds and the extraction of substances that inhibit germination. Then the seeds are mixed with any wet and loose substrate( sawdust, peat, coarse sand and the like in a 1: 2 ratio) and placed in polyethylene bags. You can do without substrates, and keep moist seeds in bags;periodically checking and mixing. When the first shoots appear, the stratification temperature is reduced to 0 ° C, placing the seeds in a snowball. The term for reducing the temperature can also be determined by trial germination of seeds.
Seeds of stone fruits quickly lose their germination capacity when dried, so they are stratified beforehand, and when the soil temperature drops to 6 ° C, they are sown in the soil( protected from winter freezing and mice).It is also better to sow the seeds of hawthorn and viburnum from autumn, which have a long term of stratification and often only rise in the second year.