Principles and Methods (1929)
CHAPTER 12

Ivan Michurin

SOME SPECIFIC FEATURES OF OWN-ROOTED FRUIT PLANTS

It is wrong to assert, as many do, that in propagating plants from cuttings, the form or variety of the given plant remains unchanged. It is particularly wrong to say that about the propagation of our fruit trees from cuttings. Here it is necessary to hear in mind, first of all, the influence of the replacement of the root system of the cuttings taken from trees grafted on the stock of a wild species by their own roots, which inevitably affects the quality of the variety, although in a good way.

1Cuttings are up to 20 cm. in length from a single shoot or one with branches.

It follows, then, that the variety undergoes partial change. To this it must be added that here we may come across a sport deviation (bud variation) of one of the buds of a cutting (this, in general, happens rather rarely in old, long-existent varieties of plants, but in hybrids, particularly at a young age, up to ten years, sport deviations must be regarded as a common occurrence). Lastly, when raising hybrid seedlings we also inevitably come across a constant, regular and gradual change in the entire habit (external appearance) of the hybrid, beginning from the first year of its development from the seed to the first five to ten years of bearing. All seeds of hybrid origin, when germinating, produce, as a consequence of atavism (a reversion to ancestral characters), all the parts of the aerial habit of a wild species, which, as the seedling develops, both in the first year of growth and in subsequent years until the plant reaches maturity, differentiates only gradually, undergoes a whole series of changes in form and finally assumes the structure of a cultivated species. Further, if an adult tree of a hybrid that is already beginning to bear is cut to the root neck, its offshoots will again have the appearance of a wilding, and in their subsequent development will go through all the changes that the seedling went through after germination from the seed. And yet, if an adult bearing tree grown from a cutting that was taken from the seedling is also cut to the root neck, the offshoots from the root neck will not have the structure of a wilding, but will at first have the form that the cutting had, and from this form will go through all the other forms until bearing time; however, a considerable deviation for the better is observed owing to the improved structure of a different root system, which is incapable of giving at first offshoots of a wild type. I performed these experiments as far back as the end of the 'eighties and repeated them in 1915, but only up to the second vegetative generation, i.e., I took the cutting from an already hearing hybrid seedling (a Reinette Bergamotte apple). It is my intention to repeat the experiments on subsequent vegetative generations, i.e., in the third generation to plant cuttings not from the seedling, but from the first tree raised from a cutting, etc. To make this clearer I give an illustration [Fig. 43] where A is a two-year-old seedling; B is a cutting of the second vegetative generation,1 the root system of B is already improved and its root neck already gives offshoots of the structure of B and not of a wilding as in A; C is a plant raised from a cutting taken from B in the third year of growth. The root system of C is stilt further improved and gives offshoots shaped like C, and so forth (see dotted arrows).

Fig. 43. A—two-year-old seedling; B—cutting from second vegetative generation; C—cutting from third vegetative generation

Then, after rooting by a method that I have devised, which even fruit growers of little experience can employ, the cuttings are planted in the bed when the leaves are fully developed. The cutting specimen bears fruit earlier than the seedling did. The cutting specimen of the second generation should bear fruit even still earlier, and so forth. This last assumption is now being tested on eighty varieties. In addition to all that has been said, it must be noted that only by repeating this rooting of cuttings in several vegetative generations is it fully possible to develop in the new variety of fruiters the ability to take root easily from a cutting simply planted in the bed.