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Planting and propagation

Seed and vegetative propagation in a fruit crop nursery

For agronomists

3 min read

PLANTING AND PROPAGATION P

When propagating fruit crops in a nursery, two main tasks are addressed: increasing the number of plants and preserving their beneficial cultivar qualities. For this, seed and vegetative methods are used. The choice of method determines the longevity of the future orchard, the speed at which trees enter into fruiting, and their resistance to unfavorable environmental factors.

The seed method is optimal for breeding new cultivars and growing rootstocks. Seed can be stored well, and its sowing is easily mechanized. Seedlings form a powerful tap root system, which ensures high drought resistance and longevity of the trees. Furthermore, seed propagation makes it possible to obtain nursery plant material that is not infected with viral diseases.

  • Start of fruiting for apple seedlings — 10–12 years from sowing
  • Start of fruiting for pear seedlings — more than 12 years from sowing

Most commercial cultivars of fruit crops are heterozygous due to cross-pollination; therefore, when sowing seed, they almost never reproduce the properties of the mother plant. Seedlings are also characterized by genetic diversity and affect the vigor of the grafted cultivar in unpredictable ways.

Vegetative propagation and clonal rootstocks

The basis of vegetative propagation is regeneration — the plant's ability to restore lost tissues and organs. In horticulture, a specific case of this, repair, is applied, where an entire organism is restored from one part: stem cuttings form adventitious roots, while root cuttings form a new above-ground system. In laboratory conditions, it is possible to grow an entire plant even from a single somatic cell using the somatic embryogenesis method.

During vegetative propagation, new cells are formed by simple division, so the chromosomal system is copied completely, and the daughter plant retains all the characteristics of the cultivar. Tissue growth occurs through cell division in the basal part of the shoot, the root apex, and the cambium. The production of clonal rootstocks and the cultivation of commercial cultivars are based on this biological mechanism.

Clonal rootstocks ensure uniformity in the orchard. They guarantee consistent vigor for all trees and possess excellent compatibility with the grafted cultivar, which facilitates the care of the plantings.

When choosing a vegetative propagation method, the agronomist must take into account its biological disadvantages:

  • high probability of transmitting viral infections from the mother plant to the progeny;
  • a less powerful and less deep root system compared to trees grown from seed;
  • lower longevity of the plants in the orchard.

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