Propagation seed tubers

Simmonds, N. W. (1997). A review of potato propagation by means of seed, as distinct from clonal propagation by tubers. Potato Res., 40, 191-214. 

Humans in all the ancient cultures selected appropriate plants to produce the carbohydrates, fats or oils and proteins needed for their sustenance. Most of the chosen crops produced stmctures (e.g., seeds, tubers, etc.) that the plant had evolved for propagation... 

Hot water treatments are effective in producing clean seed and planting materials. Seed and vegetative propagation materials (such as roots, bulbs, corms, and tubers) may be treated before planting to eliminate some fungal, bacterial, and viral diseases. 

Once a vims is in a host plant it causes the host cell to produce more nucleic acids and proteins from which more vims particles are formed which can then move around the plant in the phloem. All virases are obligate parasites. They are not known to exist as saprophytes. The vims is generally present in every part of the infected plant except the seed, pollen and often the apical meristem. Therefore, if part of that plant, other than the seed, is propagated, the new plant is itself infected, e.g. the potato. The tuber is attached to the stem of the irrfectedplarrt, arrd infection is carried forward when the tuber is planted as seed . 

---