PROTECTED OVERWINTER STRAWBERRY CULTURAL SYSTEMS IN JAPAN: ORIGIN, RENOVATION, AND CONSECUTIVE IMPROVEMENTS

The open-field cultivation of strawberries commenced in a suburb of Tokyo during the period of 1892 and 1896, and later on, it expanded gradually to the suburbs of large cities all over the country.
In the early 1950s, protected cultivation under plastic covers (vinyl chloride) was introduced to strawberry-growing operations. Since then, this has spread to the entire country, together with a new system and newly bred cultivars. The planted hectarages and the production amounts increased rapidly year by year during 1960 to 1972.
Currently, over 90% of strawberry fields are covered with plastic. However, later on in the initial stage of the introduction of protected cultures, there existed various modified subsystems, such as early or delayed harvesting and so on. Recently, these systems under plastic are concentrated into two major types of overwinter cultures used by the June-bearer or the summer-autumn culture of the ever-bearer. The former system is important both economically and for production amount.