CHILLING REQUIREMENT OF STRAWBERRY CV. 'SONATA' AND 'FIGARO'

‘Sonata’ and ‘Figaro’ are two new Junebearers from the breeding programme of Fresh Forward, The Netherlands. Runner plantlets of both cultivars were transplanted in trays outdoors on 15 July 2006. On 23 November 2006, after receiving 436 chill units in the field, the trayplants were put into cold storage at -1.5°C. After receiving additional chilling up to respectively 1093, 1254, 1414, 1575 and 1735 chill units, the plants were transferred to a heated greenhouse for spring production. Petiole and inflorescences lengths were greatest with the highest chilling amount for both varieties. For cv. ‘Sonata’ the percentage of misshaped fruit decreased with longer chilling duration. However, a chill requirement of 1575 chill units was considered optimum in relation to yield and vegetative development for ‘Sonata’. According to this preliminary trial it appeared that cv. ‘Figaro’ had a much lower chilling optimum. The length of petioles and inflorescences were saturated with 1575 chill units, which is much more chilling than needed for maximum fruit production. The highest total yield was achieved with 1093 chill units. Fruit quality in the main season was superior with the 1254 and 1414 chill unit treatments. ‘Figaro’ plants subjected to an excessive amount of chilling were more vigorous and the fruit production was decreased and delayed. With low chill, ‘Figaro’ was characterized by a reblooming period which resulted in a second harvest period from early June to early July.