Agriculture Reference
In-Depth Information
Fig. 9.3
Primocane raspberry
cv. Polka, bred in Poland
polytunnels, have been developed worldwide by growers and researchers in order
to produce red raspberries for the fresh market throughout an extended cropping
season. Primocane-fruiting raspberries are easily manipulated to further extend the
season (Fig.
9.4
), and by using high tunnels a double crop is easily achieved. Differ-
ent methods can be applied but the main system used consists in early summer plant-
ing, which is May in the northern hemisphere) for an autumn harvest and cutting the
canes at fruiting level for an early spring crop. The spring crop is normally low, with
yields depending on chilling requirements of the cultivar used. Some growers prune
canes at ground level after the first crop in order to have a larger fall crop (Oliveira
et al.
1998
). For the early market, long-canes of high yielding floricane-cultivars are
used. Growers can use long-canes lifted from high altitude nurseries or can store
their own canes in refrigerated containers (Oliveira et al.
2002
). The most important
cultivars in this long-cane system are 'Tulameen' 'Glen Ample'. In the primocane-
fruiting types new cultivars are now available, namely 'Polka' (Fig.
9.3
), 'Erica',
'Sugana', 'Amira', 'Kweli', 'Imara', with 'Maravilla' from Driscoll's Strawberry
Associates the most productive with uniform, firm and bright berries. Private breed-
ing programs are becoming increasingly important with public breeding programs
licensing cultivars to specific countries or regions.
Machine harvesting of raspberry remains of considerable importance in many
areas of Europe, particularly for processing and IQF markets (Hall et al.
2002
), and
there are clear differences in machine harvestability between cultivars. Whilst most
breeding of new cultivars is now directed at the more lucrative fresh markets, trials
to examine suitability for mechanical harvesting are still an integral part of some
breeding programmes.
Irrigation and nutrition are also key aspects in maintenance of productivity, as
the use of substrate culture is increasing. Substrate culture is leading to an increased
specialization of raspberry growers, and the use of greenhouse production is grow-
ing in the southern parts of Europe.
