|Authors: ||P.B. Oliveira, E.J.B. Sousa, C. Serrano, C.M. Oliveira|
|Keywords: ||Rubus sp., long canes, off-season production, starch|
Long cane production of raspberries has increased considerably in recent years.
Normally, growers in southern regions obtain the canes from northern nurseries in January, plant or place them inside of tunnels, and harvest the fruit in the spring.
However, with an increase in substrate production, some growers are beginning to use their own canes, breaking dormancy with artificial chilling.
A trial was set up to determine the effects of cold storage on carbohydrate reserves and its influence on growth and yield.
Two summer-bearing cultivars, 'Tulameen' and 'Glen Ample' were placed into cold storage (4°C) on January 31, 2013 and removed on February 27, March 27, and April 30 for a total of 648, 1320, and 2136 chilling hours, respectively.
Control treatments received 450 chilling hours and had no artificial chilling.
Bud break and growth of the lateral branches were similar among all treatments in both cultivars, except for the 'Glen Ample' control.
However, yield was significantly affected by chilling in 'Tulameen'. In this case, yield was greatest in the control and with 648 chilling hours, averaging 1.4 and 1.0 kg cane-1, respectively.
Yield in 'Glen Ample' was low in all treatments and ranged from 0.04 kg cane-1 in the control to 0.6 kg cane-1 with 1320 chilling hours.
Starch concentration in the roots was high both before and after chilling in 'Tulameen' but declined considerably after chilling in 'Glen Ample'. The results suggest that carbohydrate reserves are critical in long cane production, even when done in container systems, where the substrate and root system remain undisturbed.
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