Influence of cold storage on growth, productivity and root reserves of 'Kwanza' raspberry
The long-cane raspberry production system under tunnels allows fruit production throughout the year. However, the effect of plant origin and the duration of the artificial chilling period on plant productivity are not yet fully understood. The objective of this study was to evaluate the influence of cold storage duration in the production and development of Kwanza raspberry in Odemira, Portugal (37°3505N; 8°4036W). Plants of Portuguese and Dutch origin were stored at 1°C for 11 and 15 weeks (short-term), later referred as treatments STPt and STHol, respectively, or for 42 and 46 weeks at -1°C (long-term), later referred as treatments LTPt and LTHol, respectively. These plants were grown in pots with coconut fiber substrate with varying long-cane density per pot, but with the same density m‑1 at planting. Short-term plants from Portugal and Holland produced 3919 and 4409 g of commercial quality fruit m‑1, respectively and the production of long-term plants from Portugal and Holland was 744 and 806 g of fruit m‑1, respectively. Short-term plants were planted later (February) than long-term plants (November) and benefited from longer photoperiod and higher temperatures than long-term stored plants. This increased availability of light and temperature had a pivotal role to achieve not only higher yield, but also higher fruit quality since fruits from plants of short-term storage were larger and less misshapen. Overall, plants that stayed in the cold for a shorter period were more vigorous, less susceptible to diseases, and had a greater number of fruiting laterals. Moreover, starch root percentage was different (P<0.05) between treatments. STPt and STHol had 3 and 5 mg of starch 100 mg‑1 of root dry weight, respectively whereas STPt and STHol had 0.7 and 0.8 mg of starch 100 mg‑1 of root dry weight, respectively. These data demonstrate that long duration storage leads to a greater consumption of root carbohydrate storage resulting in lower productivity. Strategies to increase energy storage in the root should be developed and implemented. Currently, farmers need to evaluate whether out-of-season production using long-term stored plants is economically viable despite lower productivity.
Oliveira, P.B., Moreira, B.R. and Oliveira, C.M. (2020). Influence of cold storage on growth, productivity and root reserves of 'Kwanza' raspberry. Acta Hortic. 1277, 195-200
long-cane, long-term storage, short-term storage, off-season production, Rubus idaeus