Journal of Berry Research 1 (2010) 91–101 DOI:10.3233/BR-2010-010 IOS Press 91 Development and quality of cloudberry (Rubus chamaemorus L.) as affected by female parent, male parent and temperature Inger Martinussen a,∗ , Eivind Uleberg a , Gordon J. McDougall c , Derek Stewart c and Olavi Junttila b a Norwegian Institute for Agricultural and Environmental Research, Bioforsk Nord Holt, Tromsø, Norway b Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway c Plant Products and Food Quality, Scottish Crop Research Institute, Dundee, Scotland Abstract. In this study we investigated the interaction between temperature and genotype on fruit development and levels of total phenols and anthocyanins in cloudberry. The experiment was done in a phytotron using one female (‘Fjellgull’) and one hermaphroditic (‘Nyby’) cultivar. Plants were grown at 9, 12, 15 and 18 ◦ C in 24-h photoperiod. The female cultivars were pollinated with pollen from a male (‘Apollen’) clone and from the hermaphrodite clone. Parthenocarpic fruit development was induced by gibberellic acid (GA 3 ). Ripe berries were frozen individually at -80 ◦ C and stored until analyses. There was a linear, double logarithmic relationship between temperature and number of days from pollination/GA 3 -treatment to ripening. ‘Fjellgull’ had significantly larger berries than ‘Nyby’, and the largest berries were obtained at 12 and 9 ◦ C. Pollen clone did not have a significant effect on berry size. GA 3 induced parthenogenesis in ‘Fjellgull’ and partial parthenogenesis in ‘Nyby’. In ‘Fjellgull’, the parthenocarpic berries were comparable to pollinated ones at low temperatures, but at 18 ◦ C their development was restricted. The level of total anthocyanins was significantly higher in ‘Fjellgull’ than in ‘Nyby’, and these levels were significantly enhanced at 9 and 12 ◦ C compared to higher temperatures. Levels of total phenolic compounds were not significantly affected. In conclusion, the present results indicate that low temperature is favourable both for size and quality of cloudberries. Keywords: Cloudberry, temperature, gibberellin, berry development, anthocyanins, phenols, Rubus chamaemorus 1. Introduction Cloudberry (Rubus chamaemorus L.) is a circumpolar plant species [13] growing on peat land, preferably Sphagnum bogs. Berries of cloudberry have traditionally been used by people living in these areas, and currently cloudberry is an economically important product for domestic and commercial use, particularly in Fennoscandia. The first cloudberry cultivars released in Norway, two female and two male cultivars, were selected for stability and high number of carpels (‘Fjellgull’ and ‘Fjordgull’) and for abundant pollen production (‘Apollen’ and ‘Apolto’) [24]. Unisexuality of cloudberry is one obstacle for cultivation, and clones with bisexual (hermaphrodite) flowers have been sought for some time. Such clones have been reported [9], and recently one hermaphrodite cultivar (‘Nyby’) was released in Finland (Uosukainen 2005, pers. comm.). In addition, cloudberry also has an ability to produce parthenocarpic fruits after a treatment with gibberellic acid (GA 3 ) [15]. ∗ Corresponding author: Inger Martinussen, Norwegian Institute for Agricultural and Environmental Research, Bioforsk Nord Holt, Box 2284, N-9269 Tromsø, Norway. Tel.: +47 40604100; Fax: +47 77655143; E-mail: inger.martinussen@bioforsk.no. 1878-5093/10/$27.50 © 2010 – IOS Press and the authors. All rights reserved