Oddmund Frøynes
Adviser (OAP Agreement)
(+47) 959 06 027
oddmund.froynes@nibio.no
Place
Ullensvang
Visiting address
NIBIO Ullensvang, NO-5781 Lofthus
Authors
Milica Fotirić Akšić Dragana Dabić Zagorac Marko Kitanović Kristina Đorđević Maja Natić Oddmund Frøynes Mekjell MelandAbstract
Commercial production of sweet cherries is possible up to approximately 60° N latitude in Norway and is among the most economically important fruit crops in the country. The harvest is late, but yields are very high, and the fruit is intended solely for the fresh market. The objective of this study was to assess whether sweet cherry can be grown in pots and to determine fruit quality (sugar, acid, polyphenol, and mineral content) of three sweet cherry cultivars (‘Van’, ‘Lapins’, and ‘Regina’) grown in high tunnels with varying levels of fertigation (F) and the application of slow-release (SR) fertilisers. Trees were planted in 35 L plastic bags, trained as spindle trees, with a spacing of 1 × 2.5 m (4000 trees/ha). The tunnel was covered with polythene from flowering until harvest. Fruit produced in pots had low levels of sugars and acids and high levels of phenolic acids and flavonoids, while the mineral content depended on treatment and cultivar. The main sugar components (glucose and fructose), the sweetness index, phenolic acids (chlorogenic acid and ferulic acid), flavanols (catechin, rutin, quercetin, and hyperoside), and minerals (P, K, Mg, Ca, and Na) were much higher in the F treatment. SR treatments were more effective in increasing the content of acids (shikimic, malic, and quinic) and total phenolic content (TPC). Radical scavenging activity (RSA) and total sugars showed no statistically significant differences between the treatments studied. ‘Lapins’ fruit obtained from the fertigation regimes (when Kristalon brown + Calcinit + Magnesium-sulphate were added from mid-April to 1 September and plain water for the rest of the season, up to an electric conductivity (EC) of 0.5 and 1.0) contained the highest levels of minerals (P, K, Mg, Ca). The ‘Van’ cultivar from F treatments, especially VF2 (when Kristalon brown + Calcinit + Magnesium-sulphate were added from mid-April to 1 September and plain water for the rest of the season, with EC 1.0) and VF3 (when Kristalon brown is added in July, Kristalon brown + Calcinit + Magnesium-sulphate in August, and plain water for the rest of the season) had the highest sweetness index, glucose, fructose, chlorogenic acid, ferulic acid, and hyperoside in sweet cherry fruit. ‘Regina’ under the RSR1 (50 g Multicote and 30 g chalk lime per tree) and RSR2 regimes (100 g Multicote and 30 g chalk lime per tree) produced fruit with the highest acid components, RSA and TPC. This suggests that sweet cherry trees can be grown in pots under high tunnels, but nutrition should be adjusted for each cultivar according to its physiological responses to specific microclimate conditions.
Abstract
Sweet cherries are grown in areas with suitable local climatic conditions up to 60°N in Norway. All orchards have high density planting systems and are rain covered from the bloom to the end of the harvest. All orchards are fertigated and the production is aimed to supply the domestic market with high quality fruit from early July and to the end of August. At NIBIO Ullensvang a large number of sweet cherry cultivars and advanced selections from worldwide breeding programs have been evaluated continuously since 1959. However, despite of relatively extensive list of recommended cultivars, cv. 'Lapins' has become dominant with 60% of the total sweet cherry volume in Norway, and causes high pressure in the market when too much fruit are delivered at the same time. The most effective way to extend the cherry market season is an introduction and cultivation of new early or late ripening sweet cherry cultivars. During the last years, approximately fifty cultivars and advanced selections have been evaluated. Along with earlier recommended cultivars ‘Folfer’, ‘Van’, ‘Lapins’, ‘Regina’ and ‘Sweetheart’, the following cultivars can be recommended for extended testing commercially: a) for early season: ‘Adelka’ (for local market), ‘Sweet Aryana’ and ‘Bellise’ (primary for local market), b) for mid-season: ‘Edit’, ‘Brooks’ (limited testing) and ‘Grace Star’, c) for late season: ’SPC 342’, ‘LaLa Star’, ‘Royal Edie’, ‘Tamara’ and ‘Royal Helen’.
Abstract
Sweet cherries are grown in areas with suitable local climatic conditions up to 60°N in Norway. All orchards have high density planting systems and are rain covered. The most common system now is multibay high tunnels systems where the trees are under plastic cover from the bloom to the end of the harvest. All orchards are fertigated and the production is aimed to supply the fresh fruit domestic market with high quality fruit from early July and to the end of August. At NIBIO Ullensvang, western Norway a large number of sweet cherry cultivars and advanced selections from worldwide breeding programmes have been evaluated continuously since 1959 and several cultivars have been recommended from this programme for commercial production during the last decades. During the last six years approximately fifty cultivars and advanced selections grafted on the rootstock Gisela 6 have been tested. Important objectives were to obtain large and precocious yields, with important quality parameters like fruit size, fruit firmness, soluble solids, fresh appearance, good flavour and resistance against irrigation induced cracking. Based on the results from the recent testing program, the following cultivars are currently recommended for the fresh fruit market: a) for early season: ‘Adelka’, ‘Pacific Red’, ‘Sweet Aryana’ and ‘Bellise’, b) for mid-season: ‘Brooks’, ‘Giant Red’, ‘Grace Star’ and ‘Folfer’ c) for late season: ‘Van’, ,’SPC 342’, ‘LaLa Star’, Royal Edie’, ‘Tamara’ ‘Lapins’, ‘Royal Helen’, ‘Regina’ and ‘Sweetheart’.