Saila Karhu

MTT Agrifood Research Finland, Horticulture, Toivonlinnantie 518, FIN-21500 Piikkiö, Finland, e-mail: saila.karhu@mtt.fi

A breeding programme was carried out in order to develop sea buckthorn (Hippophaë rhamnoides) cultivars with good adaptability to northern climatic conditions, combined with high disease resistance and quality yield. Seedlings and selections originating from Finnish, Central European and Caucasian wild strains and Altai cultivars were evaluated at different test sites. Notable variation occurred in several characteristics both between and within progenies. Such characteristics as growth vigour, thorniness, content of vitamin C in berries and disease resistance correlated with the traits of parental pistillate plants. Progenies of Altai cultivars were seriously affected by stem canker (Stigmina sp.). Parental plants originating from the Baltic Sea region transmitted resistance towards this disease. The pistillate cultivars named ‘Terhi’ and ‘Tytti’ and the staminate cultivar named ‘Tarmo’, all based on Finnish natural strains, were released for cultivation. They expressed moderate growth vigour, good disease resistance and high adaptability to northern growing conditions. The berries of cvs. Terhi and Tytti usually weigh 0.5-0.6 grams. The fruit stalk is short, 2 mm, and a mass of ca. 220 grams is needed to detach berries from the shoots. The berries are rich in acids and low in sugars, and their content of vitamin C is high, ranging between 183-252 mg per 100 g in cv. Terhi and between 217 and 359 mg per 100 g in cv. Tytti. Auxin indole-3-butyric acid is essential for good rooting of softwood cuttings and for assuring proper early growth of plants.