Acta Hortic. 410, 455-462 (1996)
Pollination Strategies in Sweet and Sour Cherry Cultivars
Z. Orosz Kovács

Abstract
Changes in the strategy of pollination biology happen very often in sweet and sour cherry cultivars. They are most frequent in varieties with protogynous flowers, which show great adaptation for pollination by wind, beetles, bees and other insects. Protandry is rare, but protogyny, homogamy and delayed homogamy are frequent in sweet and sour cherry cultivars. Homogamy is indicated by a 6 hour rhythm of floral nectar secretion, and dichogamy by a 12 hour rhythm. On the basis of the endogenous rhythms of nectar secretion, sour cherry cultivars may be classified into three groups by their time of production maxima: (a) 3, 9, 15, 21 h; (b) 4, 10, 16, 22 h; (c) 6, 12, 18, 24 h. In cultivars belonging to the third group, three of the production maxima occur at night and dawn; therefore, the role of bees in their pollination is smaller. Wild sour cherries may be classified into the first group and sweet cherry varieties into the third. In certain hybrids of sweet and sour cherry, both the rhythm of sweet cherry and that of sour cherry function, giving secretion maxima every 3 hours.

Prunus Sexual Systems