Nectar composition in 'Újfehértói fürtös' and 'Pándy 48' sour cherry cultivars

Abstract

The knowledge of nectar composition in entomogamous fruits, including sour cherry cultivars, is of high importance, since pollinator insects have their own taste-preference, which can influence pollination, and hence fruit yield. The floral secretory product of several sour cherry cultivars was studied from 1997 to 2000, in order to determine the floral insect attraction of the cultivars. Here the nectar composition of two major cultivars, an autofertile ('Ujfehertoi furtos') and an autosterile one ('Pandy 48'), will be presented. Samples were collected at the Research and Extension Centre for Fruitgrowing, Ujfeherto, Hungary. Nectar was drained from the flowers with a microcapillary, following a 24-hour isolation. Sugar components of the floral secretory product were determined by thin layer chromatography, quantitative analysis was carried out by densitometry. When evaluating the results, air temperatures and precipitation data during sample taking were also taken into consideration. The nectar of both studied cultivars contains all three major sugar components: sucrose, glucose and fructose. In most seasons the total sugar concentration reached the apicultural threshold value (100 mg/ml). On the basis of the sucrose/(glucose+fructose) quotient the nectar of 'Ujfehertoi furtos' belonged to the sucrose-rich group each year, like the majority of sour cherry cultivars, whereas the secretory product of 'Pandy 48' could be classified into the sucrose-dominant category in one of the seasons. The nectar sugar composition of 'Ujfehertoi furtos' varied to a great extent according to the seasons, while the sugar components in the nectar of 'Pandy 48' were rather stable in the four seasons of study, their amounts changing to a small extent, effected by microclimatic factors.