Floral nectar production and composition in quince cultivars and its apicultural significance

The sugar composition of the floral nectar was studied in 22 mainly Hungarian local quince cultivars in 2004. The material for investigation was taken from the quince genebank of the Research and Extension Centre for Fruitgrowing, Újfehértó, Hungary. The three main sugar components of the nectar were glucose, fructose and sucrose. Sucrose was present in the greatest amount in the nectar of all investigated quince cultivars. Glucose which is the least sweet among the three main nectar sugars for bees was present in the least amount. The nectar of most cultivars contained more fructose than glucose. The amount of the total nectar sugars was the lowest in cv. 'Pear-shaped Noszvaji' and the highest in cv. 'Kúti'. According to the Baker-quotient (S/F+G), the majority of the quince cultivars belonged to the sucrose dominant category. However, the cultivars 'Mezőkövesdi', 'Apple-shaped Dunabogdány' and 'Váli' had sucrose-rich nectar. The concentration of floral secretory product in all cultivars reached the threshold of bee visitation. The nectar refraction was lower at the end of bloom than in full bloom while flowers contained more nectar at the previous stage. The above results are important from the viewpoint of pollination biology, apiculture and defence against fire blight