UNUSUAL GROWTH OF POLLEN TUBES IN THE OVARY OF PLUM GENOTYPES DEVELOPED AT FRUIT RESEARCH INSTITUTE ČAČAK (SERBIA)

Unusual growth of pollen tubes in different pollination variants (self-, cross- and open pollination) was observed in the ovary of six promising plum (Prunus domestica L.) genotypes developed at Fruit Research Institute (FRI), Čačak (hybrids 38/62/70, IV/63/81, 32/21/87, 34/41/87 and 22/17/87 and cultivar ‘Nada’) in Serbia. The cross-pollination was performed using the pollen of plum cultivar ‘Čačanska Lepotica’. The occurrence of unusual pollen tubes growth in the ovary was studied over the three-year period (2009‒2011) using fluorescent microscopy method. The appearance of unusual growth of pollen tubes in the ovary of all studied genotypes during the whole examination period was recorded in the region of the obturator and the micropyle, with or without further growth of the pollen tubes to the nucellus. Several different types of unusual growth of pollen tubes were observed, i.e. the growth of pollen tubes in opposite direction in relation to the nucellus, the curling up of pollen tubes, the branching of pollen tubes, as well as combinations of some of the above mentioned types of specific pollen tubes growth. Average values of all analyzed genotypes showed that the highest frequency of the ovaries with unusual growth of pollen tubes was determined in the open pollination variant (7.89%), followed by the cross-pollination variant (6.27%), while the smallest frequency was found in the self-pollination variant (3.12%).