Functionality of embryo sacs as related to their viability and fertilization success in sour cherry

The functionality of embryo sacs in relation to their viability and fertilization success was studied over a 2-year period in the sour cherry cultivar 'Cacanski Rubin' during full bloom under field conditions. The occurrence of abnormal embryo sacs resulted in a varying number of functional embryo sacs assessed at the onset of full bloom and had a direct effect on the number of viable embryo sacs. The functionality of embryo sacs, represented by the number of normally developed embryo sacs, which varies from year to year, is approximately equal to the initial number of embryo sacs with embryo, namely, it is the factor which contributes to fertilization success in this cultivar. (C) 1999 Elsevier Science B.V. All rights reserved.