Flowering and Self-Incompatibility in Some of the Superior Apricot (Prunus armeniaca L.) Genotypes Grown in Barzok (Kashan) Climate

Identification of superior genotypes within the rich fruit trees germplasm in Iran is an important task. Eighty suitable genotypes were selected within the 600 genotypes that were grown in the Barzok, Kashan region, then 11 genotypes were considered as the superior genotypes. Besides recording the flowering periods of the 80 suitable genotypes, evaluation of the 11 superior genotypes was recorded during the 2017 and 2018 growing seasons. A 21 days difference at the beginning of flowering was recorded during two years of study. The high variability within the studied genotypes was observed in flower density. The genotype KB1045 with 158 flowers and genotype KB12939 with 60 flowers in 100 cm of shoot showed the biggest and lowest flower density, respectively. The highest fruit set record on 15 days after controlled self-pollination was recorded on genotype KB1045 (53.83 % fruit set) and the lowest was belong to genotype KB4541 (with 0 % fruit set). The microscopic examinations showed well germination of transferred pollens on the self-pollinated stigma. The microscopic fluorescence examination of pollen tube growth in the style at 48, 72, 96, and 120 h after self-pollination showed that very rare pollen tubes reached the ovary, so confirmed the incompatibility of the studied genotypes. Because the studied genotypes were superior in terms of many morphological traits, the obtained results can facilitate further apricot breeding programs on these genotypes.