An Evaluation of the States of Incompatibility and Sterility in Four Iranian Commercial Apricot Cultivars

Apricot (Prunus armeniaca), palys an important role in fruit production industry in Iran. Irregular set of fruit, caused by either sterility of flower organs or incompatibility has been the main problem in apricot production over the years. In this study, it has been attempted to determine these phenomena for four apricot cvs. namely ‘Shahroodi’, ‘Nasiri’, ‘Jahangiri’ and ‘Noori’ through the methods of controlled pollination, study of fruit set (percentagewise) within three dates (10, 30, 60 days after pollination), an evaluation of pistil length and diameter, as well as study of pollen germination were carried out in Karaj climatic conditions. The experiment was conducted in the frame work of a factorial one in CRD with diallele crosses. The results of pollen germination revealed that there was not any male sterility evident in the cultivars. Three dates were considered for an assessment of fruit set (percentage wise) according to natural abscission of fruitlets. Initial fruit set for ‘Jahangiri’ was high enough, suggesting not any female sterility. The data from pistil length and diameter at ballon stage of flowers also confirmed these results. Fruit set at second stage (30 days after full bloom) showed that all the four cvs. were prone to be self-incompatible but not reciprocally cross-incompatible. ‘Shahroodi’ and ‘Nasiri’ with poor fruit set at stages 1 and 3, were considered to suffer from female sterility and embryo sac abnormality. To some extent, pollen germination test proved that none of the four examined cvs. were suffering from male sterility in the process of pollination. Interaction effect of pollen × pistil was significant showing different behaviors of pollen type for germination and growth conditions provided by different pistils. All four cultivars were self-incompatible and as for ‘Shahroodi’ and ‘Nasiri’ the female sterility was observed as higher than that of other cultivars. Cultivar ‘Jahangiri’ did not suffer from female sterility.