EVALUATION OF PISTIL ABNORMALITY IN APRICOT USING ITS DIMENSIONS AND FLUORESCENT BRIGHTNESS

Irregular bearing in apricot is a huge problem in the fruit production industry. It is caused by many factors, and in particularly, female sterility. The aim of this study was firstly to investigate the percentage of abnormal pistils based on evaluation of pistil length and ovary diameter. Therefore, flowers of four apricot cultivars namely ‘Nasiri,’ ‘Noori,’ ‘Jahangiri’ and ‘Shahroudi,’ were picked at the full bloom stage in 2 consecutive years and pistil length and ovary diameter were recorded. Then, the linear regression between these factors and initial fruit set percentage (10 days after pollination) was fitted. Results showed that the pistils were grouped in five and three categories according to the length and ovary diameter, respectively. Normal pistils had 10-14 mm length and 1.5-2.5 mm diameter at the FB stage. In a second step, female sterility was studied by fluorescence microscopic methods that confirmed the results of the first step using pistil dimensions. It seems that the pistil dimensions in apricot are suitable indicators for investigating abnormal and sterile pistils. It is worth mentioning that double pistil and multiple ovules will increase the percentage of abnormality of pistils in apricot.