Polymorphism of traits of flower and fruit of the Tsumi apple tree (Malus zumi (Matsum.) Rehder)

The Tsumi apple tree is a valuable crop due to the presence of a gene for resistance to powdery mildew, abundant annual fruiting and a special decorative effect during flowering and fruiting. Its breeding potential has been little studied; therefore, it is necessary to study the morphometric characteristics of a flower and a fruit and establish connections between them. The collection of flowers and fruits of the Tsumi apple tree was carried out in the laboratory of cultivated plants of the Tsytsin Main Botanical Garden in 2021. The coefficients of variation and correlation according to Spearman were determined. It was found that the polymorphism of flower traits is at a very low level (from 4.4% to 14.2%). The number of flowers per inflorescence varies within 15.9%, which corresponds to the average level of polymorphism, as well as in the weight of the fruit (17.3%) and in the weight of seeds (19.5%). Variations in the length of the peduncle, the number of seeds, the length of the fruit, and the diameter of the fruit are at a very low level (6.9-13.6%). A significant number of reliable inverse (negative) correlations were found between signs of moderate strength (0.5 <r <0.6): a strong relationship between fruit weight and anther length (r = -0.73), fruit length and filament length (r = -0.71). A strong positive relationship was found between the following traits: fruit weight and fruit diameter (r = 0.79), seed weight. Keywords: POLYMORPHISM, FLOWER, CRABAPPLES, SORBOMALUS, MALUS ZUMI, TSUMI APPLE TREE, VARIABILITY, MORPHOLOGY