Morphological and biochemical characteristics of medlar (Crataegus germanica) fruits in the Forest-Steppe of Ukraine
Morphological and biochemical characteristics of medlar (Crataegus germanica) fruits in the Forest-Steppe of Ukraine

Summary/Abstract: This study was carried out to determine the morphological traits of the fruit as well as the dry matter, sugars, and organic acids of medlar (Crataegus germanica (L.) Kuntze) genotypes which were grown near Kyiv, Ukraine in 2022–2024. A total of 15 genotypes were evaluated in the study, including 14 varieties originating from Western, Central, and Eastern European countries, the North Caucasus, and Iran, and one local semi-wild form. Significant differences were detected among the genotypes on the morphological and biological characters and on the chemical composition of the fruit. Fruit diameter ranged from 16.97 to 42.17 mm, fruit weight from 2.39 to 34.37 g, pyrena percentage from 0.00% to 16.82%. ‘Apyrena’ and ‘Seedless’ are characterized by the complete absence of pyrenas and seeds in the fruit. In terms of fruit diameter and fruit weight genotypes are grouped into very small fruit (‘Apyrena’), small fruit (semi-wild medlar, ‘Seedless’ and ‘Nottingham’), medium-sized fruit (‘Gojtkhivska’, ‘Monstruose d’Evreinoff’, ‘Haidegger’, ‘25-hrammovaja’, ‘Elburs’, ‘Silberberger’, ‘Delice des Vannes’, and ‘Sladkaja Drachyova’), and large fruit (‘Holland’, ‘Dutch Giant’, ‘Dniprovska’, and Flanders Giant® ). The correlation between fruit diameter and fruit weight is very strong, r = 0.98. The weight of pyrenas in the fruit is moderately correlated with the fruit weight, r = – 0.45. Medlar pyrenas varied in length from about 8.75 to 13.53 mm, in width from 6.06 to 11.01 mm and in thickness from 3.97 to 7.12 mm. The largest pyrenas were found in ‘Dutch Giant’, ‘Holland’, Flanders Giant® , ‘Dniprovska’, and ‘Gojtkhivska’, accordingly 0.33, 0.33, 0.35, 0.37, 0.48 g; the smallest pyrenas (0.11 g) were found in semi-wild medlar fruit. The fruits of the ultra-early ‘Hoitkhivska’ variety began to soften on the tree in late October. The early ripening varieties ‘Elburs’, ‘Haidegger’, ‘Nottingham’, ‘Silberberger’ and semi-wild medlar reached consumer ripeness when stored indoors at room temperature for two weeks. Late-ripening varieties include ‘Delice des Vannes’, ‘Dutch Giant’, Flanders Giant®, ‘Holland’, ‘Monstruose d'Evreinoff’, ‘Sladkaja Drachyova’, and ‘25-hrammovaja’. Fruits of ultra-late varieties ‘Apyrena’, ‘Dniprovska’, and ‘Seedless’, were harvested in the late October without bletting. In December, fruit after repeated freezing outdoors on the tree, when the flesh had reached a soft consistency, consisted of dry matter from 19.7% to 26.2%. The total sugar ranged from 8.5% to 17.1%, monosaccharides from 8.3% to 16.0%, titratable acidity from 0.28% to 1.12%, ascorbic acid from 2.94 to 4.84 mg/100 g, sugar/acidity index from 10.0 to 50.8.

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