MORPHOMETRIC ANALYSIS OF ASIMINA TRILOBA (L.) DUNAL FRUITS AND SEEDS FROM THE KHOROL BOTANICAL GARDEN COLLECTION

Abstract

Background. Pawpaw – Asimina triloba (L.) Dunal is a promising fruit crop for introduction in Ukraine, yet the expansion of the industry remains constrained by the limited availability of superior clonal material. Successful commercialization in new cultivation areas requires comprehensive studies of the species’ biological performance under local environmental conditions. This study aimed to evaluate the morphometric characteristics of fruits and seeds from the collection of the Khorol Botanical Garden and to characterize the phenotypic variability of the studied germplasm under the environmental conditions of the Left-Bank Forest-Steppe of Ukraine. The results provide a basis for the identification of promising genetic resources for further breeding and cultivation.
Materials and Methods. In 2025, 13 genotypes, including the Italian cultivar ‘Prima 1216’ and hybrid seedlings originating from the ‘Michurinka’ cultivar, were analysed. Morphometric parameters (weight, length, width, thickness) and shape indices were calculated for fruits (n = 10 per genotype) and seeds (n = 20 per genotype). Seed-to-fruit ratio was also calculated. Statistical analysis included one-way ANOVA, Fisher’s LSD test, and Pearson correlation coefficients (P ≤ 0.05).
Results. The linear dimensions of pawpaw fruits ranged from 6.2 cm to 8.0 cm in length and from 3.8 cm to 5.3 cm in width. Fruit weight exhibited significant variability (CV = 37.5%), ranging from 46.0 g to 136.3 g. ‘Prima 1216’ produced significantly larger fruits than all other evaluated genotypes, reaching a maximum fruit weight of 195.7 g. The mean seed count per genotype varied from 6.7 to 11.1. ‘Prima 1216’ fruits exhibi­ted an excellent seed-to-fruit ratio of 3.7 %. In the hybrid genotypes ‘Tsukerkova’ and ‘Furshetna’, which performed best in this regard, the seed-to-fruit ratios were 7.3 and 7.9 %, respectively. Seed weight, length, and width varied between 0.7 g and 1.0 g, 18.4 to 26.7 mm, and 10.0 to 13.6 mm, respectively. Correlation analysis showed that fruit weight was most strongly associated with fruit width (r = 0.97). Fruit size was negatively correlated with seed-to-fruit ratio (r = -0.78 to -0.87), indicating an inverse association between fruit size and the relative proportion of seeds.
Conclusions. The studied genotypes exhibited high phenotypic diversity in the conditions of the Left-Bank Forest-Steppe of Ukraine. ‘Prima 1216’ exhibited the lowest seed-to-fruit ratio (3.7 %), followed by the hybrid selections ‘Tsukerkova’ (7.3 %) and ‘Furshetna’ (7.9 %). These genotypes represent promising genetic resources that deserve further evaluation for breeding programmes and subsequent commercial cultivation.