Hermoplasma of common watermelon ((Citrullus lanatus (Thumb.) Matsum. et Nakai) in Ukraine as the basis for the selection of new varieties and hybrids

Abstract

This article summarizes current global approaches to the use of watermelon germplasm and analyzes the potential of Ukrainian genetic resources for breeding new varieties and hybrids. The study utilized the gene pool of common watermelon (Citrullus lanatus (Thumb.) Matsum. et Nakai) available at the Institute of Vegetable and Melon Growing of the National Academy of Agrarian Sciences of Ukraine. Screening (2023–2025) of 24 homozygous watermelon lines was conducted for phenological, morphological, and economically valuable traits; the data obtained were included in the analysis of the gene pool. Based on the results of the analysis, a description of the general watermelon germplasm population was provided, and the role and significance of Ukrainian collection samples in modern breeding programs were determined. The Ukrainian watermelon gene pool is represented by 645 watermelon samples of various geographical origins. Samples with a monoecious type of female flowers account for 46 %. Based on the results of the phenological study, the general population was divided into maturity groups: early-maturing – 64 %, mid-early – 19 %, mid-maturing – 14 %, and mid-late – 3 %. Twenty-four samples were identified as having the shortest duration of the period from mass emergence to physiological maturity (56–60 days). Yields of samples from the general population of the watermelon gene pool ranged from 5.1 to 74.2 t/ha
(Am = 69.1), with an average of 29.2 t/ha. Sources were identified that significantly exceeded the standard by 5 to 42% in terms of yield, with yields ranging from 41.1 to 74.2 t/ha. This includes 34 samples. The level of the “marketability” trait ranged from 44 to 100 % (Am = 56), with an average trait value in the general population of 94 %. The level of expression of the “average marketable fruit weight” trait in the general population ranged from 2.0 to 6.5 kg (Am = 4.4), with an average trait value in the general population of 3.2 kg. Watermelon germplasm is a key factor in the successful breeding of new varieties and hybrids. Ukrainian watermelon genetic resources have high breeding value and can play an important role in the creation of adapted, productive, and competitive varieties and hybrids. Research on the comprehensive evaluation and selection of watermelon breeding material has allowed for the identification of genotypes that correspond to the modeled traits, and their inclusion in the breeding process to create varieties and hybrids with high adaptability will increase the efficiency of breeding efforts, thereby contributing to ensuring food security in Ukraine.