Screening and monitoring of watermelon source material by components of the vegetation period in the conditions of the forest-steppe of Ukraine

Relevant in the selection of each crop, including watermelon is a comprehensive study of the source material to identify sources of valuable traits and include them in the selection process in order to expand the genetic diversity of the culture. According to the results of research, to create a new source material for heterosis selection of watermelon, screening and monitoring of the vegetation period duration (number of days from germination to ripening) and its components 118 (101 varieties, 17 hybrids) genotypes of watermelon in the forest-steppe of Ukraine have been conducted. Research methods are generally accepted: field experiment, observation, accounting, analysis, statistical. According to the results of determining the duration of the components of the vegetation period, the samples were divided into five groups of ripeness: early (65–80 days) – 80 (68 %), medium-early (81–85 days) – 14 (12 %), medium (86–95 days) – 18 (15 %), medium-late (96–105 days) – 4 (3 %) and late (106 days) – 2 (2 %). Variety-samples, selected by morphological and economically valuable characteristics, belong mainly (80 %) to early and medium-early. Only 6 % of genotypes belong to the medium-late and late-ripening groups. 52 samples with the smallest separate interphase periods were isolated. According to the results of the research, 8 sources with the high early ripeness were identified, the vegetation period of which was 66–70 days: Yellow early 108105 (66 days), Karapuz 108109, Surprise 108121 (67 days), Gift of the sun 108109, Lezheboka honey 108116, Thailand №1 108153 ( 69 days), Sweet Diamond 107874, Northern Lights 108127 (70 days). Sources are involved in the selection process