MAIN PERIODS OF GROWTH AND DEVELOPMENT OF F1 CUCUMBER HYBRIDS AND THEIR YIELDS DEPENDING ON WEATHER

Abstract

Purpose. To evaluate effects of weather on growth and development of cucumber plants, lengths of the main interphase periods, and cucumber yield the Left-Bank Forest-Steppe of Ukraine; to select breedingvaluable genotypes for heterosis breeding under climatic changes. Methods. Field, analytical, measuring, statistical. Results. The study was conducted outdoors at the Institute of Vegetable and Melon Growing of NAAS in 2019–2020. The weather in the study years varied significantly, allowing us to assess its influence on phenological processes of growth and development of cucumber plants. Summarizing the results, we established that sufficiently high average daily air temperature (25.3–25.8 °С), a large amount of unevenly distributed precipitation (0–104 mm), with little or no precipitation during certain phases of cucumber development, significantly affected the growing period length and yield of the cucumber hybrids under investigation. We found that the onset of mass anthesis of female flowers did not vary significantly across the years, averaging 33–36 days. (35 days in the check accession). Fructification started on day 37–40 in 2019 and on day 42–45 in 2020, which was 4–6 days later. Fructification lasted 32–40 days in 2019 and 20–24 days in 2020, which was 12–16 days longer. Analysis of the cucumber yield dynamics over the study years showed that the weather in 2019 was more favorable for the growth and development of cucumber plants. Thus, in 2019, the total yields of hybrids ranged 20.8 t/ha to 64.9 t/ha. In 2020, at high temperatures and low air humidity, the total yield was 12.7–26.9 t/ha, which was significantly lower (by 41.4–61.0 %). Conclusions. The weather in the study years reflected the climate instability in the Forest-Steppe of Ukraine. The lengths the main periods of the growth and development of cucumber hybrid plants and their yields were revealed to vary significantly under variable growing conditions. We selected hybrids with annual parameters that would be valuable for further breeding: by early ripeness – F1 ‘BD 96-18’ / ‘Tsezar’, F1 ‘RD 96 2-95’/ ‘Dzherelo’, F1 ‘RD 96 2-95’ / ‘Heim’ and F1 ‘Mah-62’ / ‘Toma-18’ (42 days); by fructification length – F1 ‘RD 96 2-95’/‘Dzherelo’ (35 days), F1 ‘Mah-62’ / ‘Toma-18’, F1 ‘BD 96-18’/ ‘Heim’ and F1 ‘RD 96 2-95/‘Heim’ (32 days); by yield capacity – F1 ‘Mah-62’ / ‘Toma-18’ (45,9 t/ha), F1 ‘BD 96-18’/ ‘Toma-18’ (39,3 t/ha), F1 ‘Krak’ / ‘RD-96 2-95’ (36,8 t/ha), F1 ‘RD 96 2-95’/ ‘Heim’ (35,8 t/ha), F1 ‘BD 96-18’/ ‘Heim’ (34,6 t/ha), and F1 ‘RD 96 2-95’/ ‘Dzherelo’ (34.2 t/ha). The selected hybrids yielded significantly more than the check F1 hybrid ‘Ajax’ (by 80-142 % or by 19.0 t/ha).