Formation of leaf surface area, photosynthetic potential and yield of cucumber hybrids under drip irrigation in the Southern Steppe of Ukraine

Abstract

Purpose. The purpose of the study is to establish theregularities of the formation of the leaf surface area, photosyntheticpotential, the utilization rate of the leaf apparatus,and the yield of hybrids of Kibria F1 and MadeiraF1 cucumbers depending on the use of biopreparationsand microfertilizers under drip irrigation in the conditionsof the Southern Steppe of Ukraine, as well as to substantiatethe feasibility of combining these elements of growingtechnology in growing seasons with different levels ofmoisture. Methods. The field experiment was conducted atthe Educational-Scientific-Practical Center of the MykolaivNational Agrarian University according to a four-factorscheme: cucumber hybrid, biopreparation, microfertilizerand fruit harvesting mode. The research was carried outunder drip irrigation. The area of the leaf surface was determinedby the calculation-weight method, the photosyntheticpotential and the coefficient of use of the leaf surface – bythe calculation method. The yield was calculated accordingto commodity standards, and the relationships betweenthe studied characteristics were evaluated using correlationanalysis methods. The coefficient of climatic sensitivitywas used to determine the dependence of the leaf surfacearea on weather conditions. The results. The article presentsthe results of three-year (2023–2025) field researchon the study of patterns of formation of the assimilationapparatus and productivity of two parthenocarpic cucumber hybrids (Kibria F1 and Madeira F1) under drip irrigation inthe Southern Steppe zone of Ukraine. It was establishedthat the size of the leaf surface is determined mainly bythe weather background of the vegetation: between thefavorable 2023 and the dry 2024, the difference reached54.2%, while the contribution of the nutrition system did notexceed 12–13%. An inverse relationship was establishedbetween the area of the leaf apparatus and the efficiencyof its use: with optimal moisture, part of the assimilates wasspent on vegetative growth, reducing the specific yield ofleaves. Madeira F1 hybrid with 5–8% smaller leaf surfacearea was superior to Kibria F1 hybrid in its utilization ratioby 16–22% and yield by 12.9%. The combination of OrganicBalance with Quantum PLATINUM provided the highestindicators of all the studied signs. The obtained data justifythe selection of the hybrid and nutrients for the sustainableproduction of cucumber in conditions of aridization of theclimate. Conclusions. The formation of the cucumber leafsurface area in the open ground was largely determined bythe hydrothermal conditions of the growing season, whilethe efficiency of its use depended on the characteristicsof the hybrid and the applied elements of the technology.The Madeira F1 hybrid, forming a smaller area of the leafapparatus, was characterized by a higher efficiency of itsuse compared to Kibria F1. The combination of OrganicBalance biological preparation and Quantum PLATINUMmicrofertilizer improved the functioning of the leaf apparatusand increased yield, especially under dry conditions. Thehighest average yield (46.79 t/ha) was provided by thecultivation of the Madeira F1 hybrid with the complex useof the specified drugs. Photosynthetic potential was characterizedby a close positive relationship with productivity(r = 0.91–0.96), which confirms its informativeness as anindicator of the productivity of cucumber crops.