OPTIMIZING WATER USE FOR DRY-SEASON CUCUMBER (Cucumis sativus L.) PRODUCTION: EFFECTS OF REGULATED DEFICIT IRRIGATION AND CULTIVAR SELECTION IN THE NORTHERN GUINEA SAVANNA OF NIGERIA

Field experiment was conducted during the 2020 and 2021 dry seasons at the Federal College of Forestry, Jos, to assess the response of two cucumber cultivars (Poinsett and Marketer) to deficit irrigation regimes in the Northern Guinea Savanna of Nigeria. Treatments consisted of four irrigation schedules (control, 4–6, 5–7, and 7–9 weeks after sowing) and two cultivars (poinsett and marketer). These were laid in a split-plot design with irrigation schedules as main plots and cultivars as subplots. These were replicated three times. Results of the study revealed that moderate deficit irrigation (4–6 WAS) did not significantly reduce key growth parameters such as leaf number, vine length, and branching compared to the control. However, severe deficit irrigation (5–7 and 7–9 WAS) significantly reduced fruit diameter, length, number of fruits per plant, and overall yield (p < 0.001). The Marketer consistently recorded higher yields (10,511 kg/ha) than Poinsett (9,122 kg/ha). Days to 50% flowering and first fruiting were also significantly delayed under severe deficit irrigation. The study concludes that combining regulated deficit irrigation (4–6 WAS) with the Marketer cultivar offers a promising strategy for improving water use efficiency and sustaining cucumber yield in semi-arid environments.