Abstract
<title>Abstract</title> <p>The increasing scarcity of freshwater resources driven by climate change has compelled farmers in many parts of Nigeria to rely on alternative water sources such as groundwater and lower-course streams for dry-season irrigation. These sources frequently carry elevated salt concentrations that can suppress crop growth and reduce yield. This study evaluated the response of hybrid cucumber (Cucumis sativus L., variety Daewy F1) to five levels of irrigation water salinity under screen house conditions at the Federal University of Agriculture, Abeokuta. The experiment was arranged in a Completely Randomized Design (CRD) with five treatments and three replicates. Treatments consisted of irrigation water prepared at electrical conductivity (EC) levels of 0.00 dS/m (T1, non-saline control), 1.50 dS/m (T2), 2.50 dS/m (T3), 3.50 dS/m (T4), and 5.00 dS/m (T5), using sodium chloride (NaCl) as the salt source. Data were collected on microclimatic conditions, growth parameters (soil temperature, vine length, leaf area, leaf length, leaf breadth, and number of leaves), and yield characteristics (number of fruits, fruit length, fruit weight, and fruit diameter). Results showed that all growth and yield parameters declined progressively with increasing salinity. T2 (1.50 dS/m) produced results comparable to T1 across all yield parameters, while T3 (2.50 dS/m) produced a more than 50% reduction in fruit number relative to T1. T5 (5.00 dS/m) resulted in complete plant death by Week 7 with zero yield recorded. It is concluded that Daewy F1 cucumber can tolerate irrigation water salinity of up to 1.50 dS/m without significant production loss, while 2.50 dS/m represents the practical threshold beyond which economically significant losses occur under screen house conditions in Abeokuta.</p>