Water for Agricultural purposes is increasingly becoming limited owing to global climatic change and increased demand from other uses such as household water users, industries, and the environment. Tomato is an herbaceous crop that needs an adequate amount of water for growth and yield optimization. This experiment was conducted in pots in a greenhouse to examine the effect of water stress on the growth, yield, and shelf-life of five tomato varieties namely Padma F1, Cobra F1, Symbal F1, Titanium F1, and Nkansah GH. This study aimed to differentiate and identify the best soil field capacity for good plant growth and optimization of yield. This research was conducted at the project site of the NEIP Envirodome greenhouse at the Dawhenya irrigation scheme in Ghana, from January 2017 to May 2019 for 5 cropping cycles. The tomato varieties were subjected to soil field capacity of 80-100FC%, 70-75FC%, 60-65FC%, 50-55FC% with three replications in a randomized complete block design. Plant height, Stem diameter, Internode length, Leaf Relative Water Content, Stomata Conductance, Transpiration rate, yield, and shelf-life were the parameters measured to compute the effect of water stress on the different tomato varieties. Results from this study revealed that water stress decreased significantly Leaf Relative Water Content, Stomata Conductance, and Transpiration rate at p<0.05. Plants subjected to high water stress, i.e. 50-55FC%, however, revealed an average of 21.1% reduction in plant height, 19.4% decrease in stem diameter, and 35.4% decrease in internode length. Furthermore, water stress decreased plant yield for all five varieties due to flower abortion and fruit dropping. Shelf-life and total soluble salts increased with plant water stress. Even though there was no significant difference among the five varieties at the same soil water content, analyzing each variety at different soil water content and comparing % reduction in terms of plant height (Ph), Stem diameter (DS), and Internode length (LI) revealed that Nkansah GH recorded the highest % growth reduction in terms of plant height and stem diameter by 24.13% and 21.11%, whereas Cobra F1 recorded the highest reduction in internode length of 40.54%. In conclusion, moderate water stress at field capacity 60-65 FC% resulted in optimizing plant morphological characteristics, physiological response, yield, shelf-life, and total soluble salt.
Keywords: water stress, tomato, crop physiology, crop morphology, yield, stomatal conductance, transpiration rate, relative leaf water content.