Plant performance and physiological changes of some bedding zinnia cultivars on restricted irrigation conditions

Zinnia is an ornamental plant used as a cut flower, potted plant and mainly as a bedding plant for outdoors. In this study, plant stress responses and tolerance level of zinnia against limited irrigation conditions were revealed. In the study, growth and development, visual quality, and water status plant characteristics were investigated in nineteen zinnia cultivars belonging to two Zinnia species (Zinnia elegans L. ve Zinnia marylandica SSB.) and four different cultivar series (Dreamland, Zesty, Double Zahara ve Zahara) under three different irrigation regimes (%75, 50 ve 25). The decrease in irrigation quantity was accompanied by some losses in terms of stem length, internode length, stem diameter, number and size of leaves, root and shoot dry weights, L (blackness-whiteness), C (opacity-vividness), hue (colour angle), compactness, visual symptom scale, leaf relative water content, and shoot moisture content. Adversely effects that emerged in terms of parameters evaluated in the study, compared to control (75%) with restricted irrigation regime treatments, were more clearly seen in the severely restricted irrigation regime (25%) than in the moderately restricted irrigation regime (50%). The zinnia cultivars evaluated in the study demonstrate a wide performance range, between high and low levels, depending on the limited irrigation regime practices. Zahara Fire and Double Zahara Yellow as tolerant cultivars and Dreamland Rose and Zahara Cherry as sensitive cultivars were seen for restricted irrigation treatments. As a result, in the study, some findings that can serve to the water scarcity situation management due to global climate change, which the world is facing, were obtained.