Allelopathic Effects of Juglone and Walnut Leaf and Fruit Hull Extracts on Seed Germination and Seedling Growth in Muskmelon and Cucumber

Abstract

In this study, effects of the extracts of walnut fruit hulls and leaves on muskmelon (Cucumis melo cv. Galia) and cucumber (Cucumis sativus cv. Beith Alpha) seed germination percentage and post-germination seedling growth were investigated. Extracts were obtained by homogenization and centrifugation from walnut fruit hulls and leaves. Muskmelon and cucumber seeds were germinated in Petri dishes at 25 ºC. Seeds germination rates, seedling elongation and dry weights were determined at day 10. In conclusion, no significant effect of walnut extracts on muskmelon and cucumber seed germination percentage was determined. However, cucumber germination percentage was affected negatively by 1/4 walnut leaf extract and all juglone treatments. While the 1/4 diluted walnut fruit hull extract and 1/8 diluted walnut leaf extract increased root and stem growth of muskmelon seedlings, both walnut fruit hull and leaf extracts decreased root and stem growth of cucumber.