0971-4693/94 Euro 20.00 Allelopathy Journal 44 (2): __-__ (May, 2018) International Allelopathy Foundation 2018 Table: 3, Figs : 3 Screening of 239 Paraguayan plant species for allelopathic activity using the sandwich method T. Nakamori-Maehara, R. Miyaura1*, C.I.O. Morikawa2, L.F. Pérez de Molas3 and Y. Fujii4 Department of International Biobusiness Studies, Graduate School of Agriculture, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan. E, Mail:
[email protected] (Received in revised form: May 25, 2018 ) ABSTRACT We evaluated the allelopathic potential of 239 Paraguayan plants using the sandwich method. The samples were collected from 3-different regions of Paraguay. A total of 130 species, 47 families were collected from (i). Botanical Garden and Zoo of Asunción and its surroundings, (ii). 71 species (40 families) from Mbaracayú Natural Reserve and (iii). 38 species (25 families) from the Chaco region. We found the species with high inhibitory potential, such as Cleome aculeata (Cleomaceae), which completely inhibited the germination of lettuce. Others spp. strongly inhibited the growth of lettuce seedlings viz., Strychnos brasiliensis (Loganiaceae), Pterogyne nitens (Fabaceae), Sorocea bonplandii (Moraceae), Rollinia emarginata (Annonaceae), Microstachys hispida (Euphorbiaceae), Prosopis ruscifolia (Fabaceae) and Senna sp. (Fabaceae). These results demonstrated high allelopathic potential of Paraguayan plant species. Key words: Allelopathy, Cleome aculeata, germination, lettuce, Paraguayan plants, Pterogyne nitens, sandwich method, seedling growth, Sorocea bonplandii, Strychnos brasiliensis. INTRODUCTION South America has rich biodiversity and is the centre of origin of several cultivated plants (19,47). Paraguay, also called “the heart of South America” due to its geographical location, also has rich flora and fauna (24,44).