Selection of Elms Tolerant to Dutch Elm Disease in South-West Romania

Ophiostoma novo-ulmi continues to be one of the most dangerous invasive fungi, destroying many autochthonous elm forests and cultures throughout world. Searching for natural genotypes tolerant Dutch disease (DED) is main objectives silviculturists all over northern hemisphere in order save susceptible elms restore their ecosystem biodiversity. In this regard, first trial was established between 1991 1994, south-west Romania (Pădurea Verde, Timișoara), using three species (Ulmus minor, U. glabra, laevis) with 38 provenances. A local strain used artificially inoculate variants DED evolution observed. Furthermore, 2018–2021 inventoried understand genotype reaction environmental conditions after almost 30 years. The outcomes present study proved continuous presence infections comparative culture its proximity, but identified pathogen had a new hybrid form (found time Romania) O. ssp. americana x novo-ulmi. Wych (U. glabra) extremely sensitive DED: only 12 trees (out 69 found 2018) survived 2021, tree could selected according adopted health criteria (resistance vigour). field minor) pathogen, there were still individuals that showed good status growth. contrast, European white constant tolerance 15% been dead or presented severe symptoms dieback. Overall, results report diverse reactions Romanian regional last decades, providing promising perspectives improving forest ecosystems Carpathian basin.