• Energy Research

During the past 40 years in Bulgaria a change has been observed in the cultivar composition and reduction of the total vineyards from 200,000 ha in 1980 to 63,647 ha in 2020. Climate change and the introduction of more disease-resistant grape cultivars have led to the threat of extinction of traditional old local cultivars such as ‘Ribi mekhur’, ‘Lisicha opashka’, ‘Orlovi nokti’, ‘Chaush’, ‘Keratsuda’, etc., through which the country has built market positions in a number of countries. In the present study, some old local cultivars threatened with extinction have been mapped and recommendations for their restoration in Bulgaria have been given.

AbstractProfessional and scientific networks built around the production of sweet cherry (Prunus avium L.) led to the collection of phenology data for a wide range of cultivars grown in experimental sites characterized by highly contrasted climatic conditions. We present a dataset of flowering and maturity dates, recorded each year for one tree when available, or the average of several trees for each cultivar, over a period of 37 years (1978–2015). Such a dataset is extremely valuable for characterizing the phenological response to climate change, and the plasticity of the different cultivars’ behaviour under different environmental conditions. In addition, this dataset will support the development of predictive models for sweet cherry phenology exploitable at the continental scale, and will help anticipate breeding strategies in order to maintain and improve sweet cherry production in Europe.

In the conditions of global climate change and invasion of new diseases and pests, the utilisation of the local gene pool is a vital step towards sustainable agriculture. Local cultivars and forms are generally considered as better adapted to the conditions of the originating region than widely spread commercial cultivars bred elsewhere. In order to collect, study, and preserve old and local fruit and vine cultivars and forms, a series of expeditions have been conducted throughout Bulgaria under the frame of project KP-06-N46/3 funded by the National Science Fund of the Bulgarian Ministry of Education and Science. During these scientific expeditions, several local cherry forms were discovered without visual symptoms of brown rot Monilinia laxa (Aderh. and Ruhl.) Honey or cherry leaf spot Blumeriella jaapii (Rehm) Arx. To confirm the degree of resistance/low susceptibility of the specimens, laboratory tests with artificial inoculations of fruits and leaves were conducted. In the current study, two specimens found in Damyanovo region (a village in the municipality of Sevlievo, Gabrovo Province, in northern central Bulgaria) were included. They were compared to two old local cherry cultivars, ‘Volsko sartse’ and ‘Ranna cherna edra’, and two new selections of FGI-Plovdiv, ‘Asparukh’ (El.17-90) and ‘Kossara’, using ‘Bigarreau Burlat’ as reference cultivar for resistance to economically important diseases. The artificial inoculations confirmed the field observation of the cherry specimen with designation SM-58 with 0.00% of infected fruits. Therefore, it is recommended for use in the breeding programme of the Fruit Growing Institute, Plovdiv for the creation of new cultivars.