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.

The reaction of pepper breeding lines under organic production conditions to Verticillium wilt, viruses and phytoplasma was observed at Maritsa Vegetable Crop Research Institute, Plovdiv, Bulgaria during two successive years. The diseases severity was recorded, when symptoms of Verticillium dahliae, viruses and Phytoplasma diseases were deeply expressed. The Verticillium dahliae attack index for early production breeding lines varied widely from 15.04% for line O58/14 to 43.83% for O26/16. For kapia type materials, the attack rate of Verticillium wilt ranged from 39.27% (O17/15) to 46.68% (O79/16). The highest index of attack by the disease was established for the powder breeding line (OP69/16) – 49.85%. The viruses which were monitored belong to groups of tobamoviruses, cucumoviruses and tospoviruses and were only 5.00% in breeding lines for early production. The Phytoplasma development was from 10.51% (O12/15) to 32.92% (O38/14). It was established that among studied diseases Verticillium wilt (42.41%) was more dangerous for studied pepper breeding lines in organic conditions followed by Phytoplasma disease (20.67%) and viruses (0.59%).

Study was carried out for determining the reaction of 83 peppers varieties, breeding lines, and local forms /landraces/ to fungal pathogen Verticillium dahliae Kleb. as they are the part of the Balkan Capsicum core collection which was deeply phenotyped in the recent years. The development of the disease was reported twice and high degree of resistance was reported for 41 accessions. The highest percentage of highly resistant group of genotypes was 72%, followed by resistant group with 23%. The infestation in the groups of medium sensitive, sensitive and highly sensitive was respectively 1%, 3%, and 1%. The highly sensitive (0 - 19%), sensitive (20 - 39%) and medium sensitive (40 - 59%) are consisted by the var. blocky, var. ratundum and var. kapia accessions. The group of resistant (60 - 79%) was dominated by var. ratundum and var. blocky. Materials from var. kapia prevail of highly resistant (80 - 100%). The group of pungent peppers accessions was more resistant to Verticillium infestation. On the base of current and previous results may concluded that four accessions were identified as resistant to TMV and non-infested by Verticillium while two ones possessed low infestation by green aphids, trips and cotton bollworm and non-attacked by Verticillium. Other seven genotypes combined lack of infestation by Verticillium wilt with high levels of three and more agronomic and biochemical traits.