Published in Scientific Papers. Series B, Horticulture, Vol. LXIV, Issue 1
Written by Marieta NESHEVA, Diyana ALEXANDROVA, Valentina BOZHKOVA
Apricot decline remains an important threat to the apricot industry. Pathogens like: fungi, bacteria, viruses and mycoplasma are able to destroy the trees after several years of good growth. Diseases caused by Pseudomonas spp. in apricot has widely spread in fruit-producing areas worldwide. During the 2018 growing period, isolations were taken from apricot trees showing “blossom blast” symptom, grown in an apricot breeding orchard at the Fruit Growing Institute of Plovdiv, Bulgaria. It was found that in this area the species causing the observed symptom belong to Pseudomonas spp. In terms of integrated pest management genetical resistance of the cultivars is the most reliable way for reducing infection. In 2019, thirty-one apricot elites, selected from the hybrid families 'Harlayne’ x 'Harcot’, 'Lito’ x 'Silistrenska ranna’ and 'Harcot’ x 'SEO’ and all parental cultivars, were tested for their response to Pseudomonas spp. infection after artificial inoculation. The aim of this experiment was to study the reaction of all elites to the pathogen and to select the perspective ones for future breeding purposes. The laboratory tests were conducted in 2019 by artificial inoculation of one-year-old shoots in 'full flowering’ phenophase with the obtained in 2018 isolate of the phytopathogen. In 48% of the studied elites, first symptoms were observed on the second day after the inoculation. Twenty-nine percent of the elites showed the first symptoms on the 5th day after inoculation. The parental cultivar Silistrenska ranna was the only genotype that showed symptoms on the 6th day. The lowest disease severity index was recorded for elite LS 14-30 – 3,45%, followed by HH 13-45 13,68%, HH 9-2- 15%, HH 13-20 - 15,43% and HH 9-1 - 17,50%. which makes them valuable for future breeding purposes.
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