New strawberry breeding lines with low susceptibility to anthracnose in southwestern Spanish conditions

Anthracnose caused by Colletotrichum acutatum is one of the major fungal diseases of strawberry occurring worldwide. This pathogen causes black spot on fruit, root necrosis and crown rot resulting in mortality of transplants in the field. In addition, lesions are formed on petioles and stolons, limiting production of strawberry plants in nurseries. Breeding programs for resistance to this disease are in progress in Spain adapted to local conditions. In the present work, 6 cultivars and 2 breeding lines were included in assays of susceptibility with artificial inoculation. Eighteen plants of each cultivar were inoculated spraying a conidial suspension of C. acutatum. After inoculation, plants were cultivated in a growth chamber in a randomized design with three repetitions of six plants each. The assays were conducted twice from September to October in 2018 and 2019. Results showed 4 susceptibility groups: ' Florida Brilliance' was the most resistant cultivar, followed by the breeding line A14-205P-5 and 'Rabida FNM'. In the third group and significantly similar to 'Rabida FNM' appeared the breeding line A14, 'Rosa Linda', 'Rociera FNM' and 'Festival' with moderate susceptibility. The most susceptible cultivar was 'Primoris FNM'. A14-205P-5 had 54.9% less disease severity than the most susceptible cultivar in the average of the two years. Therefore, selection of resistant cultivars adapted to these local conditions are presenting promising results to control anthracnose.