Обзор върху антракнозата по фасула (Colletotrichum lindemuthianum) в Бъргария

Abstract

Bean anthracnose, caused by Colletotrichum lindemuthianum, is a key disease in a number of countries around the world. Depending on the varietal structure and climatic conditions, yield losses vary from 10-58% to the complete destruction of crops. For the conditions of Bulgaria, the disease has a sporadic character in the plain areas, but in the mountainous areas it occurs annually. The pathogen control is related to uninfected seed material, long crop rotation, destruction of plant residues, application of fungicides and use of resistant varieties. C. lindemuthianum is characterized by considerable virulence diversity, which makes it difficult to breeding resistant cultivars and leads to overcoming already achieved resistance. This publication summarizes research on the virulence diversity of C. lindemuthianum in Bulgaria over the last forty years. In parallel, data on the resistance of Bulgarian dry bean varieties, some of which are essential for production in the country, to a set of physiological races of C. lindemuthianum are summarized. The analysis of the identified races shows significant virulence diversity in the pathogenic populations in Bulgaria. During the period 1979-2006, 10 physiological races were identified - 2, 3, 6, 22, 23, 54, 73, 79, 81 and 131. Race 81 was dominantly prevalent (78.4% of isolates) in traditional dry bean growing areas in the country. Races 2, 6, 22, 54 and 131 are established in the Rhodopе Mountains and Pirin Mountains. Races 3, 23, 73 and 79 were incidental to Bulgaria and there is no confirmation of their distribution. Of the 17 varieties presented in the overview, resistance to 11 races of C. lindemuthianum has variety Pukliv 1. Variety GTB Blyan is susceptible to races 6 and 81 and resistant to the remaining 9 physiological races included in the test. The Pirina variety is resistant to 10 of the 11 races tested. The varieties Pukliv 1, Trakya and Pirina are resistant to race 81, which prevails in Bulgaria. All cultivars have resistance to one or more of the investigated physiological races, which makes it possible to include them as resistance donors in the breeding of dry beans, by the pyramidal accumulation of race-specific genes.