<b>Classification of <i>Colletotrichum lindemuthianum</i> races in differential cultivars of common bean

Abstract

ABSTRACT. Anthracnose caused by the fungus Colletotrichum lindemuthianum is one of the main diseases affecting the common bean (Phaseolus vulgaris L.), and the pathogen is characterized by wide variability, with more than 50 physiological races identified in Brazil. Greater occurrences of races 65, 73, and 81 have been observed in Brazil along with the occurrence of pathogenic variability among isolates of a single race, destabilizing the resistance of commercial cultivars. Therefore, the aim of this study was to identify physiological races of C. lindemuthianum isolates collected in the states of São Paulo and Santa Catarina, Brazil and to test for variability among the isolates of race 65. The classification of 51 isolates resulted in the identification of 10 different physiological races: 4, 38, 55, 65, 73, 81, 83, 85, 321, and 351. Races 65 and 81 predominated, with frequencies of 37.25 and 35.29%, respectively. Regarding the isolates of race 65, wide physiological variability was evident, suggesting that a new differential set should be applied to detect the levels of variation among isolates of a single race of the pathogen.Keywords: physiological variability, levels of variation, anthracnose. Classificação de raças de Colletotrichum lindemuthianum em cultivares diferenciadoras de feijoeiro comum RESUMO.A antracnose causada pelo fungo Colletotrichum lindemuthianum é uma das principais doenças do feijoeiro comum (Phaseolus vulgaris L.), o patógeno caracteriza-se por apresentar uma grande variabilidade, com mais de 50 raças fisiológicas identificadas no Brasil. Tem-se evidenciado a maior ocorrência das raças 65, 73 e 81 no país e também a ocorrência de variabilidade patogênica entre isolados de uma mesma raça, que desestabilizam a resistência das cultivares comerciais. Portanto, o objetivo com este trabalho foi a identificação de raças fisiológicas de isolados de C. lindemuthianum coletados no Estado de São Paulo e Santa Catarina, Brasil e, detectar a ocorrência de variabilidade patogênica entre isolados pertencentes à raça 65. A classificação de 51 isolados resultou na identificação de 10 diferentes raças fisiológica: 4, 38, 55, 65, 73, 81, 83, 85, 321 e 351, com destaque para a raças 65 e 81, que apresentaram uma frequência de 37,25 e 35,29%, respectivamente. Com relação à avaliação entre os isolados da raça 65, ficou evidente a alta variabilidade dos mesmos, sugerindo a utilização de um novo conjunto diferenciador para detectar os níveis de variação entre isolados de uma mesma raça do patógeno.Palavras-chaves: variabilidade fisiológica, níveis de variação, antracnose.

Selection of common bean lines obtained by the genealogical and bulk methods for disease resistance and agronomic traits

“…Zuiderveen et al (2016) evaluated 230 common bean lines for eight races of the pathogen (7, 39, 55, 65, 73, 109, 2047, and 3481) and indicated 12% resistance to six races and only one cultivar resistant to all the races evaluated. In the present study, 39% resistance to races 31, 65, and 81 of the pathogen was observed; however, the wide variability and the different levels of aggressiveness of the races found in the main common bean production regions in Brazil require a constant search for resistant cultivars in breeding programs (Ribeiro et al, 2016), reinforcing the importance of the present study.…”

“…These results were expected because these lines originated from crosses made with 'IAC Una' and 'IAC Diplomata', resistant to the main physiological races already identified in Brazil (Chiorato et al, 2015). It should be noted that anthracnose is one of the main diseases that affect common bean and, according to Ribeiro et al (2016), 10 races of the pathogen have been identified in the state of São Paulo, with races 65 and 81 occurring most frequently. Furthermore, the authors emphasized the high physiological variability among the isolates of race 65 of the pathogen, which shows the importance of using resistant cultivars to maintain the yield and seed quality of common bean.…”

Research Article Selection of resistance sources to common bean anthracnose by field phenotyping and DNA marker-assisted screening

“…However, the wide variability of C. lindemuthianum is a challenge for the common bean breeders. In Brazil, dozens of physiological races of the anthracnose pathogen have already been identified and described (Rava et al, 1994;Balardin et al, 1997;Carbonell et al, 1999;Alzate-Marin and Sartorato, 2004;Ribeiro et al, 2016). Genetic and physiological diversity have also been reported among C. lindemuthianum isolates belonging to the same race (Davide et al, 2009;Ishikawa et al, 2011).…”

Genetic Variation of Landraces of Common Bean Varying for Seed Coat Glossiness and Disease Resistance: Valuable Resources for Conservation and Breeding

“…Seeds of each parental line (SAB and SAF) and control standards from the literature (cultivars Rosinha G2 and G2333 are highly susceptible and resistant, respectively) were germinated and transferred to pots with substrate (Plantmax) in a greenhouse, and irrigated properly until the establishment of the first trifoliate (around 21 days). One leaf was collected from each plant and immediately placed in a suspension of 1.2 × 10 6 conidia mL −1 of C. lindemuthianum races 65 and 73 [39]. After 1 min, the leaves were placed in Petri dishes containing two layers of moistened filter paper.…”