ABSTRACT.


FERNANDO MUJICA R.1
 

A1though bean anthraenose (Colletotriehum lindemuthianum) is prevalent only in eertain loealized regions of the country, such as Mallarauco, La Cruz, Quillota, Boca, an Limache, it constitutes in these areas one of the most serious diseases of this crop.
A knowledge of physiological races of the pathogen involved and the reaction of the Chilean varieties to their attack must precede the formulation of any plant breeding project.
In an investigation of this preliminary phase of such a project, three strains of the fungus - named according to their origin, Boco, Mallarauco and Santiago - were isolated and were used to inoculate 25 domestic and introduced bean varieties, as well as groups of differential or knpown-reaction varieties.
The reaction of the tested varieties to the three isolates of the pathogen seemed to indicate that only one, native race of the fungus was involved, distinct from its known α β and ϒ races. As these isolates were taken from the sections of Chile where the disease is most important, it is permissible to conclude that only one physiological race of bean anthracnose exists in our country. However, it will still be necessary to prove its identity with the pathogen responsible for sporadic attacks in La Serena in the north and Angol al1d Contulmo in the south.
The domestic bean varieties, Arroz and Cristal, and the introduced varieties, Red Kidney and Michelite, are immune or highly resistant to this native race of anthracnose and may contribute with factors for disease resistance which can be employed in breeding programs to improve susceptíble commercial varieties preferred by Chileans.

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1 Ingeniero Agronómo, Jefe de la Sección Fitopatología del Departamento de Investigaciones Agrícolas.