Comparison of three testing methods for evaluation of resistance to red rot caused by Colletotrichum falcatum in sugarcane (Saccharum officinarum)

Abstract

Red rot, caused by Colletotrichum falcatum Went is one of the major diseases of sugarcane (Saccharum officinarum
L.) affecting cane stalks. Sugarcane genotypes are tested using both plug and nodal evaluation methods for resistance
against red-rot pathogen, before varietal release. These recommended testing methods were compared with the newly
developed controlled condition testing procedure. Red-rot was evaluated during 1992-93, 1993-94 and 1994-95 seasons
under field conditions and controlled condition testing. Disease ratings of the pre-zonal varietal trial clones by 3
different testing procedures showed that the controlled conditions testing had high correlation with plug method compared
with the nodal method of evaluation in the field. Testing by controlled condition testing gave more reliable
results than field nodal method and many disease escapes noticed in the latter were identified. Plug method of evaluation
also showed less correlation with nodal method. Controlled condition testing was found less injurious and evaluation
could be done in a more natural way. Among the 3 methods controlled condition testing was suitable to indentify
field tolerant clones with more reliability in a short time.