A Major Recessive Gene Associated with Anthracnose (Colletotrichum capsici) Resistance in Chilli Pepper

Abstract

Chilli anthracnose caused by Colletotrichum sp., is an important disease in Bangladesh and many other Asian countries. Recently the local Bangladeshi genotype ‘Comilla-2’ was found resistant to C. capsici. Inheritance of resistant to C. capsici was analyzed in segregating populations derived from a cross of ‘BARI chilli-1’ x ‘Comilla-2’. BARI chilli-1 as susceptible and Comilla-2 as resistant parent was used in the study. Detached matured green fruits were inoculated using the microinjection method. Disease response was evaluated using disease incidence and over all lesion diameter at 8 days after inoculation. The disease reaction of F1 plants in case of disease incidence and overall lesion diameter were clearly skewed to the susceptible parent, with average values of 46.70% and 13.2 mm, respectively. The distribution of disease incidence in the F2 population was skewed toward the susceptible parent and the distribution of overall lesion diameter in the F2 population showed a similar trend. Based on the scale of resistance and susceptibility, less than 25.0% disease incidence or less than 9.0 mm overall lesion diameter were evaluated as resistance. In the cross ‘BARI chilli-1’ x ‘Comilla-2’, the segregation ratios of resistance and susceptibility scored by disease incidence and overall lesion diameter in the F2 , BCr and BCs populations and chi-squared test significantly fitted one recessive gene model i.e. 1:3 Mendelian model. The result indicates that the resistance of ‘Comilla-2’ to C. capsici is controlled by a single recessive gene.