Estimates of genetic parameters related to chitinase production by the entomopathogenic fungus Metarhizium anisopliae

Abstract

Chitinolytic activity and dry mass production were determined in culture filtrates from 17 Metarhizium anisopliae strains grown in liquid medium containing chitin as the only carbon source. The objectives were to estimate parameters such as genetic variance among strains, heritability and expected gain from selection, as well as correlations between tested traits. Wide genotypic variability was observed among strains in chitinolytic activity, permitting the exploitation of this property in selection. The high heritability suggests that progress can be made through phenotypic selection. The genotypic correlation coefficient between dry mass production and chitinolytic activity detected in the filtrates was negative (r(G) = -0.588). One of the isolates was also investigated for variation in the two traits as a function of culture growth time. The results showed an increase in enzyme activity up to the 8th (and last) day of the experiment and a decrease in dry mass from the 4th day on.