Cocoon Filament Production of Bivoltine Silkworm Hybrids Heritability

Abstract

Heritability of cocoon filament production in bivoltine silkworm hybrids was studied using full diallel crossed among PH2, PH3, PH5, PH8, PH9 and PH10. Thirty selected silkworm hybrids and 6 parental lines were assigned in the randomized complete block design with 10 replications. Genetic analysis was done using Griffing (1956) method 1 model 2 and broad and narrow sense heritability. Three consecutive experiments were conducted at Chiang Mai Sericultural Experiment Station in three periods: August 1996, November 1996 and March 1997. Low heritability was found among three experimental periods. Broad sense heritability of length cocoon filament, weight cocoon filament and size cocoon filament in period I, II and III was 19.99-23.08, 7.94-23.08 and 0.70-12.02 percent, respectively, and narrow sense heritability was 2.13-15.39, 6.20-8.32 and 0.70-12.02 percent, respectively. Therefore, environmental factors such as rearing technique, temperature, humidity, mulberry leaves, cocoon drying, cocoon cooking and silk reeling might have influenced to phenotype of cocoon filaments.