An investigation on heterosis and inbreeding Depression in the silkworm (Bombyx mori L.) ud

摘要

The aim of this study was to define heterosis and inbreeding depression in the four silkworm (Bombyx mori L.) udraces namely C108, NB4D2, Pure Mysore and Nistari for four important characters including larval weight, cocoon weight, udshell weight and shell percentage. The traits of larval weight and cocoon weight showed highly significant heterosis in F1 udhybrids ranging from 11 to 23% and 14 to 27 % respectively, while inbreeding depression in the F2 progeny ranged from -ud0.366 - 10.814% and 2.682 - 12.312% respectively. Shell weight showed low level of heterosis in F1 hybrids (14 to 20 %), udwhereas the effect of inbreeding depression in F2 progeny was -4.369 to 8.467% for this character. C108 × NB4D2 hybrids udproved to be a good specific combiner by making higher contribution towards heterosis both in F1 hybrids and inbreeding udat F2 generation. ud