DIVERGENT SELECTION FOR EGG NUMBER IN TRIBOLIUM-CASTANEUM .2. CORRELATED RESPONSES IN HATCHABILITY, PUPATION TIME AND ADULT EMERGENCE TIME

Two-way family selection for 8-10 day total egg number (TEN) at 33.33 and 50.00% selection intensities for 7 generations was practised in Tr ibolium castaneum. Its correlated responses in unselected traits, viz. hatchability, pupation time (PT) and adult emergence time (AT), were studied with the help of a contemporaneous control line. The estimates of heritability obtained from dam components were higher than that fr om sire + dam components followed by sire components in all the 3 unse lected traits. The base population and the control line showed almost similar trend. In general, the magnitude of heritabilities for the dif ferent traits was moderately high. The genetic and phenotypic correlat ions between TEN and hatchability were positive and of moderately high magnitude, whereas the values for TEN with PT and AT were negative an d of high magnitude in the base population, selected and control lines . The average hatchability percentage increased by 1.61 and 1.49 in th e HS1 and HS2 lines respectively. It decreased by 0.41 and 0.44 in the LS1 and LS2 lines respectively. There was a shortening of PT by 0.44 day in each of the high selected line, whereas a lengthening of the pe riod by 0.25 and 0.26 day only observed in the low selected lines. LS1 and LS2, respectively, after 7 generations of selection. Almost simil ar trend was recorded in AT with respect to its shortening and lengthe ning. There was a poor agreement between the ratio of observed and exp ected correlated responses for all the traits.