LONG-TERM SELECTION FOR A QUANTITATIVE TRAIT IN TRIBOLIUM-CASTANEUM .1. RESPONSE TO SELECTION

An experiment with the flour beetle Tribolium castaneum was carried ou r to study the long-term response ro selection for pupal weight, for a period of 20 generation. Three population sizes (10, 20 and 40 pairs of parents) and three proportions selected (10%, 20% and 30%) were con sidered along with a control for each population size. The experiment was replicated twice. The response, in general, was maximum in lines u nder 10% selection, followed by 20% and 30%. The population size 40 wa s superior to 10 and 20. The performance of controls was stable throug hout the experiment. The responses predicted using conventional approa ch were much higher than the observed values.