Studies on triploid oysters in Australia XIII.: Performance of diploid and triploid Sydney rock oyster, Saccostrea glomerata (Gould, 1850), progeny from a third generation breeding line

The performance of diploid and triploid selected and control oysters was compared at three sites to determine if the improvements in growth of selected oyster line (L2) Sydney rock oysters were additive to the faster growth of triploids. After a grow-out period of 32 months, both mean whole weights and shell heights were in the order: L2 triploids>control triploids>L2 diploids>control diploids. Mean whole weights of different oyster lines were all significantly different (p < 0.05). A significant (p = 0.02) site x line interaction effect on oyster weights was also detected. On average, L2 triploids were 74% heavier than control diploids, indicating that growth improvements from selective breeding and triploidy were at least additive and could reduce the time to market by at least 10 months. Oyster type had no effect on the meat condition index, percent cavity volume, percent shell weight or cumulative mortality, but did affect whole weight/shell height ratios after 21 months grow-out. (C) 2004 Elsevier B.V. All rights reserved.