Tetrapoid Pacific oysters have been used for production of 100% triploids for four years, with production doubling almost every year. To expand the market 100% triploids worldwide, cryopreserved tetraploid germ plasm offers the most viable strategy. This proposal is intended to capitalize on the combined successes of tetraploid technology that have been developed by Taylor Resources, Inc. and 4Cs Breeding Technologies, Inc., and of the recent successes in cryopreservation obtained with C. virginica at Louisiana State University Agricultural Center. Development of successful procedures for tetraploid sperm will enable immediate commercialization and make possible worldwide distribution of tetraploid oyster germ plasm. It will also open new horizons in the breeding potential of tetraploids. Phase I is designed simply as a "proof of concept" for cryopreservation of tetraploid sperm. Our goal is to demonstrate that tetraploid sperm can be frozen, stored, shipped and thawed, and used to make healthy, 100% triploid crosses after as much as three months of storage. (Of course, overall we intend to store sperm for year-long intervals.) Our specific objectives are the following: (1) Optimize the cryopreservation of tetraplolid sperm and (2) demonstrate stable storage of the product by bioassays of thawed sperm in the hatchery. ANTICIPATED RESULTS & POTENTIAL COMMERCIAL APPLICATIONS OF RESEARCH Cyropreserved gametes (sperm in particular) will facilitate commercial production. A year's supply of tetraploid sperm can be frozen and stored and when needed, simply shipped in from a central storage facility. This would also alleviate the need to condition animals during periods of time when they are not normally sexually mature. Instead, tetraploids could ripen in the field, and batch processed once at the appropriate time of year. Cryopreservation also will allow distribution of tetraploid technology worldwide for creation of 100% triploid larvae and adults. Cryopreserved gametes will facilitate future research on breeding approaches using tetraploids of other species.
