Toward a selective breeding program for South Sea pearl oysters in Indonesia JENS KNAUER 1 , DEAN JERRY 2 , JOSEPH J.U. TAYLOR 1 AND BRAD EVANS 2 At a time when there is so much discussion with regard to the potential of genetic improvement, it comes as a surprise to know that only approximately five percent of the species used in aquaculture have undergone some form of selective breeding. Although well-documented breeding and ongoing imquality, size and shape, and to develop the molecular tools that will allow a large-scale improvement program to be feasible. . provement programs, such as those for Atlantic salmon, tilapia, Pacific oysters and marine shrimp have highlighted the huge gains Fig. 1. Three-month old silver- or gold-lip pearl oysters in productivity that can be (Pinctada maxima). Initially, we will endeavor to identify a population of P maxima with attributes most suited to local Indonesian culture conditions by conducting a strain comparison trial. Pinctada maxima is widely distributed throughout the Indonesian archipelago in several biogeographical zones, so it is highly probable that wild populations achieved through directed selection, pearl production is one of many aquaculture industries that has yet to embrace modern breeding technologies. In 2003, South Sea pearl production based on the silver- or goldlip pearl oyster, Pinctada maxima, accounted for 0.6 percent (7 t) of global pearl production but 32.9 percent (US$ l 50 million) of total value (Anonymous 2005). To our knowledge, the P maxima industry still largely relies on animals that are, genetically speaking, essentially the same as their relatives in the wild and thus there is a lot of potential to improve on South Sea Pearl production through selective breeding programs. In 2005 Atlas Pacific P/L through its Indonesian subsidiary PT Cendana Indopearls, a major producer of South Sea pearls, and the School of Marine Biology and Aquaculture at James Cook University joined forces to work toward establishing a selective breeding program for P maxima. We believe this is the first attempt to launch a fully integrated selective breeding program for pearl oysters. The first phase of the project will be aimed at gaining fundamental information on the genetic basis of commercially important pearl traits, including color, lustre, skin with characteristics already suited to commercial culture exist. For example, there are likely to be significant differences in growth rate and disease tolerances among disparate populations simply due to adaptation to local environmental conditions. When a superior population is identified it will be utilized as the foundation genetic base for the selective breeding program. The environment and its interplay with the genetics of an individual may have a major effect on the growth and survival of P maxima as well as the quality of pearls produced. As a consequence, a major component of the initial phase of the project will be to assess the importance of local environmental conditions on the expression of these traits - the genotype by environment (G x E) effects. This can be determined by culturing animals from various populations at different localities throughout Indonesia. If the relative performance of the P maxima populations differ among the culture sites, then G x E effects are important in realizing the genetic potential of a trait and, as a result, a future selection program will have to be sitespecific. WORLD AQUACULTURE 25
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