Bay scallop X Peruvian scallop hybrid three-line breeding system and method

A three-line breeding method using Bay scallop×Peruvian scallop hybrids, the method comprising:

• 1) selecting F1 male-sterile individuals from F1 Bay scallop×Peruvian scallop hybrid families and also Peruvian scallop individuals from the corresponding selfing Peruvian scallop family, comprising:
• 1a) producing, for step 1b, F1 hybrid families wherein each family is produced using eggs from a Bay scallop and sperm from a Peruvian scallop, meanwhile each Peruvian scallop that provides sperm is used to produce a corresponding selfing Peruvian scallop family for step 1c,
• 1b) selecting, for step 2a, male-sterile individuals from the F1 hybrid families produced in step 1a, wherein the individual is determined to be male-sterile if it only spawns eggs;
• and
• 1c) selecting, for step 2a, Peruvian scallop individuals from each corresponding selfing Peruvian scallop family produced in step 1a;
• 2) breeding a male-sterile line, comprising:
• 2a) Producing, for step 2b backcross families wherein each backcross family is produced using eggs from a selected male-sterile F1 hybrid individual produced in step 1b and sperm from the corresponding selected Peruvian scallop individual selected to step 1c, meanwhile each Peruvian scallop that provides sperm is used to produce a corresponding selfing Peruvian scallop family for step 2b and step 2d;
• 2b) selecting from the backcross families produced in step 2a, for step 2c, a backcross family wherein each individual in this family is male-sterile/female-fertile, wherein the individual is determined to be male-sterile/female-fertile if it spawns only eggs and the spawned eggs can be fertilized by sperm of the selected Peruvian scallop individuals from the corresponding selfing Peruvian scallop family produced in step 2a and produce progenies;
• 2c) obtaining male-sterile line, wherein the backcross family produced in step 2b is selected as the male-sterile line;
• and
• 2d) selecting, for step 3, the selfing Peruvian scallop family corresponding to the male-sterile line selected in step 2c;
• 3) obtaining a maintainer line from step 2d, wherein the selfing Peruvian scallop family selected in step 2d is selected as the maintainer line specific for the male-sterile line produced in step 2c, as this selling Peruvian scallop family is able to render the male-sterile/female-fertile characteristics to the progenies of the male-sterile line produced in step 2c,
• 4) breeding a restorer line, comprising:
• 4a) producing, for step 4b, hybrid families using eggs from individuals of the male-sterile line produced in step 2c and sperm of Peruvian scallops that are not genetically related to the male-sterile line produced in step 2c, meanwhile each Peruvian scallop that provides sperm is used to produce a corresponding selfing family for step 4c,
• 4b) selecting, from the hybrid families produced in step 4a, a hybrid family wherein each individual in this hybrid family is hermaphroditic;
• and
• 4c) selecting a restorer line, which is the selfing Peruvian scallop family produced in step 4a corresponding to the hybrid family selected in step 4b, as this selfing Peruvian scallop family is able to restore the male-fertility of the progenies of the male sterile line produced in step 2c;
• and
• 5) reproducing the three-line breeding system, wherein a next generation of male-sterile line is produced by fertilizing the eggs of the male-sterile line produced in step 2c with the sperm from the corresponding maintainer line produced in step 3, and the commercial hermaphroditic hybrid scallops are produced by fertilizing the eggs of the male-sterile line produced in step 2c with the sperm from the corresponding restorer line produced in step 4c.