熊本牡蛎(Crassostrea sikamea)多嵴和无嵴品系子二代生长性状的选择效应

为了进一步检查熊本牡蛎(Crassostrea sikamea)多嵴品系及无嵴品系的连续选择反应能力,以两个品系子一代上选组为材料,以壳高为指标,按照10%选择强度,开展了两个品系子二代混合上选研究,评估了两个品系子二代选择反应、现实遗传力,计算了两个品系的遗传改进量。结果表明:两个品系仍具有较高的现实遗传力,多嵴品系遗传参数均大于无嵴品系,表现出较好的遗传改良效果。多嵴和无嵴品系幼虫期的选择反应分别为0.47、0.34,稚贝期为0.65、0.40,养成期为0.82、0.56;幼虫期的现实遗传力分别为0.27、0.19,稚贝期为0.37、0.23,养成期为0.47、0.32;幼虫期的遗传改进量分别为4.83%、3.61%,稚贝期为7.55%、5.76%,养成期为9.95%、6.47%。经过一周年的养成,多嵴品系壳高显著大于无嵴品系,两个品系现实遗传力分别为0.50、0.35,遗传改进量分别为10.13%、6.61%。由此可见,多嵴品系具有较快的生长速度,遗传改良潜力较大。本研究为熊本牡蛎遗传改良和新品系培育奠定了坚实的基础。

SELECTIVE EFFECT OF THE SECOND GENERATION FOR FAST GROWTH IN TWO STRAINS OF THE KUMAMOTO OYSTER CRASSOSTREA SIKAMEA

To examine response to selection, realized heritability, and genetic gain for in shell height of the cultchless Kumamoto oyster Crassostrea sikamea taken from the second generation in southern China, the selective effect was evaluated using multi-ridge and non-ridge strains by selecting the largest 10% oyster from two parents for of selected groups, while the equal number of the parents were randomly chosen as the control groups before the removal of parents for truncation selection. Results showed that the genetic parameters of the multi-ridge strain was were larger than those of the non-ridge strain, while two strain still existed and both were in relatively high genetic level. For multi-ridge strain, the response to selection and realized heritability were 0.47, 0.27 for larvae, 0.65, 0.37 for spat, and 0.82, 0.47 for grow out adult stage, respectively. For non-ridge strain, response to selection and realized heritability, they were 0.34, 0.19 for larvae, 0.40, 0.23 for spat, and 0.56, 0.32 for adult grow out stage, respectively. Genetic gain of multi-ridge and non-ridge strains was 4.83%, 3.61% for larvae, 7.55%, 5.76% for spat, 9.95%, 6.47% for adult, respectively. At the end of 360 day, the realized heritability and current genetic gain was 0.50, 10.13% for multi-ridge strain 0.35, 6.61% for non-ridge strain, respectively. This study shows that the multi-ridge strain has a potential of rapid growth rate and genetic improvement potential, which also and providesd a solid base for new strain cultivation as a solid foundation.