马氏珠母贝杂交家系生长性状与遗传参数分析

【目的】探究不同杂交策略下马氏珠母贝二元杂交子代的生长性状和养殖存活情况，为广西马氏珠母贝群体杂交育种配套系构建及选择育种提供参考依据。【方法】以马氏珠母贝海选1号（H）自育F₄代群体和北海野生群体（Y）自繁F₁代群体为亲本，通过二元杂交构建36个正反杂交家系，并以H亲本和Y亲本的自繁群体F₁代分别构建对照群组（PH和PY）；各群组经海区养殖14个月后采集壳长（SL）、壳高（SH）、壳宽（SW）和体质量（BW）等数据，利用混合线性模型（动物模型）进行生长性状遗传参数估计。【结果】在H（♂）×Y（♀）杂交子代中，SL、SH、SW和BW的遗传力（h2）分别为0.241、0.149、0.220和0.062，遗传相关系数（γ_g）范围为0.894~0.964，表型相关系数（γ_p）范围为0.558~0.865；在Y（♂）×H（♀）杂交子代中，SL、SH、SW和BW的h2分别为0.110、0.156、0.121和0.067，γ_g范围为0.981~0.989，γ_p范围0.603~0.881；2个杂交子代的生长性状表现为中低遗传力，且遗传相关高于表型相关。Y（♀）和Y（♂）群体的一般配合力（GCA）较高，说明更适合用于杂交配套；H（♂）×Y（♀）杂交子代中SL、SH和SW的特殊配合力（SCA）相对较高，且均为中低遗传力。在2个杂交子代中，4个生长性状的杂种优势分别为-0.02%~2.82%和-0.03%~0.27%，均以SL的杂种优势最高、SW的杂种优势最低。在H（♂）×Y（♀）杂交子代中SL、SH和BW等3个生长性状的杂种优势家系率为50.00%~72.22%，优势家系选择率≥50.00%；养殖存活性状的超亲优势家系率为19.44%，杂种优势家系率为61.11%，2个杂交子代和PY群体均表现出优势存活性状。【结论】H（♂）×Y（♀）杂交子代具有生长性状优势，Y（♂）×H（♀）杂交子代具有存活性状优势，2个杂交子代均存在综合杂种优势，可进行一般杂交育种应用；北海野生群体亲本的GCA较高，其SL和SH的遗传力及与BW的遗传相关也相对较高，在进行广西马氏珠母贝群体杂交制种时可考虑以野生群体子代作为专门化亲本来源，且对2龄亲本性状选择上宜优先考虑SL和SH。

Growth traits and genetic parameters of hybrid families in Pinctada martensii

【Objective】To explore the growth and survival of two-way crossing hybrid of Pinctada martensii under different crossbreeding strategies，and to offer reference for the construction of cross breeding mating lines and selective breeding of P. martensii in Guangxi.【Method】36 hybrid families were esta blished in a complete diallel hybridization design which parents came from a F₄ generation Haixuan No.1 stock（H）and a F₁ local wild stock（Y）from Beihai. Control groups（PH and PY）were constructed from the F₁ generation of the H and Y parents. After 14 month’s mariculture， growth characters were compared among hybrid families（HY，YH）and purebred populations（PH，PY），genetic parameters of growth traits such as shell length（SL），shell height （SH），shell width（SW），and body weight（BW）were estimated by a mixed linear model（animal model）.【Result】Heritabilities（h2）of SL，SH，SW and BW of HY group were 0.241，0.149，0.220 and 0.062，respectively，while the range of genetic correlation（γ_g）and phenotypic correlation（γ_p） coefficient were 0.894-0.964 and 0.558-0.865. Heritabilities of SL，SH，SW and BW of YH group were 0.110，0.156， 0.121 and 0.067，respectively，while the range of genetic correlation and phenotypic correlation coefficient were 0.981- 0.989 and 0.603-0.881. The outcomes indicated that both two hybrid groups had medium-low heritabilities，and genetic correlation coefficients were higher than phenotypic correlation coefficients. The general combining ability（GCA）of Y （♀）and Y（♂）populations was high，indicating that Y（♀）and Y（♂）were more suitable for cross matching. The special combining ability（SCA）of SL，SH and SW of H（♂）×Y（♀）hybrids were high and had low-medium heritabilities. The growth heterosis（%）of four growth traits in the twohybrids ranged from -0.02% to 2.82% and -0.03% to 0.27%，respectively. SL had the highest heterosis，while SW had the lowest heterosis among all the groups. The proportion of families with heterosis in SL，SH and BW of H（♂）×Y（♀）hybrids ranged from 50.00% to 72.22%，and the selection rate of superior families was ≥50.00%. The proportion of over parent heterosis families in survival traits was 19.44%，while the proportion of heterosis families was 61.11%. Both the two hybrid groups and PY population showed advantageous survival rates. 【Conclusion】H（♂）×Y（♀）hybrids have advantage in growth，while Y（♂）×H（♀）hybrids have advantage in survival rate， and the two hybrid combinations all showcomprehensive heterosis，which can be used in general cross breeding. The offspring of Beihai wild population which with relative high GCA，heritabilities of SL and SH and high genetic correlation with BW，can be considered as specialized parental sources in the cross breeding of Guangxi P. martensii population. SL and SH should be given priority in the trait selection of 2-year-old parent individuals.