两水系三角帆蚌亲本及杂交、自交组钩介幼虫形态性状比较

对采集于长江和淮河水系的三角帆蚌亲本及正反交、自交组的钩介幼虫形态性状进行了测量和比较。结果显示:两个水系的三角帆蚌亲本形态差异显著。太湖三角帆蚌亲本群体较洪泽湖群体的壳顶位置偏向贝壳前端,壳高与壳长、壳宽与壳长的比值均极显著低于洪泽湖群体(P<0.01)。综合分析表明太湖三角帆蚌的壳型为长扁型,而洪泽湖三角帆蚌为圆润型。反交组(H0T)成熟钩介幼虫指数为(0.066 7±0.005 9),极显著高于正交组(T0H)和两个自交组(P<0.01),其杂交优势率为2.54%。以太湖三角帆蚌为母本的幼虫壳长与壳高的比值为(0.828 4±0.029 4),极显著低于以洪泽湖群体为母本的比值(0.848 2±0.034 5),而同一母本不同父本之间的钩介幼虫无显著差异(P=0.286,P=0.106),该性状表现为明显的母性遗传,这与已有的贝类杂交研究结论相似。而各组幼虫的寄生成活率、稚贝生长情况有待进一步研究。

Comparsion of morphological characters of broodstocks and their glochidia in reciprocal hrybird of Hyriopsis cumingii from two drainage systems

Morphological charaters of broodstocks and their glochidia were compared in reciprocal hrybid of triangle mussel Hyriopsis cumingii from two drainage systems.The results indicated that the umbo position of broodstock from Taihu Lake was significantly closer to anterior of shell,and the ratios of shell width and shell height to corresponding shell length were also obviously lower than those from Hongzehu Lake(P<0.01).The external feature of triangle mussel from Taihu Lake and Hongzehu Lake was long-flat type,round-plump type respectively.Glochidia Index of cross group H0T was(0.066 7±0.005 9),significantly higher than three other groups(P<0.01),and had observed heterosis(2.54%).The ratio of shell length to shell height of glochidia in Group T0H and T0T was(0.828 4±0.029 4),obviously lower than Group H0H and H0T which had(0.848 2±0.034 5)on average.T-test showed there was no significant difference between those groups which had the same source of female parents(P=0.286,P=0.106).These results indicated that this character was maternal inheritance,which was in accord with previous studies on intraspecific hybridization of mussel.More analysis will be concentrated on glochidia survival and growth of juvenile mussel in reciprocal hybird of this species.