3个地理种群三角帆蚌育珠相关性状比较及壳重的通径分析

对3个野生三角帆蚌种群的贝壳形态及珍珠层颜色特征进行比较分析。结果表明:洞庭湖(DT)种群贝壳为短圆型,太湖(TH)种群为长扁型,而鄱阳湖(PY)种群介于两者之间;洞庭湖种群的体重指数、壳重指数、壳宽指数及壳厚指数等育珠相关性状均显著高于其他两个种群。对壳重的通径分析表明:3个群体中,壳厚对壳重的直接影响最大,壳长次之,壳高、壳宽主要通过壳厚和壳长间接影响壳重。在珍珠层边缘区域,后端出现紫色的比例均高于前端(P=0.055)。3个种群珍珠层颜色存在显著的种群特征:鄱阳湖种群中70%个体珍珠层为紫色或淡紫色,而洞庭湖和太湖种群在边缘区前端以白色为主,后端以紫色和淡紫色为主,中央区以紫色和淡紫色为主;在太湖种群中出现特征性的淡蓝色(20%);鄱阳湖种群珍珠层中出现不规则形态的金黄色斑频率最高(100%),洞庭湖种群中出现频率为45%,而太湖种群最低(15%)。综合分析认为:洞庭湖种群育珠相关性状显著优于鄱阳湖和太湖种群,其体型有利于作育珠蚌受体选育,培养大颗粒优质珍珠;太湖种群体型为长扁型,作为小片蚌可以增加小片的数量,且培育淡蓝色珍珠具有一定潜力;鄱阳湖种群珍珠层紫色特征明显,有利于紫色小片蚌品系的人工选育。研究亮点:珍珠颜色是评价珍珠品质及价值的重要指标之一。本文对三角帆蚌3个地理种群的贝壳形态特征进行了系统的比较,并首次研究了贝壳珍珠层颜色的分布特征。不同种群三角帆蚌贝壳形态、珍珠层颜色分布存在明显种群特征,鄱阳湖种群珍珠层颜色以紫色为主,太湖种群出现特征性淡蓝色。本研究结果对开展三角帆蚌珍珠单色品系,如紫色珍珠、白色珍珠或淡蓝色珍珠品系的人工选育研究具有重要参考价值。

Comparison of morphological traits related to pearl performance in Hyriopsis cumingii from three geographical populations and path analysis on shell weight

Morphological traits related to pearl performance were compared in triangle pearl mussel Hyriopsis cumingii from three geographical populations.The external feature of triangle mussel from Dongting Lake (DT) and Taihu Lake (TH) is round plump type and long flat type respectively. DT population is significantly higher than other two populations in traits related to pearl performance, inculding body weight index, shell weight index, shell width index and shell thickness index. Path analysis indicates that shell thickness has the greatest direct effect on shell weight, and shell length is the sencondary direct factor, whereas shell height and shell width have greater indirect effect. The ratio of purple color in posterior margin area is higher than that in the anterior in all three geographical populations (P = 0.055). More than 70% individuals from Poyang Lake (PY) have purple or lavender nacre color in all areas, while most of individuals from DT and TH have white nacre in anterior margin area, and show purple or lavender in posterior margin and central nacre area. There are 20% individuals with light blue nacre observed only in TH population. The golden yellow mottling with irregular shape randomly appears in PY population with higher ratio (100%) than DT (45%) and TH population (15%). All results show that DT population shows more suitable morphological triats related to pearl performance which can be used as furture broodstock in recipient mussel seletive breeding, while TH population has potential for donor mussel and new strain with light blue narce selection, and PY population shows greater potential for new strain with purple nacre selection.