黄喉拟水龟（♀）与三线闭壳龟（♂）杂交后代的形态特征及其与父母本的比较研究

本研究通过黄喉拟水龟Mauremys mutica（♀）与三线闭壳龟Cuora trifasciata（♂）进行杂交，成功获得了杂种龟。这说明黄喉拟水龟和三线闭壳龟是可以进行属间远缘杂交的，但杂交组合的受精率及孵化成功率均低于黄喉拟水龟的同种组合。杂种稚龟与黄喉拟水龟稚龟在背甲纹路、腹甲黑斑、四肢和尾腹面的皮肤颜色、喉盾前端形状及起点位置、喉盾宽/喉盾缝长、喉盾缝长/肱盾缝长、股盾缝长/肛盾缝长存在差异。1龄前，杂种龟生长快于黄喉拟水龟。形态特征上，杂种龟头顶部淡棕黄色，头侧眼后有两条黑色纵纹，颈腹部淡黄色；背甲棕色，腹甲浅黄色，每一盾片中间都有边缘呈放射状的黑斑；四肢、尾腹面及裸露皮肤部分为黄褐色。形态可量数据分析显示杂种龟在形态上接近黄喉拟水龟。建立了三种龟的形态判别公式，判别的准确率为100%（p<0.01），判别分析中贡献最大的4个变量分别是腹甲后半部长/背甲长、喉盾宽/背甲长、肱盾缝长/背甲长、股盾缝长/背甲长，可见三线闭壳龟、黄喉拟水龟与杂交种腹部的腹甲后半部长、喉盾宽、肱盾缝长、股盾缝长等参数可作为鉴别三者的直接依据。本实验的结果对杂种龟的鉴定、龟类的杂交育种及养殖生产实践都有一定的借鉴作用。

THE MORPHOLOGIC CHARACTERS OF HYBRID (MAUREMYS MUTICA ♀× CUORA TRIFASCIATA ♂)AND COMPARISON WITH THEIR PARENTS

Yellow pond turtle, Mauremys mutica and three-striped box turtle, Cuora trifasciata, is classified to Bataguridae, Mauremys and Cuora, respectively, they distribute in Southern China. The two turtles have been artificially-propagated successfully and were cultivated in a small-scale. Mauremys iversoni is a new strain nominated by Pritchard in 1991, but in 2001, two research groups leading by Parham and Wink proved that Mauremys iversoni was not a species. With different methods, they found that Mauremys iversoni may be the hybrid of yellow pond turtle and three-striped box turtle. In this article, the hybrid of M. mutica (♀) × C. trifasciata (♂) was acquired successfully, which indicated the hybrid between genus of Mauremys and Cuora was feasible. But the rate of fecundation and hatching of M. mutica (♀) × C. trifasciata (♂) were lower than M. mutica (♀) × M. mutica (♂). The veins on carapace, the dark patch on plastron, the forepart form and origination of gular acute, the ratio between gular acute width and gular acute seam length, gular scute seam length and humeral acute seam length, femoral acute seam length and anal acute seam length, the skin color of inside of four limbs and tail abdomen of the young hybrid were different from the young M. mutica. The growth rate of the one year old hybrid was faster than M. mutica in the same culture condition. In morphology of hybrid, the color of calvarias was thin brown-yellow, and it has two black lines behind the eyes, the abdomen of neck was yellow ; the carapace was brown and its plastron was thin yellow, each acute of plastron has radiated dark patch, the akin color of inside of four limbs and tail abdomen of the hybrid were yellow-brown. The analysis of morphologie data within three kinds of turtles indicated that the hybrid was more closed to its mother, M. mutica. Morphologic diseriminant formula of three turtles were obtained, discriminant analysis indicated that there were significant different among three kinds turtles. The identification accuracy was 100% (p ＜ 0. 01). The ratio between second half plastron length, gular acute width, humeral acute seam length, femoral scute seam length, respectively, and carapace length were the highest contributing rate on diseriminant analysis, which could be the direct parameter in distinguishing yellow pond turtle, three-striped box turtle and their hybrid. The study would be benefit to identification of hybrid, turtle breeding and aquaculture.