孙小异建鲤工作室
Jian carp Cyprinus carpio var. jian was artificially bred in 1988, examined and approved in 1990, and examined and approved once again by the National Aquatic Animal Good Stock Examination Commission in 1996 and proclaimed by the Ministry of Agriculture as one of the first batch good stock adaptable to be extended in China the same year. It was the first approved aquatic species created by Professors Zhang Jiansen and Sun Xiaoyi, using integrated genetic breeding technology, including orientated selection through six generations, inter-strain hybridization, and chromosome engineering (gynogenesis). Jian carp is a good stock of cultivated fish species with stable genetic traits and has been extended to 27 provinces, municipalities or autonomous region in China and gained great social and economic benefits (Zhang and Sun, 1996).
Jian carp is also one of excellent aquatic species extended in the 11th Five Year Plan of China (2006-2010). The Journal of “Chinese Aquatic Products” recently published the authors’ new article in September 2006 for the first time to disclose the breeding techniques. The techniques are briefly introduced here (See Figure 1).
Figure 1 Schematic Diagram of Integrated Breeding Techniques of Jian Carp Cyprinus carpio Var. jian
Where there are four lines (1-4), two gynogenesis lines (5 and 6) (G1, G2). P represents parent, F1-F6 indicate filial generations. Hebao red common carp Cyprinus carpio var. wuyuanensis was used as maternal parent and Yuanjiang common carp Cyprinus carpio yuanjiang as paternal parent. Hebao red common carp originated from Wuyuan Jiangxi Province China with features of cultured species, orange color, short type, tender meat and small size. Yuanjiang common carp originated from Yuanjiang Yunnan Province China with features of wild species, black color, long spindle type, large size, meat quality rather tough. There are great genetic differentiations between the two, complementary each other in traits, with affinity strong, heterosis advantages significant and heterosis rate higher. W1, W2, W3, W4 represent four female Hebao red common carp while Y1, Y2, Y3, Y4 male Yuanjiang common carp. They were primitive parents of Jian carp. Pure parents in pair built an independent family line.
F1 is the first generation of hybrid. Its genotype is identical with its parents and its phenotype as well, color black but yellowish, bodily form short between paternal and maternal parents, a little to maternal parent (body length/body height 2.00 ± 0.25), heterosis advantages significant.
From hybridization, reciprocal hybridization and backcross between Hebao red common carp and Yuanjiang common carp the filial generations are all black color, so black is dominant character and orange is recessive character. Color is qualitative character. Bodily forms from hybridization, reciprocal hybridization and backcross are differential between two parents with no obvious dominant and recessive characters, but a little tending to maternal parent hereditary.
From F1 self-crossing caused segregation of F2 characters. It is due to law of segregation and recombination. In F2 generation the characters would have a wide segregation. Except color segregation bodily form would have wide segregation too and they could be F1 type, paternal type, maternal type and not clear type or other type recombination. The above– mentioned other type were a few, which grew faster with large size, long spindle type, but different with Yuanjiang carp with body length/body height (2.63 – 2.88) and black color. This is a hereditary type individual superior to their parents, the target of selection. The correct discrimination of these phenotype fish is very important.
Selected targets of F2 were reared through intensive culture, grading screen and finally three groups were selected to mate and achieved F3. Black color, long type, fast growth and large- sized fish were selected from F3 and reared in special pond in sparse, quick grow-out, and through grading four groups were selected for inter-strain crossing. The methods were Line 1 with Line 2 whereas Line 3 with Line 4 performing reciprocal hybridization. Male from Line 1 with female from Line 2; female from Line 1 with male from Line 2 crossing, the crossing of Line 3 and Line 4 were the same as Line 1 and 2. F4 growth advantages were obviously improved through inter-strain crossing. And then five – six pairs were finally selected from F4 generation for reciprocal crossing between two groups and males of two groups crossed with females of two gynogenesis lines and the filial generations as a whole were called F5.
F6 is the well bred generation and defined jian carp with color bright, black, long spindle type (body length/body height 2.68±0.38). The fish with these two traits account for 95%. In order to shorten the period of breeding and to speed up purification and stability of new species gynogenesis techniques was used. The female fish were synchronously selected from line selection (F1) i.e. long spindle type, black color, a hereditary type individual superior to their parents. Normal eggs gained after induced breeding were fertilized by semen of any other species pretreated by ultraviolet light and then treated by low temperature (0 - 2°C) it would inhibit the exude of the second pole of egg and would gain diploid of gynogenesis (G1, G2). The fish were all female and looked maternal parent, but still somewhat red color, with low survival rate, bad maturity. A few normal ones could be used for second generation of gynogenesis. It totally looked as maternal parent, 100% long type and black color indicating gynogenesis technique could be used to build asexual pure line rapidly, readily bred with sex inbreeding fish.
In a nutshell jian carp integrated breeding techniques can be summarized as the following focal points:
1) Combination breeding including line selection, inter-strain hybridization, gynogenesis and mixed selection;
2) Four line assortment techniques; 3) Sex and asexual inbreeding combination techniques; 4) Pyramid assortment techniques; 5) Genotype selection and homogeneous breeding techniques; 6) Bodily form selection technique;
7) Pedigree breeding technique; 8) Methodology of economic genetics; 9) Analytical techniques of DNA print and allele variables (Zhang & Sun, 2006).
Ref:
Zhang Jiansen & Sun Xiaoyi, 1996. Common carp hybrid and Jian carp culture, a textbook of Central Broadcast/TV University and Freshwater Fisheries Research Center. [The textbook provides how to breed common carp hybrid and develop it to a new common carp variety.]
Zhang Jiansen & Sun Xiaoyi, 2006. Disclosure and Analysis of Integrated Breeding Techniques of jian carp Cyprinus carpio var. jian 《中国水产》”Chinese Aquatic Products” 2006 (9) p69-72
|
|
