【摘要】 <正> 自六十年代以来,不少鱼类遗传育种学家企图应用人工雌核发育的手段为快速建立鱼类纯系摸索一条新的途径。但是,由于人工雌核发育的成活率极低,且可能全为雌性,因而致使有些学者怀疑这一途径的实践意义。Baldwin等早已提出在性分化前应用性激素可能引起鱼类性转化。以后在鳉鱼上的实验获得了成功。近年来,在罗更多还原

【Abstract】 This investigation was carried out in order to develop a new way of establishing a pure line through combinating the artificial gynogenesis with the artificial functional sex reversal in carp (Cyprinus carpio).The sperms irradiated by 60Co gamma rays (150 thousands of roentgen) or the ui-traviolent rays (30Wx2,in a distance of 17 cm,with a duration of an hour) prior to fertilization have the ability of activiting carp eggs.The embryos activated by the sperms irradiated by gamma rays are all gynogenetic and without any hybridizating embryos.It is inconvenient to use gamma rays as a radiating agent for an expensive safe protective equipment is required.On the other hand,the application of ultravio-lent rays as radiating agent can be easily accepted by the general research and production units as it is cheap and only simple safe equipment is needed,but the ultraviolent rays can not effect the sperms completely.Hence it is most important to choose those sperms when some of them are not affected by the ultraviolent radiation for any fusion with the proneucleas of the egg will produce hybrid embryos with features differing from gynogenetic embryos.There is no substantial difference between the frequencies of the fertilization with a normal sperms and the activiation by the irradiated sperms.The majority of the gynogenetic embryos show a typical haploid syndrome and die at the hatching stage.The frequency of the gynogenetic diploid is very low (1.35-1.5%),but it could be increased by applying artificial diploidization methods.When the gynogenetic eggs are cold shocked at about 0C for 30 min,3-5 min after fertilization the frequency of the diploid embryos could be increased to 17.4%,and even to 31.6% when the gynogenetic embryos in the 2 cell stage are immersed in the 25 or 100 ppm colchicine solution for 30 min.Using the diet with 30 ug/g methyltestosterone in it for fries from hatching up to 90 days or for fingerlings from 30 days after hatching up to 120 days,100% functional sex reversal is obtained.While using the diet with 500ug/g testosterone propiona-te in it for young fish from 5 months on with a duration of 40 days,the sex-differentiated immature females also show masculinization.The administered fish are developed into gynadromorphism,with spermcytes,mature spermatozoa as well as oocytes (stage III) in the gonads.Thus far we have developed a new complete breeding process of combinating artificial gynogenesis with artificial sex reversal.Bach individual fish of a second gynogenetic generation will be homozygous at many loci,so the inbreeding of her sex reversible "sons" and "daughters" will produce a pure line.更多还原