Effects Of Temperatures On Gender And Growth Development For The Doubled Haploiods In Paralichthys Olivaceus

Japanese flounder(Paralichthys olivaceus)is one of important commercial fishes for sea farming in China.As the growth rate of female is significantly faster than that of male.To improve the aquaculture yield and economic interest,all female population construction is extremely important by inducing mitotic gynogenesis.Homozygous progeny can be produced by inducing mitotic gynogenesis,namely doubled haploid(DH),which with highly homozygosity,were precious genetic research materials.In this study,the eggs were induced mitotic gynogenesis in 17?.At 10 day-post hatch,the larvae were transfereed into three pond with temperature of 20,24 and 28? respectively.The double haploid group were obtained after 100 days.Sex identification and ratio were analyzed by the histological sectioning.The growth traits(body weight,total length and body height)were measured and analyzed.Multiple growth traits were compared by the Joint static algometry model.Aimed at provide important judgment basis of temperature for sex determination and growth,and laid the theoretical foundation for genetic breeding research work.And improving morphological traits and body weight synchronously in DH of Japanese flounder.The results of the study are as follows:(1)The population under 20? was with a slight masculinization and the proportion of male and female was 46.6%and 53.4%.With the increase of the temperature,masculinization was significant arised and the male ratio under 24? and 28? were 60.3%and 98.3%respectively.Chi-square test showed that compared with the DH population under 20,24 and 28? have significant difference(P<0.01)in masculinization.(2)The Normal distribution show that the body weight,body height and body length of DH population under 24? were approximate to normal distribution,the 20 and 28?were not.The single factor variance analysis of growth traits(body weight,body height,body length)for three DH populations showed:Compared to 20? and 28?,the 24? has a significant impact on body weight,body height and body length in DH of Japanese flounder.(3)Body weight,head length,caudal peduncle height,caudal peduncle length,body height and full length of the male in DH of Japanese flounder under 24? were significantly different from the males of other two populations.The values of these growth traits under 24? are higher than other two temperature.Compared with the culture temperature 20 and 28?,the DH of Japanese flounder under 24? growed faster.(4)Using the Joint allometry scaling model,comparing the allometric differences of three DH populations The result shows:the body height,body length and full length all have higher allometric relationships to body weight which indicated that the growth rates of body height.Body length and full length are faster than body weight.Among them,the allometric growth indexes maximum value of the body height and full length appeared in 24oC group,while the allometric growth index maximum value of body length was in 20?group.At the same time,the allometric growth indexes of body height and full length of the females in 20? group were higher than males,and the allometric growth indexes of body height and body length of the females in 24? group were higher than in males.