菲律宾蛤仔家系的建立及早期生长发育

Preliminary study of establishment of families and their early growth and development for manila clam(Ruditapes philippinarum)

采用不平衡巢式设计建立33个菲律宾蛤仔家系(11个父系半同胞家系和33个全同胞家系),并对各家系蛤仔的卵径、受精率、孵化率及生长、存活和变态的相关指标进行了分析。结果表明:各家系蛤仔的卵径、受精率无显著差异(P>0.05,n=90),但孵化率有明显差异(P<0.05,n=90)。在不同时期各家系蛤仔的生长情况不同。幼虫期间,9日龄C2生长最快比生长最慢的F2平均壳长大28.24%,且差异显著(P<0.05,n=90)。D3绝对生长最大比平均值高37.24%。稚贝期间,40日龄I1生长最快比生长最慢的B3平均壳长大78.29%,且差异显著(P<0.05,n=90)。I1绝对生长也最大比平均值高87.61%,其中400～500μm个体占30%,500μm以上个体占53.33%,家系内个体趋于大型化,而B1、B3家系内个体生长性状出现衰退现象,趋于小型化,300μm以下个体分别占整个家系的83.33%、90%。在相同时期各家系蛤仔的存活率不同。幼虫期间,9日龄I2存活率最高比平均存活率高94.14%,E3存活率最低比平均存活率低72.65%。稚贝期间,40日龄时各家系稚贝的存活率较高,都在85%以上。变态期间,同胞家系出现变态延迟及变态规格小型化现象。附着变态时间从第15天延迟至22天,变态平均规格为(193.18±12.15)μm,K1变态最小规格为(183.00±14.42)μm,以K为父本的3个家系变态规格普遍偏小,表现出父本效应。各家系变态率不同,存在明显差异,E3家系变态率最高为(94.33%±0.58%),B2家系变态率最低为(7.33%±2.08%)。综合33个同胞家系的各项指标,I1早期生长抗逆性状最优,可进一步作为优良品种选育的育种材料。

A total of 11 half-sib families and 33 full-sib families were generated by using the method of unbanlanced nest design, in Sept. 2007. Phenotypic traits of different families, such as egg sizes, fertilization rates, embryonic hatching rates, larval and juvenile growth, survival and metamorphosis were analyzed. The results showed that the differences in egg sizes and fertilization rates among the full-sib families were not significant, but those in embryonic hatching rates were significant（ P 〉0.05, n =90 ）. The growth of each family was not the same at different stages. The fastest growth family named C2 was significantly larger than the slowest growth family named Fz by 28.24 % in average shell length （P 〈 0.05, n = 90）at 9 days of larval stage. D3 whose absolute growth was the largest of all families was bigger than the average absolute growth by 37.24%. The fastest growth family I1 at 40 days of nursing stage was significantly larger than the slowest growth family B3 by 78.29% in average shell length（P 〈0.05,n =90）. Moreover, I1 was the largest of all families in absolute growth, and it was bigger than the average absolute growth by 87.61%, the distributions of shell length between 400 - 500 μm and above 500 μm accounted for 30% and 53.33% of total shell length among I1 , respectively. However, the growth trait depression families B1 and B3 involved in miniaturization, the distributions of shell length below 300 μm accounted for 83.33% and 90% of total shell length of B1 and B3, respectively. The survival of each family was different at the same stage. The highest suevival family 12 was significantly larger than the average survival by 94.14% ,and the lowest growth suevival family F2 was obviously smaller than the average survival by 72.65% at 9 days of larval stage. The survivals of all families at 40 days of nursing stage were higher than 85%. The study of full-sib families at metamorphosis stage presented some phenomena, such as metamorphism time delay and metamorphism individual miniaturization. The metamorphosis time was delayed from 15 to 22 days. The average metamorphic size was （ 193.18 ± 12.15 ） μm . The smallest metamorphic size family was K1 with （ 183.00 ± 14.42 ） μm of shell length, and the metamorphic sizes of three families which were generated through each female mated with the same male named K were generally smaller than other families, and this was mainly due to paternal effect. The metamorphosis rates were significantly different among the full-sib families. The highest metamorphic rate family was E3 with the rate of （94.33% ±0.58%）, and the lowest metamorphic rate family was B2 with the rate of （7.33% ± 2.08% ） . These results suggest that I1 is a family with the best early growth and development traits, and it could be used to produce high-quality seed which presents short culture cycle, and higher production in artificial selection breeding.