| In the study, heritability, genetic correlation and path analysis were conducted for morphological traits. Heterosis and combining ability were analyzed with parents from wild populations (stocks). Inbreeding depression on early performance was calculated involving full-sib and half-sib mating. Family comparison and genotype-environment interaction were studied. The main results of the study were the following: 1 Heritability, genetic correlation and path analysis Twelve half-sib families and thirty-six full-sib families were obtained by a nested design of each male mated with three females. The heritability and genetic correlation were analyzed based on data of shell length and width. The results showed that at Days 6, 10 and 20, the heritability for shell length were separately 0.4891,0.4375 and 0.2022, the heritability for shell width being separately 0.4275, 0.3437 and 0.1423, the genetic correlation being 0.8605, 0.8494 and 0.7629. Shell length (X1), shell width (X2), shell height (X3), shell weight (X4), muscle weight (X5) and total weight (Y) were measured. The Pearson correlation coefficients among the traits were calculated. The total weight was used as dependent variable and the other traits were used independent variable for path analysis. The results showed that the correlation coefficients among the traits were significant (P<0.05). The correlation coefficient between shell length and total weight was highest, but shell length had a slightly direct effect and a highly indirect effect through shell width and muscle weight on total weight. The regression equation to estimate total weight was Y= -38.7123 + 0.5976 X1 +0.6156 X3 + 0.7753 X4+ 0.9981 X5 2 Heterosis and combining ability Four groups (AA, AB, BA and BB) were obtained by a full diallel design with parents from two wild populations. The heterosis for metamorphosis rate and growth of AB and BA were compared. The results showed: 1) Fertilization rate, hatching rate and metamorphosis rate of the four groups were significant (P<0.05). Growth was significant different among the four groups at Days 8, 20, 30, 43, 160, 300 and 330. 2) The heterosis for metamorphosis rate of AB and BA were 9.33% and 7.22%, respectively. 3) At ages, the heterosis for growth of AB ranged from -2.29% and 10.48%, the heterosis for growth of BA ranging between -6.83% and 3.36%. Two groups (BCA and BB) were obtained with females from the first generation of hybrid seed and males from Changhai in China. The heterosis for fertilization rate, hatching rate, metamorphosis rate and growth were studied. The results showed: 1) The fertilization rate of the two groups were insignificant (P>0.05), but the hatching rate and metamorphosis rate of the two groups were significant (P<0.05).2) At Day 8 the difference on shell length of the two groups was insignificant, however at Days 20, 30, 43, 160, 300 and 330 the difference on shell length was significant (P<0.05). 3)The heterosis for fertilization rate, hatching rate and metamorphosis rate were3.96%,20.09% and 13.61%, respectively. 4) At ages, the heterosis for growth was between 0.30% and 10.24%. Nine groups were constructed by a full diallel design with parents from three wild populations. Combining ability and heterosis were studied. The results showed: 1) At Days 8, 20, 40 and 94, general combining ability (GCA) was significant. At Days 20, 40 and 94, specific combining ability (SCA) and reciprocal effects (RE) were significant (P<0.05). 2) With ages, variance component percent for GCA decreased, while variance component percent for SCA and heterosis for growth increased. 3) At ages, correlation coefficient between GCA and heterosis was insignificant (P>0.05), while that between SCA and heterosis was significant. Total combining ability was significantly related to shell length of hybrid groups. 4 Inbreeding depressions Effects of inbreeding and maternity on early performance were studied in the Pacific abalone using two sets of 2 x 2 factorial crosses involving sister-brother mating. Metamorphosis success and larval growth in f...
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