Genotype By Environment Interactions And Estimation Of Nacre Color Of The Pearl Oyster Pinctada Fucata

Pearl oyster, Pinctada fucata, is the main pearl oyster to produce the pearl in theworld, it mainly distributes in tropical and subtropical areas. Three selected familiesof P. fucata were obtained to compare the growth of four traits and genetype andenvironment interactions at different stages in three different environments whichlocate in Hainan, Guangdong and Guangxi. The effect of interaction to growth can beused to select and extend breeding populations which can be best cultured in specificenvironmrnts. The pearl’s color is one of the most important factor to value thequality of pearl. The pearl’s color is influnced by shell nacre color of donor pearloyster. The experiment used16full-sib families and9populations from completedialled crosses from three base population of P. Fucata to analyze Lab and tristimulus,and compare shell nacre’s chromatic abrration Eabof each groups and select properfamilies and populations to be donor pearl oysters. Estimate the hebitarity of colorparameters was order to provide theoretic basis for select high quality donor pealoyster P. fucata to support pieces of mantle.1. Research on genetype×environment interactions in the pearl oyster PinctadafucataIn this experiment, we select three typical families of fast, average and slowgrowth (namely family1,2and3) and culture in Li’an, Lingshui (Hainan), Tandou,Zhanjiang (Guangdong) and Bailong, Fangcheng (Guangxi) for one year. Eighthundred individuals per family are cultured in each place. The three families wereconstructed in Janunary2012. The multiple ANOVA and the effect of the additivemain effects and multiplicative interactions (AMMI) were used to analyse the effectsof G×E interaction at different growth stages. Results showed that the growth rate ofdifferent growth traits of P. fucata in different sites is significantly different(P<0.05).The fastest growth rate appeared in Li’an， Hainan, which the slowest rateappeared in Bailong, Guangxi. F1has the fastest growth rate in total weight, which F3had the slowest rate. F2had the fastest growth rate of shell length, shell height andshell width.Totally, the proportion of genotypic, environmental and G×E interaction variances were72.47%-88.55%,9%-24.13%and3.32%-4.04%for the four traits,respectively. In different growth stages, genotypic variance reduced from92.32%-98.66%to32.45%-68.10%. Instead, environmental variance increased from0.11%-1.27%to24.41%-62.26%. G×E variance increased from0.79-3.9%to3.84%-7.51%. Analysis of AMMI1biplots of four traits showed that Family1hadinteractions with Tandou, Family2had interactions with Li’an. Family3is the moststable family..Above of all, the effect of G×E interaction was small. Family had agreat contribution to phenotypic variation. Our observations will provide an academicsupport for selective breeding and extension of the animal.2. Study on Growth Model of selected families of pearl oyster(Pinctada fucata) inthree environmentsIn order to test the fitting effect of different growth models on the growth ofthree selected families cultured in three different environments, four non-lineargrowth models von Bertalaffy, Gompertz, Logistic and Brody were adopted to fit fourgrowth traits(three morphological and one development traits) of families in threeenvironments(Lian Hainan, Tandou Guangdong, Bailong Guangxi) respectively. Weobtained the growth and development parameters using Levenberg-Marquardtiteration method. We got the best fitting growth model according to the optional valueof each growth parameters and the effect of genetype and environment interaction.Theresults showed that: The fitting growth model of shell length, shell height, shell widthin three sea sites is Brody model. The fitting growth models of weight are vonBertalanffy model in Lian and Tandou and Brody model in Bailong. Growth modelsreveal the growth pattern of the different families in different sea sites and provide atheoretical basis of promotion and selective breeding of P. fucata.3. Analysis of shell nacre color in16full-sib families of pearl oyster (Pinctadafucata)16full-sib families were obtained. Analyzed average value for Lab andtristimulus and compared chromatic abrration Eabamong16full-sib families of P.fucata showed that the values of L(light), a(red ang green) and b(yellow and blue)were98.586-105.234,-6.577--0.967and5.915-11.237respectively. The color of F14was close to green(-a), while F16was close to yellow(b). The biggest Eabis7.885,which presented between F3and F14that we could observe it easily. The colors of allfamilies were belong to white. Among them, We got F1as the best fitting donor pearloyster P. fucata to provide pieces of mantle because the small color differences of individuls and the shortest distant to white center.4. Estimates of heritabity for shell nacre color in a complete diallel cross of threepopulations of pearl oyster (Pinctada fucata)Nine populations of the first generation of complete diallel crosses from threebase populations(Sanya, SY, Shenzhen, SZ and Yuenan, YN) of P. fucata SY×SY(P1)、SZ×SY(P2)、YN×SY(P3)、SY×SZ(P4)、SZ×SZ(P5)、YN×SZ(P6)、SY×YN(P7)、SZ×YN(P8)、YN×YN(P9) were obtained. Analysis of chromaticabrration Eab among nine populations of P. fucata showed Eabbetween each twopolulation’s shell narce was above1.5, except1.353between P2and P7, which meansshell narce color among polulations of P. fucata has obvious differences. The biggestEabis5.339, which presented between P3and P5. According coordinates on CIE colordiagram and the values of parameters, we knew that the color differences of individulsfrom P5is small and the colors are near silvery white. So we got P5as the best fittingdonor pearl oyster P. fucata population to provide pieces of mantle. We estimated thenarrow-sense heritability of parameter L a, b were0,0.0866and0respectively. Andthe broad-sense heritabity of parameter L, a, b were0.1199,0.0352and0.0575respectively. The result showed that addictive genetic effect heterosis genetic effectcould not have a good influence on determining shell narce’s color heritabity of pearloyster P. fucata. We preliminary forecasted that it is difficult to select fitting donorpearl oyster P. fucata which have pretty shell narce’s color.