Study On Genetic Law And Indirect Selection For Important Economic Traits Of Inner Mongolian Cashmere Goats At Different Staple Types

Inner Mongolia Cashmere Goats(IMCGs)is an excellent local breed by through long-term natural selection and artificial selection.It was found that the staple length(natural length)of IMCGs varies greatly among individuals.This study come true indirect selection for other important economic traits.The genetic regulation of staple types and synergistic changes trends of important economic traits(cashmere yield,body weight,staple dimeter,staple length,fiber diameter and fiber length)and secondary traits(cashmere yield/body weight,staple dimeter/staple length,fiber diameter/fiber length)with were studied,which will be helpful to increase the accuracy of phenotypic selection,And eliminates the disadvantages of time-consuming,high cost and High labor intensity of collecting data in progress of genetic estimation.Data for this study comes from in breeding farm of Inner Mongolia White Cashmere Goats.Firstly,the phenotypic genetic diversity and the genetic regularity of staple length were studied by using the data of staple length from 1990 to 2014.Secondly,the effects of staple types on other important economic traits were determined by variance and regression analysis using the data of fleece traits,body weight and staple length,staple diameter,fiber length and fiber diameter from 2008 to 2011.Finally,multitrait animal models were used to estimate the genetic parameters of important economic traits andecondary traits at different staple types.The results are as follows:1.The Shannon-Wiener index was used to discover the genetic diversity of staple using the staple length records from 1990 to 2014.It was found that the index of the long staple length was the highest,which indicated that the individuals with long staple length had high phenotypic genetic diversity.The Heterosis of mid-parent and best-parent increased with the increase of staple length.The best-parent heterosis of long staple type was obviously positive which indicated that the long staple type is stable of best-parent heterosis.2.Genetic parameters of different staple types by were estimated multitrait repetitive animal models.It was found that the heritability of short,mediate and long staple type were 0.11,0.16 and 0.22,respectively.The heritability of long staple type was the highest,and the heredity was relatively stable,and it was easy to be fixed in the breeding process.It was further indicated that the genetic progress of long staple type was faster.Meanly,the selection for long staple type could accelerate the genetic progress of staple length.3.Taking the repeated records of cashmere yield,body weight,staple length,staple diameter,fiber length and fiber diameter of IMCGs from 2008 to 20 11 as the research object,the variance and regression analysis showed that staple types had significant effects on the important economic traits.The staple diameter and fiber diameter decreased with the increase of the staple length,while the body weight and fiber length increased with the increase of the staple length.But cashmere yield in mediate staple type was lowest.4.Estimation of genetic parameters of important economic traits under different staple types were performed by using multitrait repetitive animal models.It indicated that the heritability of each trait increased with the increase of staple length,and the heritability of each trait was the highest in the long staple type,which indicated that the selection for long staple type was helpful to accelerate the genetic progress of each important economic trait.5.Variance analysis showed that staple types had significant effects on secondary traits,staple type should be considered as a fixed effect in animal model for genetic evaluation.The heritability of the secondary traits also increased with the increase of staple length,which indicated that indirect selection for other important economic traits could be achieved through the selection of staple length.