33results about How to "Avoid inbreeding depression" patented technology

The invention relates to a breed conservation, screening and breed production method in tilapia complete set lines, comprising the following steps of: construction of complete set line base populations rich in hereditary variation, establishment of operation procedures of family production and management in the complete set lines, marking of individuals in the complete set lines, genetic evaluation analysis of important production traits and establishment of individual mating selection programs in the complete set lines. The invention also provides a hybrid breed production method between twolines of complete sets, which is established by utilizing the method. The method disclosed by the invention has the characteristics of high pertinence, high selection breeding efficiency, capability of effectively preventing parent inbreeding depression of the complete set lines and the like; the harvest weight of the hybrid fine breed of tilapia is averagely increased by more than 30% than that of control groups; and the culture survival rate is also obviously higher than that of the control groups. According to the invention, a new technical approach is developed for cultivation of fish fine breeds; particularly a new selection breeding method is applied in the breed conservation, the screening and the breed production of the complete set lines in fish hybrid breeding; and the method isalso suitable for being popularized and applied in all cultured fishes and has broad popularization and application prospects.

The invention discloses multi-character selection breeding method of fish and shrimps. The method comprises the following steps of: firstly obtaining individual selection indexes and family selection indexes according to measured values of breeding target characters, then reserving stocks and hybridizing according to the selection indexes, building family mating groups and finally obtaining bred populations of the next generation. Moreover, when the individual selection indexes are obtained, the stock reservation rate and the heritability of breeding target characters are firstly calculated according to the measured values of the breeding target characters, expected selection intensity is calculated according to the stock reservation rate, then an expected selection response and a corresponding weighted value of each breeding target character are obtained according to the expected selection intensity, the heritability and the standard difference of a standardized breeding value, and finally the individual selection indexes are obtained by using the weighted value. Therefore, the subjectivity and the randomness during calculation of the weighted value are eliminated, the reliability and the accuracy of the breeding method are high, and the comprehensive genetic progress of multi-character selection is improved.

The invention discloses an aquatic animal selective breeding method adopting a group as a unit, and the method comprises the following steps of establishing a basic group adopting the group as a unit to form a current generation group; acquiring a group selective index; sorting a seed group and a seed individual; selecting pairing groups, establishing a mating group, and generating a next generation group; setting a virtual male parent and a virtual female parent for each next generation group; and repeating the steps to acquire the needed next generation group. By utilizing the selective breeding method, the technical difficulty that the breeding target trait test, genealogy establishment and orientation mating of aquatic animals of the individuals or family marks cannot be implemented can be effectively solved, the genetic evaluation of multiple breeding target traits and multiple generations can be realized, and the selection progress and the selection accuracy of the breeding target traits can be improved.

The invention provides a multi-family hybridization seed production method of prawn, belonging to the field of genetic breeding of aquatic products. The method specifically comprises the following steps of: through setting and calculating a selection index, selecting high-quality families and individuals to construct a propagation starting group; setting an upper limit of relationship coefficient, designing a plurality of mating groups by taking the families as units, establishing a single-level propagation unit and constructing a single-level propagation group; designing the mating groups according to the production capacity and market demand of offspring seeds by virtue of a previous-level propagation unit under the condition of a limited relationship coefficient, establishing a new level of propagation unit and constructing a multi-level propagation group; carrying out grouped or hybrid seed production by using the propagation unit in the single-level propagation unit or the multi-level propagation group so as to produce and supply commercial offspring seeds for prawn farmers. Based on the characteristic that female prawn has a high egg laying amount, a single-level or multi-level propagation method is designed, selection with a certain intensity is performed on each level of propagation group so as to quickly transfer and magnify the obtained genetic increment, the propagation mode is flexible in design and can meet different demands on offspring seeds.

The invention discloses a quantitative character gene pyramiding breeding method for pinctada fucata. The method comprises the following steps of: collecting at least three pinctada fucata groups from different sources, constructing F1 generation diallel crossing families, evaluating every each family after cultivating for one year, computing an average breeding value, and selecting families of which the breeding values are ranked at first 50 percent for serving as candidate families for constructing a core breeding family, wherein every each combination comprises at least ten families; screening female and male individuals from the candidate families, selecting female and male individuals which are ranked at first 100 places in sizes for measuring, computing individual breeding values, and sequencing; selecting female and male individuals with highest individual breeding values from families with highest female and male breeding values for mating respectively, selecting female and male individuals of which the individual breeding values are ranked at first places from families of which the female and male breeding values are ranked at second places for mating, and so on, and constructing an F2 generation core breeding family; and constructing multiple generations of families including F3, F4, F5 and the like according to the method for breeding generation after generation to over five generations. Through breeding according to the method, the genetic improvement of every each generation can be over 10 percent, the inbreeding coefficient can be controlled at a set level, and inbreeding depression is avoided.

The invention discloses a specific molecular marker primer for genders of trachinotus ovatus. The specific molecular marker primer is a primer P1 including a forward primer P1-F and a backward primerP1-R, and base sequences of the forward primer P1-F and a backward primer P1-R are respectively represented by SEQ ID NO:1 and SEQ ID NO:2. The invention further discloses a kit for identifying the genders of the trachinotus ovatus and application of the primer or the kit in identification of the genders of the trachinotus ovatus. The specific molecular marker primer is good in specificity and high in sensitivity and accuracy, is harmless to living trachinotus ovatus, can be used for rapidly and accurately identifying the genders of the trachinotus ovatus in batch at a time and has important scientific research values and practical application values.

The invention discloses a method for raising a novel strain of meat sheep. The method includes carrying out crossing on Hu sheep and Australian white sheep to obtain a first crossed generation of flock of sheep; carrying out crossing on high-quality ewes of the first crossed generation of flock of Australian-Hu sheep and Charolais sheep to obtain a second crossed generation of flock of sheep; carrying out athwart crossing and fixation on the second crossed generation of flock of sheep; appropriately introducing 'new blood' into the second crossed generation of flock of sheep to prevent inbreeding depression; ultimately raising the novel strain of meat sheep by means of strict feeding and management and ideal typical individual selection. The Hu sheep is used as a female parent, and the Australian white sheep is used as a male parent. The high-quality ewes of the first crossed generation of flock of Australian-Hu sheep are used as female parents, and the Charolais sheep is used as a male parent. The invention further discloses matched fattening fodder for raising the novel strain of meat sheep. The method and the matched fattening fodder have the advantages that diarrhea of lambs in weaning periods can be reduced by the aid of the fodder, body physiological functions of the sheep, the growth rates of the sheep in later periods and fodder digestion and utilization can be improved, the method and the matched fattening fodder are matched with modern genetic breeding and reproducing techniques, and accordingly the novel strain raising success rate can be effectively increased; the meat performance of the novel strain of the meat sheep raised by the aid of the method and the matched fattening fodder can be improved on the basis that the high reproductive capacity of a variety of the Hu sheep is maintained.

The invention relates to the technical field of preparation of good offspring seeds of economic marine shellfish, in particular to a backcross seed production method for hybrid scallops of argopecten purpuratus and argopecten purpuratus. A large number of unfertilized eggs or eggs with low fertilization rate of hybrid scallops of argopecten purpuratus and argopecten purpuratus are utilized to perform interspecific backcross with high-concentration semen of argopecten purpuratus, so that the seed production efficiency and yield of backcross first-generation scallops are improved, and high-quality backcross first-generation scallop seedlings which are fast in growth, large in size, high in corm yield and strong in stress resistance are obtained. According to the method, the proportion of hermaphrodite argopecten purpuratus and argopecten purpuratus hybrid scallop backcross offspring and argopecten purpuratus backcross offspring can be remarkably increased, so that backcross scallop offspring seeds with remarkable growth advantages, high survival rate, high stress resistance and high yield are prepared on a large scale; in addition, the method can be used for preparing hermaphrodite scallop interspecific hybridization commodity fries with extremely remarkable heterosis on a large scale.