The mating of male and female ducks of different breeds is called hybridization. The offspring obtained by crossing two or more breeds have certain characteristics and properties of the parental variety, which enriches and expands the genetic material basis and variability. Therefore, hybridization is important for improving existing breeds and breeding new varieties. method. Since the hybrid generation often shows the characteristics of strong birth vigor, high survival rate, rapid growth and development, production of fleshy eggs, high feed rewards, adaptability, and strong resistance to disease, crossbred hybrids are used to produce heterosis in production. As a commercial duck, descendants are economical and effective. According to the purpose of hybridization, they can be divided into breeding hybrids (graded hybrids, introduced hybrids and bred hybrids) and economical hybrids (simple economic hybrids, three-way hybrids and productive two-hybrids). 1. Progressive hybridization Progressive hybridization (improved hybridization, transformation hybridization, and absorption hybridization) refers to crossing a high-yielding, good breed duck with a low-product female duck, and the resultant hybrid female ducks are then crossed with high-yielding, high-quality male ducks. Generally, 3 to 4 generations can be continuously performed to rapidly and effectively transform low-product species. When the need to completely transform the performance of a population (varieties, strains) or to change the direction of production performance, commonly used progressive hybridization. During hybridization, care should be taken to: 1 Select the appropriate modified species based on the direction of improving production performance or changing production performance. 2 Strict genetic testing of introduced improved ducks. 3 The hybrid algebra should not be too much, so as to avoid excessive proportion of foreign blood lineage, resulting in decreased adaptability of the hybrids to the local area. 2. Introduction of Hybridization Introduction of hybridization is the introduction of no more than 1/4 of the extracorporeal blood within the local range of the original population in order to overcome some of the disadvantages while maintaining the original population characteristics. When the production performance of the original population basically meets the requirements, the local defects are not easily overcome under pure propagation. In this case, introduction hybridization should be adopted. In the introduction of hybridization should pay attention to: 1 for the specific disadvantages of the original population, the introduction of the hybridization test, to determine the introduction of species of ducks. 2 Strictly choose to import populations and breeders. 3. Breeding Crossbreeding refers to the use of two or more populations to cross-bred to one another, to be selected and fixed in the progeny of the hybrid, and to develop a variety that meets the needs. When the original species can not meet the needs, and no foreign species can completely replace it, bred hybridization is often used. When breeding hybrids, attention should be paid to: 1 Requirements Foreign varieties have good production performance and strong adaptability. 2 Cross-breeding parents should not be too much in order to prevent the genetic base from being too mixed, resulting in difficulties in fixation. 3 When the hybridization appears ideal, it should be fixed in time. 4. Simple and economical hybridization (two-line matching) Two populations were crossed and the F1 generation heterosis was used to produce commercial ducks. When carrying out economical hybridization, it should be noted that: 1 Combining power must be measured before large-scale hybridization. Combining ability refers to the degree of heterosis that crosses of different populations can obtain, and it is an index to measure heterosis. 2 There are two types of combining force: general combining ability and special combining ability. A combination of the best special combining ability should be selected. 5. Three-way crossbreeding (three-line matching) Three-way crossbreeding refers to the hybridization of two populations of hybrids with the third population, using a multi-faceted heterosis with three populations for commercial duck production. When using this method, it should be noted that in the three-way hybridization, the first hybridization should pay attention to reproductive traits, and the second hybridization should emphasize economic traits such as growth. 6. Production two-hybrid (four-line matching) Production two-hybrid means that the four populations are divided into two groups and they first cross each other. After the hybrids are produced, the second hybridization is performed between the hybrids. Modern breeders often use inbred lines (lines with an inbreeding coefficient of more than 37.5%), specialized lines (specially used for cross-breeding production lines) or synthetic lines (based on good lines, through multiple generations of positive and negative lines between lines. Cross-breeding, the new strain formed by the breeding and breeding of hybrids).
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