Present situation and Prospect of Research and Development of New Aquatic products in China

Improved varieties of aquatic products generally refer to the original species and new varieties of aquatic products with excellent economic characters and production performance. At present, although the research and development of new aquatic products in China is stimulated by some favorable factors, such as policy support, technical guarantee, social demand and so on, however, it is still faced with the decline of germplasm resources, the dependence of important provenances on imports, the immature research and development system, the lack of promotion ability and other factors, and there is a long way to go in the future.

Basic situation of research and development of new aquatic products

Course of development

Although the development of aquaculture in China has a long history, which can be traced back to the Shang and Zhou dynasties, about 3000 years ago, the research and development of varieties began in the 1960s, and at first only carried out conscious artificial improvement of some farmed varieties. The development process is roughly divided into three stages: the first stage, before 1957, the stage of extensive production of seedlings. The supply of seedlings mainly depends on the collection and cultivation of natural waters, and the collection and catch of seedlings reached 23.4 billion in 1957. The second stage is to break through the stage of artificial reproduction. After China broke through the artificial reproduction of domestic fish in 1958, the artificial breeding techniques of a large number of wild and domesticated species were broken through. At the same time, the introduction and trial breeding from abroad has also formed a certain industrial scale. The third stage, the initial stage of cultivation and research and development. With the rapid development of aquaculture, the frequent occurrence of aquaculture diseases caused by the degradation of aquaculture varieties in the late 1980s and early 1990s, there is an urgent need to develop new aquaculture varieties. 1991 the state has established a national committee for the examination and approval of original and improved varieties of aquatic products, and the examination and approval of new varieties of aquatic products has also been officially put on the agenda. In the 1990s, Xingguo red carp, purse red carp, Pengze crucian carp and other new aquatic varieties were bred. Since then, the research and development of new aquatic products in China has begun.

Breeding research and development technology

At present, the research and development technology of aquatic breeding in China mainly includes selective breeding technology, cross breeding technology, cell engineering breeding technology and molecular breeding technology. The technology of group selection is the most studied and widely used. Since 2000, multi-character compound technology has been introduced and established in China, which has been rapidly popularized and applied in many farmed varieties. This technique establishes families on a large scale, identifies families and individual markers, and uses pedigree and measurement information such as individuals, siblings, ancestors and offspring, through constrained maximum likelihood (restrictedmaxi? Mumlikelihood,REML) and the best linear unbiased prediction method (bestlinearunbiasedprediction,BLUP) were used for genetic evaluation, and the retained parents were selected according to the comprehensive selection index to strictly select and mate at the family and individual level, so as to solve the problem of inbreeding and germplasm degradation.

Cross breeding is to make full use of the complementary effects among populations, especially the heterosis. The so-called heterosis refers to the hybrids produced by the hybridization of different populations, whose vitality, growth potential and production performance are better than the average values of the two parent populations to some extent. In aquaculture, there are two ways of cross breeding: intraspecific hybridization and interspecific hybridization. The main target characters of intraspecific hybridization are growth rate and stress resistance, and the goal is to cultivate new varieties with high yield and strong stress resistance. Interspecific hybridization can be used to improve growth rate, adjust sex ratio, cultivate sterile population, improve meat quality, enhance disease resistance, enhance adaptability to extreme environment, improve important economic traits and so on.

Cell engineering breeding technology and molecular breeding technology are relatively novel technologies. Cell engineering breeding technology is a breeding technology to improve varieties by genetic operation at the cell and chromosome level, and it is one of the research hotspots in recent years. At present, the research on cell engineering breeding technology of aquatic organisms mainly includes polyploid breeding, gynogenesis, unisexual seedling cultivation, cell fusion and nuclear cytoplasmic hybridization (nuclear transfer) and so on. In the aspect of molecular biology technology, molecular assisted breeding technology and whole genome breeding technology have been explored and studied, and the related technical system has been preliminarily established. at present, the study of biological molecular markers in aquaculture is mostly through the screening of various molecular markers associated with target traits, so as to achieve the purpose of indirect assisted breeding.

Research and development achievements

According to statistics, at present, thousands of species of aquatic organisms have been reported in China, of which there are more than 170 species that can be cultured, and more than 40 kinds of main economic species. Mainly include "four big fish", common carp, crucian carp, bream, mandarin, tilapia, eel, sea bream, snakehead, perch, catfish, yellow catfish, flounder, grouper, channel catfish, yellow croaker, salmon trout, turbot, Sturgeon, crayfish, shrimp, crayfish, scallops, oysters, clams, pearl shellfish, abalone, kelp, seaweed, undaria, sea cucumbers, sea urchins, turtles, etc. These are the main objects of the research and development of new aquatic products in China at present.

As of 2015, 156 new aquatic varieties have been announced by the Ministry of Agriculture. In addition to 30 introduced species, 126 new aquatic varieties have been independently cultivated, of which 76 are selected for breeding, accounting for 49%; 45 hybrids, accounting for 29%; and 5 other categories, accounting for 3%. In addition to grass carp, important farmed species have basically achieved breakthroughs in new species. There are 87 fish (56%), 14 shrimp (9%), 5 crabs (3%), 21 shellfish (13.5%), 21 algae (13.5%) and 8 other species (5%). It mainly shows the following characteristics:

First, the annual average number of breeding is gradually increasing. A total of 40 were completed before 2000, 21 from 2001 to 2005, 39 from 2006 to 2010 and 56 from 2011 to 2014 (see figure 1 for details). The number of shellfish and algae has increased significantly in recent years. Of the 42 new varieties of shellfish and algae, 25 were completed in the past 4 years.

Second, some varieties have obvious advantages. Carp, crucian carp, tilapia and kelp new varieties more. There were 4 registered introduced species of carp and 24 self-cultivated species; 12 non-registered introduced species of crucian carp and 8 self-cultivated species of tilapia; 10 non-registered introduced species of kelp. There are 5 or more new aquatic species and Penaeus vannamei. In addition, a series of varieties have been continuously introduced, such as Jifu tilapia-Xinfu tilapia-Jili tilapia, Jianli-Jinxin carp-Jinxin carp No. 2,"Zhongke red" bay scallop-bay scallop "Zhongke No. 2","Penglai red" scallop-Chlamys farreri "Penglai red No. 2", kelp "Dongfang No. 1"-"Dongfang No. 2"-"Dongfang No. 3"-"Dongfang No. 6"-"Dongfang No. 7", Porphyra haitanensis "Shenfu No. 1"-"Shenfu No. 2"; Porphyra yezoensis "Sutong 1"-"Sutong 2"; Undaria pinnatifida "Haibao 1"-"Haibao 2" and so on.

Third, diversification of R & D subjects. Statistics show that the first breeding units of new varieties (including introduced species) basically cover the main research institutions of aquatic products industry in China, including scientific research institutes, aquatic colleges and universities, aquatic products promotion institutions, aquatic products enterprises, etc., with 80,40,7 and 29 respectively. The main body of R & D is mainly scientific research institutes and colleges and universities. In recent years, the participation of enterprises has increased. 93 varieties were independently cultivated by one unit, accounting for 60%; 63 varieties were jointly cultivated by two or more units, accounting for 40%; 14 varieties were jointly cultivated by three or more units, accounting for less than 10%.

Present Situation and Problems of Utilization of Introduced Species

China is one of the countries with the most introduced aquatic products. According to incomplete statistics, China has introduced more than 140 species of aquaculture, including more than 90 species of fish, more than 10 species of shrimp, more than 10 species of shellfish, more than 10 species of algae, more than 10 species of other species, and 30 species registered as new aquatic species. In addition, there are 23 new varieties developed directly from introduced species, which can be said that 1/3 of new aquatic varieties in China originate from introduced species. The introduction of aquatic fry plays an important role in promoting the development of aquaculture in China, among which tilapia, turbot, eel, white prawn, scallop (bay scallop and scallop yessoensis) have become important aquatic products in China, creating huge industrial value. In 2013, the cultivation output of tilapia in China reached 1,657,700 tons, and that of Penaeus vannamei reached 1,429,800 tons. Since 2009, the state has not identified introduced species.

Introduction promotes the development of aquaculture, but it cannot solve the fundamental problem of aquatic seed development in China. At present, illegal introduction is more than legal introduction, blind introduction is more than scientific demonstration, unquarantined introduction is more than disease prevention treatment, eager promotion is more than serious evaluation, repeated introduction is more than breeding. Introduction inevitably exists the following risks: First, introduction is controlled by others. Not only the price is controlled by monopoly, but also the introduced varieties generally show obvious degradation from the second generation and cannot continue to be used. The second is the threat of invasive alien species. At present, the aquatic invasive plants and animals that have shown harm include crayfish, crocodile, apple snail, water hyacinth, etc. The third is the problem of introduced species carrying parasites and diseases. It has been reported that many of the diseases causing heavy losses in aquaculture in China are caused by passively introduced viruses, such as shrimp white spot baculovirus and taura virus, flounder iridovirus, etc.

achievements promotion

At present, the main body of new aquatic product varieties promotion in China is basically centered on breeding units and oriented by market demand. The breeding unit directly or indirectly sells the seedlings of new varieties to farmers. The varieties with good breeding effect will be favored by farmers, which will stimulate the increase of seed sales and gradually expand the promotion effect. Jianli, Pengze crucian carp, Megalobrama amblycephala "Pujiang No. 1", Chinese prawn "Huanghai No. 1" and other varieties have been tested by breeding effect, and the promotion effect is good. Their popularity has been continuously improved, occupying a certain market, and their production contribution has been continuously improved. Every year, the Ministry of Agriculture will issue the main variety technology to guide all localities to further support the promotion of varieties that may have certain potential from the policy level. According to the investigation, there are still some varieties, because the breeding unit's own promotion ability limitation or variety specificity and other factors, after obtaining the new variety certificate, it will be shelved, unable to play the production effect.

Prospects for the development of new aquatic species

R & D challenges

Compared with planting and animal husbandry, aquaculture in China is still relatively backward, and compared with American channel catfish, South American white shrimp and Atlantic salmon industry in Norway, the gap is still very large. 55% coverage rate and 25% genetic improvement rate of aquatic varieties still have room for improvement. The development of modern aquatic seed industry is in urgent need of new aquatic varieties. However, at present, the research and development of new aquatic products in China faces some challenges. First, the status of aquatic germplasm resources is worrying. The deterioration of aquatic ecological environment and overfishing of natural fishery resources lead to the sharp decline of most aquatic biological resources and the decrease of genetic diversity. There were signs of germplasm degradation in the seed conservation resources. Second, the research and development foundation of improved varieties is still weak. The R & D of improved varieties needs continuous support of time, manpower and financial resources. Too many varieties weaken the strength of R & D investment of single varieties. In addition, there are still cultured species such as eel seedlings have not yet been artificially bred. Third, the hidden danger of relying on introduction. Fourth, there is a lack of resultant force among the cultivation subjects. There are many R & D units of a certain variety, multilateral cooperation is obviously lacking, scientific and technological resources are not well integrated, and joint efforts cannot be formed, resulting in waste of resources. Fifthly, the promotion of R & D achievements is insufficient. The cost of seed production or seedling production of new varieties is often higher than that of ordinary seedlings, and the quality advantage is often difficult to express. Generally, the common people only recognize the problem that the price of improved varieties causes the problem of high quality and low price, and the initial promotion of R & D achievements is difficult.

future prospects

On the road of building a modern aquaculture industry and becoming a powerful country in the world aquaculture industry, we must absorb all advanced technologies and experiences at home and abroad, and on the premise of strengthening the protection and rational development of germplasm resources, establish the concept of variety development and management in line with the characteristics of China's aquaculture industry, formulate long-term R & D and development plans for key aquaculture varieties, and strengthen the development, utilization and management of introduced species. Integrate social resources to gradually improve the systematic research and development and promotion of new varieties, and promote the improvement of major aquaculture species in a planned and focused manner, so as to realize the improvement of aquaculture and improve the competitiveness of China's aquaculture products in the international market. The author believes that in the future, we should focus on building and perfecting the following five systems on the basis of our existing work:

First, a systematic and perfect conservation system of aquatic germplasm resources.

Aquatic product breeding needs to be based on rich variety resources. Extensive collection and conservation of germplasm resources is of great value to the research and development of new aquatic products. At present, China has built germplasm resources protection areas, genetics and breeding centers and original improved seed farms to protect and preserve resources from the population, individual, cell, gene and other levels, but the whole system has not been formed. the information level of individual internal resource data is low, lack of horizontal and vertical contact with each other, and all kinds of resources can not be shared for the time being. In the future, the government should support the establishment of big data security platform to complete the linkage of the system and the allocation of resources. The system focuses on the collection and preservation of three types of resources: first, germplasm materials of existing leading breeding varieties and high-quality wild species; second, excellent germplasm materials such as disease resistance, cold resistance, saline-alkali tolerance and high protein; third, scientific research germplasm materials for basic research to maintain biodiversity.

The second is to clarify the policy support system for R & D main varieties.

Since the reform and opening up, due to the improvement of people's living standards and the development of market economy, the varieties of aquaculture have been increasing and becoming more and more diversified. However, the cultivation of R & D should take into account the needs of production development and the development trend of international aquaculture. At the national level, we should focus on establishing the main varieties for the cultivation and research and development of new varieties in China's aquatic seed industry, and vigorously support them to ensure the efficiency of the use of financial funds as far as possible. The establishment of the main varieties should be in line with the following principles: first, varieties that account for a certain proportion of the total output of aquaculture in China; second, the main consumer varieties in the domestic market; and third, export foreign exchange earning varieties. The author believes that the first batch of aquatic products research and development in China should include large yellow croaker, tilapia, turbot, eel, grass carp, common carp and crucian carp, Penaeus chinensis, Penaeus vannamei, swimming crab, river crab, shrimp scallop, bay scallop, oyster, clam, kelp and porphyra.

Third, perfect introduction, development, utilization and management system.

Establish and improve the national aquaculture variety introduction management system and information system. Strengthen the risk assessment of introduced species, strictly implement quarantine laws and regulations, and minimize the harm of alien species to China's germplasm resources. Carry on the whole process follow-up management to the new aquaculture varieties that have been introduced and to be introduced in China. According to the industrial development, formulate the medium-and long-term development plan to be introduced in the future. According to local conditions, the introduction of species will be digested and absorbed, re-innovated and popularized, and the protection of the local ecological environment will be paid attention to and strengthened.

Fourth, a new system of mature research and development of new varieties.

Break the pattern of individual combat and mutual competition, and adopt the strategy of combination of strong and strong forces and multi-disciplinary operations. Based on the national and market demand for germplasm utilization and aquaculture varieties, it is clear that the main direction is to cultivate high-yield, high-quality, disease-resistant, cold-resistant, saline-alkali resistant and high-density aquaculture varieties in facility fisheries. At the same time, the application basis and technology of breeding were studied. Each R & D team should include scientific research institutes, enterprises and promotion departments. Each unit performs its own duties, scientific research institutes are responsible for formulating technical routes and tackling difficult problems, enterprises are responsible for route implementation and feedback, and promotion departments are responsible for R & D, testing and feedback on market demand. The information of each breeding team is registered and disclosed by the national unified platform to ensure that the teams learn from each other and avoid resource conflicts.

Fifth, a complete new variety promotion system.

The state shall provide corresponding financial support for the promotion of new varieties to ensure that there will be funds for follow-up promotion after the announcement of new varieties. Establish a publicity system with sound channels, and make use of the Internet, television, books, newspapers, magazines and other media to extensively carry out publicity on new varieties and improve market awareness. Establish a step-by-step demonstration promotion base, take the national, provincial and prefectural (municipal) level extension station demonstration base as the main body, and carry out layer-by-layer demonstration and promotion of new varieties to ensure that the promotion industry plays a whole game of chess. Establish a technical guidance service center, extensively carry out new technology, new variety training and consultation on product after-sales issues. In addition, we will actively guide social forces to carry out cooperation in the promotion of improved varieties.