海带单倍体克隆育种和育苗生物技术的研究

IOCAS-IR > 海洋环流与波动重点实验室

	海带单倍体克隆育种和育苗生物技术的研究
	李大鹏
学位类型	博士
	1999
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
学位专业	海洋生物学
关键词	海带配子体克隆育种育苗
摘要	以优良的海带品种为试材，分离、培养、建立了它们的单倍体（配子体）克隆无性繁殖系；对配子体克隆的生长及发育特性进行了研究；建立了海带配子体克隆丰富培养的模式。根据其生长和发育特性进行了海带单倍体克隆育种和育苗生物技术的研究。建立了利用海带配子体克隆将育种和育苗结合起来的新技术，其内容主要包括：建立优良品系海带的配子体克隆无性系；进行多组合杂交，筛选具有优良性状的F＿1代孢子体；丰富培养具有优良性状孢子体的亲代的雌雄配子体克隆；利用大量的雌雄配子体克隆进行种苗生产。在本项研究中，利用优良的海带单克隆无性系进行了多组合的交配，在海上进行了2年的养殖实验，以叶长、鲜重、碘含量等经济性状为指标进行了品系筛选工作，获得了产量高于对照（养殖品系）10.8％的品系Wh860♀* Lid ♂及碘含量高于对照55%的品系Wh860♀ * Rong♂。成熟孢子体的测量结果表明，同一交配组合中孢子体形态非常一致，不同的交配组合孢子体形态差异显著。通过对成熟孢子体性状的遗传性分析证实了利用海带配子体克隆培育的孢子体比常规育苗方法培育的孢子体性状分离度小，可有效保持品系遗传纯度；实验结果证明了利用海带配子体克隆育种是可行而有效的。利用选育的海带配子体克隆成功地进行生产性育种和育苗，结果表明，通过这种育种技术可使育种时间由传统的5－6年缩短至2年，并使新品系易于推广。该育苗技术可使育苗时间由原来的3－4个月缩短至1.5个月左右，可大幅度降低成本，并在一定程度上减少病害的发生。该项技术的成功对海带传统育种和育苗技术的革新具有重要意义。
其他摘要	At present, the total annual production of cultured Laminaria japonica has reached half million tons dry weight in China. In L.japonica cultivation industry, good strains and healthy sporelings are keys to success of cultivation. Almost all of the harvest in China comes from genetically improved strains. Genetic improvement of L.japonica was first initiated in China in the late 1950's. At first, Chinese phycologist exploited the selection plus intensive inbreeding method to develop two improved strains, Haiqing No.1 and Haiqing No.2 Somewhat later, two additional new varieties Nos 860 and 1170 were bred through inbreeding and selection method. These strains contributed substantially to Chinese L.japonica cultivation industry, but they have been losing their economic characteristics in the course of extension to farms. That is due to mixed zoospore collection from thousands of parent plants generation after generation. Moreover, the method by which they are bred takes too much time (generally 5-6 years) to meet the demand of production. The routine sporeling raising method of L.japonica is to collect zoospore in summer. The gametophyte and resultant young sporophyte are cultured at 6-10 ℃ with an irradiance of 60-100 μ mol m~(-2)s~(-1) in green house. After some 3.5 months culture in green house, the sporelings are transplanted to open sea. Long term cultivation in green house with low temperature is very expensive and laborious and the sporelings are inevitably attacked by diseases. In order to overcome the above-mentioned shortcomings, a new technique combining strain selection with sporeling raising by the use of gametophyte clones was designed. It involves five steps: 1. isolation of single female and male gametophytes and induction of gametophyte colones; 2. crossing of female and male gametophytes of different lines; 3. selection of adult sporophytes; 4. mass culture of the female and male gametophyte clones which give rise to the selected sporophyte; 5. sporeling raising by the use of the same female and male gametophyte clones. In this study, one-celled female and male gametophytes of L. japonica were isolated, cultured and gametophyte clones were formed. Growth and development properties of female and male gametophyte clones were investigated. On the basis of knowledge of growth and development of gametophyte clones, Strain selection and sporeling raising by the use of gametophyte clones were carried out. Experiment on 14 different crossing combinations was conducted. Main economic characteristics, frond length, fresh weight and iodine content, of F_1 sporophyte of different combinations were measured. The result showed, there were significant differences in morphology among different combination, and sporophytes in the same combination were almost morphologically uniform. Since the cultural conditions for sporophytes of different combinations were almost the same both in lab culture and open sea cultivation, the facts that there were significant differences among combinations and similarities in the same combination in frond length and fresh weight should be mainly attributable to genetic factors. F1 sporophytes of No. 1 and No. 2 showed a higher average fresh weight and longer frond length, therefore, No. Wh (♀ * ♂) and No. 2 (Wh860 ♀ * Lid♂) were selected as good combinations. Their parental female and male gametophyte clones were mass cultured for sporeling production. Experiment on sporeling production by this technique showed, as compared with the routine method of sporeling raising, the time of sporeling raising by this technique decrease by 50%, consequently, the production cost is half cut too. Besides, short term cultivation of sporelings in a greenhouse will decrease the possibility of being attacked by malformation and sporeling detachment diseases. Statistic data from large-scale cultivation showed, sporophytes produced by the new technique have less morphological variation than the control. This is taken to mean that, the use of gametophyte clones, which can be propagated vegetatively under controlled condition as genetically identical "seeds" can solve the problem of segregation of economic characteristics. Through screening, the desired combination of female and male gametophyte clones can be purposely chosen in 2 years; The parental gametophyte clones can be kept as stock in lab, and mass culture can be made in time of need for sporeling production on large scale. In the following years, the same combination of gametophyte clones could be used again and therefore the original characteristics of sporophytes could be conserved well. Sporelings used for commercial cultivation are produced by random fusion of gametes released from unrelated gametophyte derived from thousands of individual parent sporophytes, it was assumed that the cultivated strains, which had not been subjected to any further systematic selection generation after generation, would have a high degree of heterozygosity. This is taken to mean that some of the economic characteristics would lose several generations extension to Laminaria farms. The extension work of 860 and 1170 which bred in the seventies proved that this is true. In case of using gametophyte clones for strain selection and sporeling rainsing, the resulting F1 sporophytes would have little segregation from parents and attained more homogeneity. Through 2 years breeding work, one strain with more 10.8% production and another higher 55% iodine content than the control were selected out. In conclusion, the new technique has the following advantages: 1. combine strain selection with sporeling raising; 2. shorten the time of strain selection from 5-6 to 2 years; 3. decrease the time of sporeling raising from 3-4 months to 1.5 month or so; 4. keep selected strain from continual segregation; 5. the sporelings can be raised any time all the year round. It is believed that this technique will be a labor and time saving and more economic way for strain selection and sporeling raising in L.japonica cultivation industry.
页数	76
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/673
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	李大鹏. 海带单倍体克隆育种和育苗生物技术的研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,1999.

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