基于SSR分子标记分析农家保护与种质库保存对云南地方稻种等位变异的影响

Effects of on-farm conservation and germplasm bank conservation on allelic variation in Yunnan local rice varieties based on SSR molecular marker analysis

  • 摘要: 【目的】基于SSR分子标记分析农家保护与种质库保存下云南地方稻种等位变异,以期分析农家保护与种质库保存方式对水稻种质资源多样性的影响,为地方稻种遗传多样性的有效保护及其保护途径选择提供理论依据。【方法】以种质库保存的12份地方稻种(命名为品种名-1)与其对应农家保护的地方稻种(命名为品种名-2)为试验材料,利用72个SSR分子标记对这24份地方稻种材料(共12组)进行遗传多样性及等位变异分析。【结果】供试24份地方稻材料共检测出等位基因数490个,变幅4~12个,平均6.8个,Nei’s基因多样性指数0.337~0.910,平均为0.769。农家保护的地方稻种较种质库保存的地方稻种等位基因数量、特有等位基因数量、有效等位基因数量均略低,但Nei’s基因多样性指数略高,表明农家保护的地方稻种遗传多样性略有降低。农家保护的小白糯-2和烂地谷-2分别在标记RM333和RM213上未检测出等位变异位点,小白糯-2、老粳糯-2和老鼠牙-2分别在标记RM349、RM18和RM333上检测出纯合等位变异位点,表明农家保护下部分等位位点流失。12组地方稻种材料间的遗传相似性系数为0.222~0.917,其中香谷的遗传相似性系数最高,小白糯的最低,在遗传相似系数为0.205处可将供试地方稻种材料聚类为籼、粳两大类,每组对应地方稻种材料均对应聚在一小类,表明供试对应地方稻种具有较高的遗传相似性且对应程度较高。24份地方稻种材料共检测出等位变异位点数260个,变幅6~57个,其中28个位点与抗逆相关,25个与育性相关,33个与抗病虫相关,26个与产量及营养相关,且农家保护下理论产量提高,表明农家保护下产生遗传变异可能是向着提高适应性来增加产量的方向发展。【结论】在农家保护下地方稻种的部分等位基因纯合与流失是其遗传多样性降低的内在原因,而其在育性、抗病虫、抗逆、产量及营养高效等功能连锁标记上产生大量的遗传变异,并呈株高降低、产量增加的变化趋势,增强了地方稻种应对自然生态环境和社会环境压力变化的能力,说明农家保护是地方稻种资源多样性保护的有效途径之一。

     

    Abstract: 【Objective】This study analyzed the allelic variation of corresponding local rice varieties under on-farm conservation and germplasm bank conservation by SSR markers,aiming to assess their impacts on the genetic diversity of rice germplasm resources. The findings would provide theoretical basis for the effective conservation of local varieties genetic diversity and the selection of preservation strategies. 【Method】Twelve germplasm bank conservation local varieties(Variety Name-1) and their corresponding on-farm conservation local varieties(Variety Name-2) were used as materials. A total of 24 local rice samples(12 pairs) were analyzed for genetic diversity and allelic variation using 72 SSR markers. 【Result】A total of 490 alleles were detected in the 24 samples,with a range of 4 to 12,and an average of 6.8. And the Nei’s gene diversity index ranged from 0.337 to 0.910,with an average of 0.769. The number of alleles,specific allele and effective alleles under on-farm conservation were slightly lower than germplasm bank conservation. However,Nei’s gene diversity index was marginally higher,indicating that the genetic diversity was slight decline under on-farm conservation. Xiaobainuo-2 and Landigu-2 exhibited no allelic variation sites at the markers RM333 and RM213 respectively under onfarm conservation. Xiaobainuo-2,Laojiangnuo-2 and Laoshuyua-2 displayed homozygous allelic variations at the markers RM349,RM18 and RM333 respectively, which revealed that the allelic variation sites would be lost under on-farm conservation. The genetic similarity coefficients among the 12 groups of local rice materials ranged from 0.222 to 0.917,with the highest in Xianggu and the lowest in Xiaobainuo. At a genetic similarity coefficient value of 0.205,the tested local rice materials could be clustered into indica and japonica categories,and each corresponding local rice materials further clustered into smaller categories,indicating a high degree of genetic similarity and correspondence among the tested varieties. A total of 260 allelic variation sites were detected among the 24 local rice materials,with a range of 6 to 57. Among these,28 were associated with stress resistance,25 with fertility,33 with disease and pest resistance,and 26 with yield and nutrition-related traits. And the theoretical yield has increased under on-farm conservation, it indicated that genetic variations produced under on-farm conservation might develop in the direction of enhancing adaptability to increase yield. 【Conclusion】Under on-farm conservation,the alleles homozygosity and loss of partial local rice varieties are intrinsic factors reducing genetic diversity. A large number of genetic variations are generated on functional linkage markers such as fertility,disease and insect resistance,stress tolerance,yield and nutrition efficiency, with change trends of reduced plant height and increased yield. The ability of local rice varieties to adapt to natural ecological and socio-environmental pressures are enhanced. It is indicated that on-farm conservation is one of the effective ways to protect the diversity of local rice resources.

     

/

返回文章
返回