割手密遗传作图最适分离群体的选择

目的]筛选适合用于构建割手密遗传连锁图谱的分离群体,为后续的遗传连锁图谱构建和基因定位及遗传育种提供理论依据.方法]基于“双假测交“理论,利用DNA水平上遗传差异较大且蔗糖分和分蘖率差异极显著的不同割手密无性系进行杂交获得3个不同杂交组合,对3个备选作图群体的分蘖率和蔗糖分进行变异、正态分布拟合分析及分子多态性分析.结果]组合3（GXS85-12×GXS87-16）和组合13（云割①×田林）的分蘖率呈偏态分布,而组合5（GXS85-30×GXS87-16）的分蘖率呈近似正态分布;组合3和组合5的蔗糖分呈偏态分布,而组合13的蔗糖分呈近似正态分布.在分子多态性水平上,组合5亲本的遗传相似系数略高于组合3和组合13,而其后代平均遗传相似系数略低,但变幅较高.结论]组合5（GXS85-30×GXS87-16,群体大小为245株）的分蘖率、蔗糖分遗传性相对稳定,群体来源比较广泛,分子多态性丰富,遗传多样性高,可作为分离群体用于构建遗传图谱.

Segregation population selection for genetic linkage maps in Saccharum spontaneum L.

Objective]The optimal segregation population for genetic linkage map in Saccharum spontaneum L. was constructed to provide theoretical references for follow-up construction of genetic linkage maps, gene mapping and genetic breeding. Method]Based on double pseudo-testcross format theory, Saccharum spontaneum L. clones with more genetic divergence at the DNA level and extremely significant difference on the sugar content and tillering rate were used for hy- brid access to 3 different cross combinations. The tillering rate and sucrose content of the three candidate mapping popula- tions were analyzed for their variation, normal distribution fitting and molecule polymorphism. Result]The tillering rate of combination 3（GXS85-12×GXS87-16） and 13（Yunge①×Tianlin） showed skew distribution, while combination 5 showed approximating normal distribution. The sugar content of combination 3 and 5 （GXS85-12xGXS87-16） showed skew distri- bution, while combination 13 showed approximating normal distribution. On molecular polymorphism level, the parents combinations genetic similarity coefficient of combination 5 with higher variable amplitude was slightly higher than that of combination 3 and 13, but the offspring average genetic similarity coefficient （GS） was lower than the other two. Conclu- sion]The combination 5 （GXS85-30xGXS87-16,245 strains） had comparatively hereditary stability in tillering rate and sugar content, wide source population, rich molecular polymorphism and high genetic diversity, hence it could be used as segregation population for genetic maps.