荻和南荻杂交种F_1群体主要农艺性状的杂种优势、遗传及相关性分析

Heterosis,genetic and correlation analysis of main agronomic traits in F_1 population derived from crossing between Miscanthus sacchariflorus and M.lutarioriparius

利用主要农艺性状上具有显著差异的荻和南荻为亲本,杂交得到种间杂交种F_1群体(232个单株)为试验材料,对荻和南荻杂交种茎节数、叶片长、叶宽、主茎长、花茎长、花序长、株高、基部茎径、平均单分蘖干重、最大分蘖干重、分蘖数和单株重等12个主要农艺性状的杂种优势进行了度量,采用主基因+多基因混合遗传模型对F_1杂交群体的12个主要农艺性状进行遗传和相关性分析。结果表明,在F_1分离群体中12个主要农艺性状呈连续的、单峰、偏态分布,说明这些性状为多基因控制的数量性状。除基部茎径外的其他11个农艺性状都有较大的中亲优势,其中单株重、平均单分蘖干重、花序长、主茎长、株高、最大分蘖干重具有显著的超高亲优势,说明杂种优势可以作为荻和南荻育种的主要方法。混合遗传分析表明,花茎长、最大茎重能检测到1对主基因,叶片宽、主茎长、株高、分蘖数、单茎均重、单株重能检测到2对主基因的存在,主基因遗传率大小顺序为叶片宽(87.76%)>单株重(81.48%)>单茎均重(65.12%)>分蘖数(59.20%)>主茎长(49.87%)>株高(48.01%)>花茎长(47.75%)>分蘖最大茎重(37.19%)。产量相关性状中的单株重、单茎均重和分蘖数具有较高的主基因遗传率,适合于早期世代选择。这12个农艺性状间存在一定的相关性,多数性状间的相关性为极显著的正相关,其中单株重与分蘖数、单茎均重、主茎长和株高的相关系数最大,在育种实践中可以利用相关性状进行间接选择。

A F_1 population with 232 individuals was developed from a cross between Miscanthus sacchariflorus and M.lutarioriparius,two Miscanthus species significantly different in the main agronomic traits.A total of 12 traits including the number of nod（Non）,the length of leaf（Lol）,the width of leaf（Wol）,the length of main stem（Lms）,the length of flower stalk（Lfs）,the length of inflorescence（Loi）,the plant height（Ph）,the basal stem diameter（Sd）,the number of tillers（Not）,the average dry weight of single tiller（Wsl）,the average dry weight of the biggest single tiller（Wbt）,the weight of individual plant（Wop）were determined,and then subjected to genetic and correlation analysis using a mixed major gene plus polygene inheritance model.The results showed that each of trait produced a continuous,single peak and skewed distribution pattern,suggesting that they are quantitative traits.Except for the stem diameter（Sd）,the other 11 traits exhibited a mid-parent heterosis,especially in which the Wop,Wsl,Loi,Not,Lms,Ph and Wbt even exhibited a heterobeltiosis,which indicates that the hybrid heterosis would be a major breeding method for Miscanthus.In addition,the mixed factors genetic analysis indicated that the performance of Lfs and Wbt might be controlled by a pair of major genes,and those of Wol,Lms,Ph,Not,Wsl and Wop by 2pairs of major genes.The orders of the heritability of major genes for each trait are as follows：Wol（87.76%）Wsl（81.48%）Wop（65.12%）Not（59.20%）Lms（49.87%）Ph（48.01%）Lfs（47.75%） Wbt（37.19%）.Some yield-related traits comprising‘Wop＇,‘Wsl＇and‘Not＇are suitable to be selected in early generation because they are with a higher major gene effect.Correlation analysis among traits revealed that Wop is positively correlated with Non,Lms,Ph,Sd,Not,Wsl,and Wbt.Of those,Not,Wsl,Lms and Ph gave the highest correlation with Wop,and thus these traits could be selected indirectly according to their related trait performance in breeding practice.