甘蓝型油菜株高及其相关性状的主基因+多基因遗传分析

摘要

油菜株高对产量、抗逆性尤其是抗倒伏性有重要影响,适当降低株高可提高油菜抗性和收获指数进而提高产量.甘蓝型油菜(Brassica napus L.)矮秆自交系‘74-1002’具有早熟、分枝多、抗倒伏等优良性状,是进行油菜株高遗传和矮化育种的良好材料.以高秆甘蓝型油菜自交系‘HN92’为母本,‘74-1002’为父本,杂交构建6世代遗传群体(P1、P2、F1、F2、B1和B2),对6世代群体的株高及其相关性状进行度量,采用主基因+多基因混合遗传模型进行遗传分析.结果表明:株高(PH)、主花序长度(MIL)及一次有效分枝高度(VBH)均受到2对加性主基因控制,并存在加性—显性多基因效应,PH和MIL的最适遗传模型为E-0模型(MX2-ADI-ADI),VBH的最适遗传模型为E-3模型(MX2-A-AD);有效分枝节间距(IL)和有效分枝数(BN)的遗传均只受加性—显性—上位多基因控制,无主基因效应,其最适遗传模型为C-0模型(PG-ADI).在B1、B2和F2世代中,PH的主基因+多基因遗传率最高,分别为71.22％、78.71％、81.87％;其次是VBH和MIL,分离世代主基因+多基因平均遗传率分别为57.10％和44.09％;IL和BN的遗传率偏低,3个世代主基因+多基因平均遗传率分别为15.24％和9.68％.相关性分析表明:PH与VBH、MIL和IL的相关性表现为极显著的正相关,相关系数分别为0.533、0.721和0.520.因此,在甘蓝型油菜理想株高育种进程中,在旱代对株高进行选择是有效的,该研究也为后期开展株高相关性状QTL分析奠定基础,有利于加快油菜株高分子标记辅助育种进程.%Plant height of rapeseed plays an important role in yield and resistance,especially the lodging resistance.The yield can be increased through increasing harvest index and resistance,which can be realized by reducing the plant height properly.The dwarf inbred line,'74-1002',with traits of early maturity,multiple valid branches and lodging resistance,is a suitable material for rapeseed breeding.In this study,'74-1002'was served as male parent and'HN92',another inbred line of Brassica napus L.with high plant height,was treated as female parent.Six generations (P1,P2,F1,F2,B1 and B2) derived from'HN92'×'74-1002'were used to measure the plant height related traits,and their inheritances were analyzed by mixed major gene plus poly-gene genetic model.Results showed that plant height (PH),first valid branch height(VBH) and main inflorescence length (MIL) were dominated by two pairs of additive major gene plus poly-gene with additive-dominant effects.PH and MIL were fitted the model of E-0 (MX2-ADI-ADI) while first valid branch height (VBH) was fitted the model of E-3 (MX2-A-AD).Internodal length(IL) and the numbers of valid branch(BN) were dominated by additive-dominant-epistatic poly-gene without major-gene effect and were fitted the model of C-0 (PG-ADI).The heritabilities among segregating generations(B1,B2 and F2) of PH reached the highest,which were 71.22％,78.71％ and 81.87％ respectively,and were followed by the heritabilities of VBH and MIL,which were 57.10％ and 44.09％ on average.The heritabilities of IL and BN were much lower and were 15.24％ and 9.68％ on average.The correlation analysis showed that PH was significantly and positively correlated with VBH,MIL and IL,and the correlation coefficients were 0.533,0.721 and 0.520 respectively.To sum up,in the breeding process of ideal plant height in Brassica napus L.,the selection of plant height was effective in early generation.Also the study we made laid the foundation for QTL analysis of plant height relevant traits and was helpful to accelerate the progress of marker assisted breeding on rapeseed height.