标准切花菊杂交F1代群体侧枝侧蕾性状的杂种优势和遗传分析

以标准切花菊〔Dendranthema morifolium(Ramat.)Tzvel.〕品种'优香'('Yuuka')为母本、品种'神马'('Jinba')为父本进行杂交,对杂交F1代群体的单株侧枝平均长度、单株侧枝数、单株侧枝数与单株叶节数的比值(R1)、主蕾直径与侧蕾直径的比值(R2)、单株侧蕾数以及主蕾与侧蕾间距离6个性状进行杂种优势和相关性分析,并利用主基因+多基因混合遗传模型检测这些性状的主基因效应.结果显示:杂交F1代群体6个侧枝侧蕾性状的变异系数为2378%~5065%,且侧枝性状的变异系数总体上高于侧蕾性状;各性状的频次均呈现连续性的正态分布趋势,说明这些性状可能属于多基因控制的数量性状.杂交F1代群体的6个侧枝侧蕾性状均在001水平上表现出显著的中亲优势,表明各性状均存在显著的杂种优势.6个性状中,单株侧枝平均长度的中亲值最大(6230 mm),R1的中亲值最小(026);单株侧枝平均长度、R2和主蕾与侧蕾间距离的中亲优势均为正值,单株侧枝数、单株侧蕾数和R1的中亲优势均为负值.6个性状的中亲优势率为-5374%~3128%,其中,单株侧枝数的中亲优势率最小,而主蕾与侧蕾间距离的中亲优势率最大.相关性分析结果显示:单株侧枝平均长度和单株侧枝数均与R1呈极显著正相关,并与R2和单株侧蕾数呈极显著负相关;R2与侧蕾数也呈极显著正相关,且二者均与主蕾与侧蕾间距离呈极显著正相关.混合遗传分析结果显示:单株侧枝平均长度、R1、R2和单株侧蕾数均受2对主基因控制,符合B-1模型,主基因表现为"加性-显性-上位性",这4个性状的遗传率分别为7707%、9672%、6438%和5307%;单株侧枝数也受2对主基因控制,符合B-2模型,主基因表现为"加性-显性",该性状的遗传率为7438%,表明这5个性状的遗传存在主基因控制效应.而主蕾与侧蕾间距离符合A-0遗传模型,说明该性状无主基因控制,易受环境影响.

Analyses on heterosis and genetics of lateral branch and lateral flower bud traits of crossbred F1 group of standard cut chrysanthemum ( Dendranthema morifolium )

Taking cultivar 'Yuuka'as female parent and cultivar'Jinba' as male parent of standard cut chrysanthemum 〔Dendranthema morifolium ( Ramat.) Tzvel.〕 for hybridization, analyses on heterosis and correlation of six traits including average length of lateral branch per plant, lateral branch number per plant, ratio of lateral branch number per plant to leaf internode number per plant (R1), ratio of main flower bud diameter to lateral flower bud diameter ( R2 ) , lateral flower bud number per plant and distance between main flower bud and lateral flower bud of crossbred F1 group were investigated. The major gene+polygene mixed genetic model was used to explore the major gene effect among these traits. The results show that the coefficient of variation of six traits of lateral branch and lateral flower bud of crossbred F1 group is 2378%-5065%, and that of lateral branch is generally higher than that of lateral flower bud. The frequency of each trait shows a continuous normal distribution trend, indicating that these traits belong to quantitative traits controlled by multiple genes. Six traits of lateral branch and lateral flower bud of crossbred F1 group all appear the significant mid?parent heteroses at 001 level, showing that there is a significant heterosis in each trait. Among six traits, the mid?parent value of average length of lateral branch per plant is the largest (6230 mm), and that of R1 is the smallest (026). The mid?parent heteroses of average length of lateral branch per plant, R2 and distance between main flower bud and lateral flower bud are positive, while those of lateral branch number per plant, lateral flower bud number per plant and R1 are negative. The ratio of mid?parent heterosis of six traits is -5374% -3128%, in which, that of lateral branch number per plant is the smallest and that of distance between main flower bud and lateral flower bud is the largest. The result of correlation analysis shows that average length of lateral branch per plant and lateral branch number per plant have extremely significantly positive correlations with R1, and have extremely significantly negative correlations with R2 and lateral flower bud number per plant. R2 also has an extremely significantly positive correlation with lateral flower bud number per plant, and both of them have extremely significantly positive correlations with distance between main flower bud and lateral flower bud. The mixed genetic analysis result shows that average length of lateral branch per plant, R1, R2 and lateral flower bud number per plant are controlled by two pairs of major genes which confirm to B?1 model, their major genes display "additivity?dominance?epistasis", the heritability values of these four traits are 7707%, 9672%, 6438% and 5307%, respectively. Lateral branch number per plant is also controlled by two pairs of major genes which confirms to B?2 model, its major genes display"additivity?dominance", and the heritability value of this trait is 7438%. It is indicated that the inheritance of these five traits has major gene control effect. While distance between main flower bud and lateral flower bud confirms to A?0 model, indicating that this trait is not controlled by major gene and is easily affected by environment.