烤烟上部叶叶面积相关性状的遗传及杂种优势分析

Genetic and heterosis analysis of leaf area related traits in upper leaf of flue-cured tobacco

【目的】探讨不同烤烟品种(系)上部叶叶面积相关性状的配合力及其杂种优势表现,为选育上部叶开片良好的烤烟杂交种提供亲本选配依据和组合选择技术。【方法】以叶面积差异明显的8个烤烟品种(系)为亲本,采用NCⅡ遗传设计组配16个杂交组合,打顶前测定各亲本及杂交组合的自然株高和自然叶片数,打顶后7 d测定株高及顶上部往下5片烟叶的叶长和叶宽,计算叶面积,并分析上部叶叶面积相关性状的遗传及其杂种优势表现。【结果】亲本间和杂交组合间的上部叶叶面积及相关性状存在真实的遗传差异。叶面积与自然叶片数、叶长和叶宽呈显著(P<0.05)或极显著(P<0.01)正相关,相关系数分别为0.26、0.87和0.94;烤烟自然叶片数、叶长、叶宽及叶面积性状的广义遗传率高,分别为83.91%、66.33%、52.22%、50.67%,其中叶长和叶面积主要受加性效应基因的影响,而叶宽和叶片数受非加性效应基因的影响较大。对于一般配合力(GCA)和特殊配合力(SCA),自然叶片数性状中最大的分别是南江3号(3.64)和G28×南江3号(5.70);叶宽性状中最大的分别是G28(7.06)和G28×韭菜坪2号(10.91);叶面积性状中最大的分别是毕纳1号(12.54)和G28×韭菜坪2号(13.63)。G28×韭菜坪2号的叶宽和叶面积性状及G28×南江3号的自然叶片数均表现为正向的超亲优势和超标优势。【结论】通过优势育种改良烤烟上部叶开片时要重视上部叶片叶宽和自然叶片数2个性状的有效利用。毕纳1号、G28和南江3号是改良烤烟上部叶开片度的优良亲本,G28×韭菜坪2号、G28×南江3号和Va116×毕纳1号的特殊配合力、超亲优势和超标优势值大,是上部叶开片较好的优良杂交组合,有较大的应用潜力。

【Objective】To explore the combining ability and heterosis performance of the upper leaf area related traits of different flue-cured tobacco varieties(lines),and to provide the basis for parent selection and combination selection techniques for breeding flue-cured tobacco hybrids with good upper leaf slices.【Method】In this study,eight flue-cured tobacco varieties(lines)with obvious difference in leaf area were used as parents and 16 hybrid combinations were NCⅡgenetic design.Before topping,the natural plant height and the natural leaf number of each parent and hybrid combination were measured,and plant height,the leaf length and leaf width of five tobacco leaves from the top to the bottom were determined 7 d after topping.And the inheritance and heterosis of leaf area related characters in upper leaf were analyzed.【Result】There were real genetic differences in leaf area of upper leaves and related characters between parents and hybrid combinations.Significant(P<0.05)or extremely significant(P<0.01)positive correlation were found between leaf area and natural leaf number,length and leaf width.The correlation coefficients were 0.26,0.87 and 0.94,respectively.The broad-sense heritability of natural leaf number and leaf length,leaf width characters of flue-cured tobacco were high,being 83.91%,66.33%,52.22%and 50.67%,respectively.Leaf length and leaf area were mainly affected by additive effect genes,while leaf width and leaf number were mainly affected by non-additive effect genes.For general combining ability(GCA)and special combining ability(SCA)values,Nanjiang No.3(3.64)and G28×Nanjiang No.3(5.70)were the largest in natural leaf number traits,G28(7.06)and G28×Jiucaiping No.2(10.91)were the largest in leaf width,Bina No.1(12.54)and G28×Jiucaiping No.2(13.63)were the largest in leaf area traits.The leaf width and leaf area characters of G28×Jiucaiping No.2 combination and the natural leaf number of G28×Nanjiang No.3 combination showed positive overparent and over-standard advantage.【Conclusion】When improving upper leaf opening degree by advantageous breeding,upper leaf width and natural leaf number should be utilized effectively.Bina No.1,G28 and Nangjiang No.3 are excellent parents in improving the upper leaf opening degree of flue-cured tobacco.G28×Jiucaiping No.2,G28×Nangjiang No.3,Va116×Bina No.1 enjoy special combining ability,over-parent and over-standard advantages.It is a good hybrid combination with good upper leaf opening,and has great application potential.