青黑杨杂种全同胞二倍体与三倍体长枝叶性状变异研究

Variation in leaf traits on long branches in full-sib diploid and triploid hybrids between section Tacamahaca and sect.Aigeiros of Populus

【目的】探明青黑杨杂种全同胞二倍体与三倍体植株的扦插苗长枝叶叶片和气孔性状的遗传变异规律,解析基因型效应和倍性效应对长枝叶性状的影响。【方法】以‘哲引3号杨’ב北京杨’杂种全同胞二倍体和三倍体扦插苗为材料,对其长枝叶叶片和气孔性状的变异情况进行分析。【结果】长枝叶叶片长度、叶片宽度、叶片长宽比、叶面积、叶柄长度、叶绿素含量、气孔长度、气孔宽度、气孔密度等性状在不同基因型间存在极显著差异,各性状的变异系数范围为8.54%~36.20%,重复力介于0.645~0.916之间,表明叶片及气孔性状受到较强的遗传控制。三倍体群体叶片的叶绿素含量极显著高于二倍体,气孔长度、气孔宽度极显著大于二倍体,气孔密度极显著小于二倍体,而不同倍性群体间其他叶片各性状间未发现显著性差异。尽管如此,并非所有的三倍体基因型均显示出更优的性状表现。相关性分析显示,叶片长度与叶片宽度、叶面积和叶柄长度间相互均呈极显著正相关;叶绿素含量、气孔长度和气孔宽度间相互呈极显著正相关,均与气孔密度呈极显著负相关。进一步分析发现,叶片长度、叶片宽度、叶面积、叶柄长度等叶片性状主要受基因型效应影响,其基因型方差贡献率在59.5%~76.8%之间,叶绿素含量和气孔长度、气孔宽度、气孔密度等性状主要受倍性效应所影响,其倍性效应方差贡献率在46.0%~78.0%之间。【结论】青黑杨杂种全同胞二倍体及三倍体5月龄扦插苗长枝叶叶片和气孔性状受到不同程度的基因型效应和倍性效应的共同影响,基因型间存在丰富的性状变异,三倍体也并非株株皆优,杨树异源三倍体育种需秉持“大群体,强选择”理念。

[Objective]This study aimed to investigate the variations on leaf and stomatal traits of long branch leaves in the full-sib diploid and triploid hybrids between sections Tacamahaca and Aigeiros of Populus,and to analyze the genotype and ploidy effects on the traits.[Method]Cuttings of the full-sib diploid and triploid hybrids between P.pseudo-simonii×P.nigra‘Zheyin3#’and P.×beijingensis were randomly selected to investigate variations on leaf and stomatal traits of the long branch leaves.[Result]The leaf length(LL),leaf width(LW),leaf length-width ratio(LWR),leaf area(LA),petiole length(PL),chlorophyll content(SPAD),stomatal length(SL),stomatal width(SW),and stomatal density(SD)exhibited highly significant differences among different genotypes.The coefficient of variations for each trait ranged from 8.54%to 36.20%,and their repeatability values of these traits ranged from 0.645 to 0.916,indicating that the leaf and stomatal traits were controlled by strong heredity.The SPAD,SL and SW of the triploid population were significantly higher than those of the diploid population,and the SD was significantly lower than that of diploids,but there were no significant differences in leaf traits between different ploidy levels.However,not all triploid genotypes showed better performance on these traits than diploids.The correlation analysis showed that LL,LW,LA and PL were significantly positively correlated with each other.The SPAD,SL and SW were also positively correlated with each other,but negatively correlated with SD.Further analysis showed that leaf traits,such as LL,LW,LA,and PL,were mainly affected by the genotype effect,which contributed 59.5%-76.8%of the variance contribution rate for these traits.The SPAD,SL,SW,and SD were mainly affected by the ploidy effect,and the variance contribution rate of the ploidy effect for these traits ranged from 46.0%to 78.0%.[Conclusion]Leaf and stomatal traits of the long branch leaves in 5-month-old cuttings of the full-sib diploid and triploid hybrids between sects.Tacamahaca and Aigeiros of Populus are affected by both genotype and ploidy effects with different degrees.There are large variations in leaf and stomatal traits among genotypes,and not all triploids are excellent.Therefore,the idea of“large population,strong selection”should be adhered to allotriploid breeding program in Populus.