燕麦F_(1)代杂种优势及F_(2)代遗传变异分析

Assessing F_(1)Heterosis and F_(2)Genetic Variation in Oat:A Case Study

为了探讨燕麦正、反交杂种后代的杂种优势及遗传变异,本研究以引进品种爱沃和国产品种陇燕5号为亲本配制正、反交组合,对其F_(1)和F_(2)代的性状进行了观测,分析了其表型差异及杂种优势,探讨了F_(2)群体的遗传变异情况。结果表明,正、反交对F_(1)代的表型和杂种优势有显著影响,正交(爱沃(♀)×陇燕5号(♂),AL5)F_(1)代比反交(陇燕5号(♀)×爱沃(♂),L5A)早熟6 d,其株高、主穗粒数、千粒重和穗下节长显著大于反交,而旗叶长宽、倒二叶长均显著小于反交(P<0.05);正、反交F_(1)主穗长的超亲优势最大,分别为41.33%和31.92%,茎粗的超亲优势分别为−45.53%和−36.92%。F_(2)群体遗传变异幅度较大,分离现象明显。分蘖数和有效分蘖数的遗传变异系数和相对遗传进度最大,株高和茎粗的广义遗传率最高。叶片数和主穗粒数在正交和反交F_(2)中的遗传变异系数较为接近,但广义遗传率和相对遗传进度差异却很大。在F_(1)代超亲优势显著的茎粗和主穗长在F_(2)呈近似正态分布,正交F_(2)群体中有6.50%的个体主穗长的超亲优势大于30.00%,而反交主穗长的最大超亲优势为23.30%。总体而言,分蘖数、有效分蘖数具有较大的选择空间,株高、茎粗、主穗长等性状可在早代进行选择♂。

This study investigated the heterosis and genetic variation of oat hybrids derived from recip⁃rocal crosses between the introduced variety Everleaf(♀)and the domestic variety Longyan 5(♂).The phenotypic traits of were observed,and their heterosis were analyzed.The F_(1) and F_(2) generations were evaluated for phenotypic traits and heterosis,and genetic variation within the F_(2) population was analyzed.The results showed that reciprocal cross significantly impacted phenotypic traits and heterosis in the F_(1) gen⁃eration.The forward cross(Everleaf♀×Longyan5♂,AL5)matured 6 days earlier and had greater plant height,main spikelet number,thousand-grain weight,and peduncle length compared to the reverse cross(Longyan5♀×Everleaf♂,L5A).However,the forward cross exhibited lower flag leaf length and width,and penultimate leaf length(P<0.05).Both crosses displayed over-parent heterosis for panicle length,with 41.33%in the forward cross and 31.92%in the reverse cross.The lowest heterosis was obtained for stem diameter in both crosses(−45.53%and−36.92%,respectively).The F_(2) population exhibited wide genetic variation and segregation for most traits.Tiller number and effective tiller number had the highest coefficient of variation and relative genetic progress,while plant height and stem diameter had the highest heritability.Leaf and grain number of main panicle had similar coefficient of variation but differed in heritability and relative genetic progress.Traits with significant F_(1) heterosis(stem diameter and main panicle length)showed an approximately normal distribution in the F_(2) population.In the forward cross,6.50%of F_(2) plants exhibited over-parent heterosis for main panicle length exceeding 30.00%,com⁃pared to 23.30%in the reverse cross.In conclusion,the F_(2) population exhibited substantial genetic varia⁃tion,with tiller number and effective tiller number offering the greatest potential for selection.Early gen⁃eration selection for trait like plant height,stem diameter,and main panicle length may also be effective.