基于SSR分子标记的多年生黑麦草杂交F_(1)代杂种鉴定

Identification of F_(1) Hybrids of Perennial Ryegrass Based on SSR Molecular Markers

多年生黑麦草是异花授粉植物,其杂交后代真假杂种的鉴定是进行杂交育种的重要前提。选用20对SSR引物对多年生黑麦草4个杂交组合的78个杂种F1代及4个亲本进行分析,每个杂交组合分别选择2对特异性SSR引物鉴定杂种F_(1)代的真实性。结果表明:筛选出的20对引物共扩增得到496条清晰条带,其中多态性条带351条,多态性比率70.77%;每个SSR位点的PIC值在35.86%~45.75%之间,均值为42.06%;4个杂交组合78个后代中共鉴定出72个真杂种,真杂种比率92.31%,其中杂交组合3(♀PI598517×♂Esquire)的真杂种率最高(95.83%),组合4(♀PI384479×♂PI598517)的真杂种率最低(85.71%),与聚类分析结果基本一致。20对SSR分子标记引物具有较高的多态性,可直接用于多年生黑麦草遗传多样性分析、杂种鉴定等相关研究,鉴定到的多年生黑麦草F_(1)代真杂种可为后续育种工作奠定基础。

Perennial ryegrass(Lolium perenne L.) is considered as a high-quality forage for livestock production and primary turf species with rapid growth and establishment, and generally post cross-pollinated characteristics. The identification of the true and false hybrids of its hybrid progenies is an important prerequisite for cross breeding. In this study, 20 pairs of SSR primers were used to analyze 4 parents and 78 F_(1) generation hybrids from four hybrid combinations of perennial ryegrass. Two pairs of specific SSR primers were selected for each hybrid combination to identify the authenticity of the F_(1) hybrids. The results showed that a total of 496 clear bands were obtained from 20 pairs of selected primers, including 351 polymorphic bands, with a polymorphism ratio of 70.77%. The PIC value of each SSR locus ranged from 35.86% to 45.75%, with an average of 42.06%. A total of 72 true hybrids were identified from 78 progeny of four hybrid combinations, and the true hybrid ratio was 92.31%. The true hybrid rate of hybrid combination 3(♀PI598517×♂Esquire) was the highest(95.83%), and that of hybrid combination 4(♀PI384479×♂PI598517) was the lowest(85.71%), which was consistent with the results of cluster analysis. 20 pairs of SSR marker primers screened in this study had high polymorphism and can be directly used in genetic diversity analysis and hybrid identification of perennial ryegrass. The identified F_(1) true hybrids of perennial ryegrass laid a foundation for subsequent breeding program of perennial ryegrass.