甜玉米南方锈病抗性配合力及遗传特性分析

Analysis of Combining Ability and Genetic Characteristics of Sweet Corn Southern Rust Resistance

对甜玉米南方锈病抗性配合力及遗传特性进行分析,为抗病育种提供理论依据。从6个遗传差异较大的自交系,按照GriffingⅡ双列杂交设计,通过Photoshop CS5软件进行叶片病斑识别和病斑面积分割,分别得出叶片和病斑的像素值,以穗三叶病斑叶面积比作为鉴定指标,对南方锈病性状配合力及遗传参数进行分析。应用图像分析软件识别叶片病斑可相对精确地进行玉米南方锈病抗性的鉴定与量化。6个亲本一般配合力效应存在较大的差异,大小排序为:M114-1>M3-1>M4-1>M55-1>M119-1>M5-1,不同组合间的特殊配合力也存在显著差异,结合一般配合力及效应值与其他亲本杂交后的特殊配合力遗传变量,对自交系利用价值综合评价,表明自交系M119-1能将抗南方锈病的性状稳定地遗传给所有的组合,是较为理想的抗南方锈病自交系,在育种中应对其加以有效利用。南方锈病以非加性效应为主,甜玉米南方锈病广义遗传率为89.88%,狭义遗传率为6.70%,说明抗南方锈病性状受环境的影响较小,加性效应很低,应在高代选择。本研究克服了传统抗性鉴定只能获得分级间断型数据的缺点,利用图像分析软件,可以相对连续、精确、客观地统计玉米南方锈病抗性。并对南方锈病性状配合力及遗传参数进行分析,提高育种实践的选择效果与效率。

The resistance combining ability and genetic characteristics of southern rust disease in sweet corn were analyzed to provide a theoretical basis for disease resistance breeding.Six inbred lines with large genetic differences were designed according to GriffingⅡdual-column hybridization.Leaf lesion spot identification and lesion area segmentation were performed by Photoshop CS5 software,and the pixel values of leaves and lesion spots were obtained respectively.Leaf area ratio was used as an identification index to analyse the combining ability and genetic parameters of southern rust traits.Identification of leaf lesions using image analysis software could be used to relatively accurately identify and quantify the resistance to southern corn rust.There was a large difference in the general combining ability effect of the six parents.The size order was:M114-1>M3-1>M4-1>M55-1>M119-1>M5-1.There were also significant special combining forces among different combinations.The difference,combined with the general combining ability and the effect value of the special combining ability genetic variables after crossing with other parents,comprehensive evaluation of the use value of the inbred line showed that the inbred line M119-1 could inherit the traits resistant to southern rust stably to all combination was an ideal inbred line resistant to southern rust,which should be used effectively in breeding.Southern rust was dominated by non-additive effects.The generalized heritability of southern rust in sweet corn was 89.88%,and the narrowly inherited rate was 6.70%.This indicates that the resistance to southern rust is less affected by the environment and the additive effect is low.This study overcomes the shortcoming that traditional resistance identification can only obtain graded discontinuous data.Using image analysis software,it is possible to relatively continuously,accurately,and objectively statistic the southern corn rust resistance.The analysis of combining ability and genetic parameters of southern rust traits can improve the selection effect and efficiency of breeding practice.