雌穗膨大多行数玉米突变遗传性状鉴定评价

Genetic Character Identification and Evaluation of a Multi-row Maize Mutant with Expanded Female Ears

为鉴定、分析从广西亚热带玉米群体改良中收集的雌穗膨大多行数玉米材料的表型性状及遗传背景,通过调查该材料及其杂交再自交分离群体后代的雌穗部位农艺性状,利用F 2∶3分离群体分析其雌穗变异性状的遗传特性,制作幼嫩雌穗的石蜡切片和番红固绿染色,在光学显微镜下观察其细胞组织结构的形态变化,同时利用40对SSR标记和另外23份广西育种骨干自交系进行聚类分析,明确该批材料的遗传背景和杂种优势利用模式。结果表明,该多行数玉米材料雌穗变异性状具体表现出穗行数增加、果穗变粗、穗轴变粗、穗扁化和轴扁化5种主要特征,由多个QTL调控,其中2~3个QTL调控影响穗行数,基因间具有累加效应,通过调控幼嫩雌穗分生组织细胞过度发育使雌穗在生长过程中心皮相互挤压,形成扁化的穗轴和膨大的雌穗;通过聚类分析将25份样品划分为3个杂种优势群,本研究材料属于具有温-热混合血缘的改良瑞德种质。该雌穗膨大多行数玉米材料为新的未知基因变异,一方面可利用温-热×热杂种优势配对模式对其进行杂交组配,另一方面,可进一步挖掘其控制穗行数的QTL,进行分子标记辅助育种。

The phenotypic characters and genetic background were identified and analyzed in multi-row maize with excessively expanded ears collected from the subtropical maize population in Guangxi.To investigate the agronomic characters of the female ear of the multi-row maize and its progenies from the hybrid and self-crossing segregation populations,the F 2∶3 segregation population was used to analyze the genetic characteristics of the female ear variation.Paraffin section and safranine green staining were also performed on the young female ears,and the morphological changes of their cell and tissue structure were observed using the optical microscope.At the same time,cluster analysis was conducted on 40 pairs of SSR markers and 23 backbone selfbred lines used in breeding in Guangxi,with an aim to clarify the genetic background and the heterotic utilization mode of these samples.The results showed that variation characters of female ears of the multi-row maize showed five main characteristics,namely,increaseing rows per ear,thickened ears,thickened ear axes,flattened ears,and flattened ear axes.The variation characters of the female ears were regulated by multiple QTLs,2-3 of which had affected the number of rows per ear,and that genes presented an additive effect.The excessive development of meristem cells of the young female ears caused that the carpels extruded each other to form a flattened ear axis and an expanded female ears during the growth process.The 25 samples of the multi-row maize,which were divided into three heterotic groups through cluster analysis,belonged to the improved Reid germplasm with temperate-tropical mixed lineage.The expanded female ear were caused by mutation of new unknown genes.On the one hand,heterotic groups of temperate-tropical germplasm and tropical germplasm could be used for cross matching to breed new varieties.On the other hand,the QTLs controlling the number of rows per ear could be further explored for molecular marker-assisted selection.