玉米杂种与亲本穗分化期功能叶基因差异表达与杂种优势

为探讨玉米杂种优势的分子机理，以10个玉米自交系及其组配的38个杂交种为材料，利用cDNA-AFLP技术，分析杂种与亲本在玉米雌穗小穗分化期功能叶片的基因差异表达类型与主要农艺性状的杂种表现及杂种优势的关系。研究表明：（1）杂种的基因相对于其双亲，存在质和量的表达差异，其中质的差异表达类型包括：单亲沉默表达，双亲沉默表达，亲本显性表达和杂种特异表达等类型。（2）在雌穗小穗分化期，同一差异表达类型中不同杂交组合间差异很大；从总体平均看，杂种特异表达类型占25.22%，亲本显性表达类型占21.46%，双亲沉默表达类型占8.27%，单亲沉默表达类型占33.49%。（3）单亲沉默表达与株高的杂种表现呈显著正相关；双亲沉默表达与穗粗的杂种优势呈显著负相关，显性表达与行粒数和单株粒重的杂种优势呈显著负相关，其余表达类型与所有农艺性状杂种表现及杂种优势均不相关，并对结果进行了讨论。

Relationship Between Differential Gene Expression Patterns in Functional Leaves of Maize Inbreds & Hybrids at Spikelet Differentiation Stage and Heterosis

To understand the molecular mechanism of maize heterosis,differential gene expression patterns in functional leaves between 10 maize inbreds and 38 hybrids at spikelet differentiation stage were analyzed by using cDNA AFLP.The correlation analysis of various differential gene expression patterns with the performance and heterosis of main maize agronomic traits was carried out.The main results are as follows:(1) There are differential gene expression patterns in quality and quantity between hybrids and their parents.The differential expression patterns in quality include:bands expressed only in one parent,bands expressed only in both parents,bands expressed only in one parent and F 1,bands expressed only in F 1.(2) At spikelet differentiation stage,there are large variations among different hybrids for the same differentially expressed patterns.In general from mean data,there were 25 22% bands expressed only in F 1,21 46% bands expressed in one parent and F 1,8 27% bands expressed only in both parents and 33 49% bands expressed only in one parent.(3) For bands expressed only in one parent,significant positive correlation was detected with the relationship to the performance of plant height.For bands expressed only in both parents,significant negative correlation was detected with the relationship to the heterosis of ear diameter.For bands expressed only in one parent and F 1,significant negative correlations were detected with the relationships to the heterosis of rows per ear and seed weight per ear.However,for bands expressed only in F 1,and for bands only in two parents or only in F 1,no significant correlation was detected with the relationship to the performance and heterosis of all agronomic traits.