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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 2 5 2 2 % ,亲本显性表达类型占 2 1 4 6 % ,双亲沉默表达类型占 8 2 7% ,单亲沉默表达类型占 33 4 9%。 (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
In order to explore the molecular mechanism of heterosis in maize, 10 maize inbred lines and 38 hybrids were used as materials. The genetic differences of functional leaves between hybrids and their parents in spikelet differentiation of maize were analyzed by cDNA AFLP Relationship between Expression Type and Hybrid Performance and Heterosis in Main Agronomic Traits. The results showed that: (1) There are some differences in the quality and quantity of the genes of the hybrids relative to their parents. The types of differential expression include the single-parent silent expression, the silent parental expression, the dominant expression and the hybrid-specific expression. (2) In the spikelet differentiation stage, there were significant differences among the different combinations in the same differential expression type. According to the overall average, the specific expression types of hybrids accounted for 25.22%, and the dominant expression types of the parents accounted for 2146 %, 82.2% of silent expressions of parents, and 33.49% of silent expressions of single parents. (3) There was a significant positive correlation between silence expression of single parent and hybrid performance of plant height. There was a significant negative correlation between silence expression of parents and heterosis of spike. The dominant expression was negatively correlated with the heterosis of grain number per plant and grain weight per plant ; The rest of the expression types were not related to hybrid performance and heterosis of all agronomic traits, and the results were discussed