籼型多分蘖矮秆突变体的遗传分析及其相关生理特性

籼型多分蘖矮秆突变体“佳禾丛矮”(Jiahecongai,JHCA)是本研究室在进行成熟花粉辐照诱变育种过程中发现的.遗传分析表明,JHCA同时携带互不等位的半矮秆基因sd-1和另一个由核基因隐性突变造成的多分蘖矮秆基因,暂命名为xmd(t).从JHCA与野生型高秆品种“广场13”(GC13)的杂交后代中分离出只带xmd(t)且遗传稳定的单基因型突变品系“新佳丛”( Xinjiacong,XJC).为揭示xmd(t)突变所造成的多分蘖与茎秆矮化协同出现的机理,对XJC的相关生理特性进行了分析.全生育期去除分蘖芽的试验表明,突变体植株的矮化是由于或部分由于过多分蘖的发生所造成的,该突变体的实质是多分蘖突变体.显微分析和田间分蘖动态观察表明,突变体多分蘖特性的形成是由于分蘖芽发生更早、分糵级数多、分蘖节位更高,且分蘖持续时间更长所造成的.本研究也表明,多分蘖矮秆突变体是研究水稻分蘖分子机理的理想材料.

Genetic Analysis of High-tillering Dwarf Mutant in Indica Rice and Its Related Physiologic Characteristics

Rice is one of the most important crops in the world.Its plant architecture is an important agronomic trait that affects grain yield.Therefore,the elucidation in genetic and molecular mechanism that controls plant architecture in rice has an important theoretical value and practical significance.High-tillering dwarf indica rice mutant Jiahecongai(JHCA) was isolated from our mutation breeding irradiated by gamma(γ) ray.In our genetic studies,JHCA was found to carry two nonallelic recessive genes,semidwarf gene sd-1 and high-tillering dwarf gene xmd(t).Through the segregation analysis,we realized that the xmd(t) gene was actually responsible for its high tillering and partially its severely dwarfing in JHCA.A strain line possessing xmd(t) singly and having genetic stability was isolated from the hybrid offspring of JHCA and wild tall-culm variety GC13,and was named Xinjiacong(XJC).In order to explore the mechanisms of high tillering and dwarfism in XJC,its related physiological characters were analyzed.Removal of axillary buds proved that dwarfism of XJC was partly attributed to its excessive tillers,and the essence of this high-tillering dwarf mutant was hight tillering but not dwarfism.Analysis of micro-observation and the investigation of tillering dynamics in field showed that the formation of the high-tillering character in XJC was due to the following factors:the growth of tiller bud was earlier,the tiller nodes were higher and the duration time of tillering was longer.This research also suggested that high-tillering dwarf mutant was suitable for the molecular mechanism of tillering control in rice.