小麦显性矮秆基因复等位多态特性研究

 世界小麦矮化育种主要使用隐性矮源。在普通小麦中发现的显性矮源均因导致植株极度矮化（20~55　cm）而未能在小麦育种中广泛应用。笔者发现,将显性矮源矮变1号（4DS携带Rht10,25~30 cm）及矮苏3（4BS携带Rht3,55 cm）的原种大群体种植或施以诱变因子并将其与中、高秆的小麦品种杂交、回交,从其分离世代的大群体中,均可选择到一些株高呈不同程度提升的稳定的突变株系。采用近等基因系法对不同株高突变衍生系的研究表明：其提升的株高真实遗传,各自均携带一个不同株高的半显性矮秆基因,随突变衍生系株高的提升,近等基因系的产量性状显著优化。采用标志基因测交法以及生理生化遗传标记对突变衍生系携带的不同株高的半显性矮秆基因重新进行了基因定位,确认它们分别与Rht10及Rht3的座位相同,因而均是其突变衍生的复等位基因。提出显性矮秆基因具有"复等位多态特性",即极度矮化的显性矮秆基因容易突变为一群株高提高程度不同的、可以达到小麦育种理想株高的半显性矮秆复等位基因。

Studies of Multiple-Allelic Polymorphism of Dominant Dwarfing Genes in Wheat

Dwarfing breeding of wheat in the world is confined to the exploitation of recessive dwarfing sources. None of the dominant dwarfing sources discovered in common wheat (Triticum aestivum L.) has found wide exploitation in wheat breeding due to the extreme dwarfness of their plants (20-55 cm). It was found that some stable mutant lines with plant height enhanced to different extents could be obtained in large populations derived from the stock seeds of the dominant dwarfing sources Aibian 1 carrying Rht10 on 4DS and being 20-55 cm in height and Aisu 3 carrying Rht3 on 4BS and being 55 cm in height, or from their descendants of induced mutation treatments, or from the segregating descendants of their crosses with mid- or tall-statured genotypes. Subsequently, these mutation-derived lines differing in plant height with near isogenic lines were studied and it was observed that the character of their enhanced plant breeds true, each carries a semi-dominant dwarfing gene for a definite height and that as the plant height of the mutation-derived lines rises, the yield-contributing characters of their near isogenic lines are significantly improved. When test crosses with marker genes and physiological and biochemical genetic marker tests were performed to re-localize the semi-dominant dwarfing genes carried by the mutation-derived lines, it was confirmed that they share common loci with Rht10 and Rht3 and that they are all mutation-derived multiple alleles. It is thus speculated that dominant dwarfing genes are of multiple-allelic polymorphism, in other words, dominant dwarfing genes, which are ultra-dwarfing, are liable to develop by mutation into a group of multiple alleles with plant height enhanced to different extents and some may have a height close to the ideal plant height for wheat breeding.