对一个玉米双重标记新突变基因(os)的染色体定位和初步遗传研究

The Chromosomal Location and Inheritance of a New Corn Kernel Mutant Gene (os) With Pleiotropic Effects

利用一套16个玉米B-A染色体易位的系列材料,和一套11个由wx基因标记易位断点的第9染色体相互易位材料,测定了一个新发现的玉米隐性突变基因os(opaque-small germ)所属的染色体。两个结果相互印证,证明该基因位于第2染色体短臂。os基因具有产生不透明胚乳和小胚面的双重遗传效应,是一个良好的遗传标记。这一特性有可能用来检查异雄核受精或定向受精的存在和比数。os基因除缩小种胚体积之外,也显著地降低胚中的含油量以及整个子粒的含油量,所以可视为控制玉米子粒含油量的一个主效基因。在高油遗传背景下和低油遗传背景下,os基因引起含油量降低的比数大致相当,表明该基因与控制玉米油分含量的多基因系统之间存在着某种相互重叠的互作效应,但os基因对玉米油分的主要脂肪酸组成无太大影响。

A natural corn kernel mutant with opaque endosperm and small germ size was confirmed to be controlled by a single recessive os gene. A set of 16 B-A chromosome translocations and a set of 11 wx-marked chromosome 9 translocations were used in testing the chromosome location of this gene. The results indicated that this gene was located on the short arm of chromosome two. Because the unique pleiotropic effects, os gene could be used as a double genetic markers, especially in monitoring the existence and ratio of heterofertilization and directed fertilization.In addition to the reduced germ size, os gene also caused dramatic decrease of oil content in the germ as well asin the whole kernel, so it can be regarded as a major gene controlling corn oil content.The reduced ratio of oil content caused by os gene was quite similar under both high and low oil inbred background, indicating that the os gene and the po-lygenic oil controlling system had an overlapped genetic interaction. However, the major fatty acid composition of corn oil was not significantly influenced.