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Le_2~(dav)基因与Le_1位点的Le_1基因或Le_2位点的Le_2基因结合时,棉花胚珠具有杂种致死效应,从出苗到苗后21天,逐渐产生枯斑甚至死亡。枯死时间可能受等位基因Le_1、Le_2的剂量效应及其与Le_2~(dav)基因的互作控制,但目前尚未阐明它们之间的真实遗传关系.本研究目的在于测定:(Ⅰ)枯死是否是由Le_1和Le_2位点遗传控制的;(Ⅱ)不同基因型杂交时,基因作用的时间和方式是否一致。用五个栽培品种(Le_1Le_1Le_2Le_2)作为Le_1、Le_2基因的供体,分别与le_1le_1le_2le_2植株杂交,其F_1代(品种×le_1le_1le_2le_2)再分别与le_1le_1Le_2~(dav)Le_2~(dav)植株正反交,调查其杂交后代致死反应出现的时间和表现。按幼苗死亡的时间作出频率图,分析得表型频率与期望分离频率相反。表明。Le_2~(dav)致死系统中,Le_1、Le_2基因的剂量增加能促进枯死,且品种间的变异表明:Le_1—Le_2~(dav)、Le_2—Le_2~(dav)间的互作是不同的。造成这种差异的原因可能是:(Ⅰ)其它基因的作用;(Ⅱ)不同基因型背景对等位基因作用的修饰效应;(Ⅲ)Le_1和Le_2位点具有多型性。
When Le_2 ~ (dav) gene was combined with Le_1 gene of Le_1 or Le_2 gene of Le_2, cotton ovule had a hybrid lethal effect. Gradual emergence and death of cotton ovule occurred from 21 days after emergence to 21 days after emergence. The dead time may be controlled by the dose effects of alleles Le_1 and Le_2 and its interaction with Le_2 ~ (dav) genes, but the true genetic relationship between them is not yet elucidated.The purpose of this study was to determine whether: (Ⅰ) Is genetically controlled by Le_1 and Le_2 loci; (Ⅱ) whether the timing and manner of gene interaction are the same for different genotypes. Five cultivars (Le_1Le_1Le_2Le_2) were used as donor of Le_1 and Le_2 gene and crossed with le_1le_1le_2le_2 respectively. The F_1 generation (cultivars × le_1le_1le_2le_2) were crossed with le_1le_1Le_2 ~ (dav) Le_2 ~ dav, The timing and performance of the lethal reaction of their offspring. According to the frequency of death of seedlings time chart, the analysis of phenotypic frequency and the expected frequency of separation contrary. show. In Le_2 ~ (dav) lethal system, the increase of Le_1 and Le_2 gene dose could promote the death, and the variation among cultivars showed that the interaction between Le_1 ~ Le_2 ~ (dav) and Le_2 ~ Le_2 ~ (dav) was different. The reasons for this difference may be: (I) the role of other genes; (II) the effect of different genotypes on allele modification; and (III) polymorphisms in Le_1 and Le_2 loci.