利用分子標誌建立玉米單倍體鑑定技術

Abstract

雙單倍體 (doubled haploid) 技術為玉米育種得以快速育成自交系的方法。由於單倍體誘導成功率僅約10%，能正確分辨單倍體的標誌為此技術的必要工具。本研究針對使用RWS衍生之單倍體誘導系與甜質玉米「好6」和「彩白18」雜交的組合，開發DNA分子標誌。這些DNA分子標誌也同時用來評估形態標誌R1 nj與 Purple1的單倍體鑑別正確率。ID1與ID4兩個InDel分子標誌用來篩檢2849株玉米幼苗。另外三個KASP分子標誌ZMKASP_002、ZMKASP_008及ZMKASP_009亦能分辨單倍體植株與單倍體誘導系正常授粉的雜交個體。基於2849株玉米幼苗的DNA分子標誌的基因型，R1 nj標誌鑑別單倍體植株的偽發現率 (false discovery rate) 為48%、偽陰性率 (false negative rate) 為25.7%。相較之下，雖然Purple1標誌的表現程度有時十分低，但Purple1標誌的基因型鑑別結果與DNA分子標誌的基因型100%吻合。

The doubled haploid technique is a method to develop inbred lines quickly in maize breeding programs. Because the haploid induction rate is only around 10%, efficient markers to identify haploid plant precisely are required. In the current study, DNA markers were developed for the combination of the RWS derived haploid inducer and the cross of G6 and C18 both of which are sweet corns. These DNA markers were also used to evaluate accuracy of two morphological markers R1-nj and Purple1. Two InDel markers ID1 and ID4 were used to screen a total of 2849 seedlings. Additional three KASP markers ZMKASP_002, ZMKASP_008, and ZMKASP_009 were also able to distinguish haploid individuals from hybrids of inducer lines. Based on the genotypes of 2849 seedlings, the R1-nj marker had 48% FDR(false discovery rate) and 25.7 % FNR(false negative rate). In contract, the genotypes of the Purple1 marker showed 100% matches to the genotypes of DNA markers while expressivity of the Purple1 marker were sometimes very low.