利用远缘杂交和未减数配子基因创制小麦加倍单倍体

Creation of doubled haploid in wheat using distant hybridization and unreduced gamete genes

未减数配子的结合实现染色体自动加倍,是多倍体物种起源的重要途径,也是提高作物单倍体育种效率的重要手段。我们前期从四倍体小麦发掘出控制未减数配子形成的强效QTL位点QTug.sau-3B,并通过人工合成小麦为“桥梁”,将其导入到综合农艺性状优良的小麦新品系中。本实验使用5份含未减数配子基因的优良小麦新品系与不含未减数配子基因的小麦推广品种的F1杂种作母本与3份白茅(Imperata cylindrica)进行远缘杂交,共授粉4610朵小花,结实1965粒,经幼胚拯救获得244个幼胚,其中50个幼胚发育正常生长为50个小麦单倍体植株。由于小麦单倍体植株未减数配子基因的表达易受环境影响,因此,对单倍体植株在相同光周期(18 h光照/6 h黑暗)下进行了不同温度25℃/18℃、25℃/15℃和25℃/10℃处理,结果表明,25℃/18℃和25℃/10℃条件下编号为H31单倍体植株能够结实,自交结实率分别为4.35%和2.41%。该研究结果为建立“基于小麦-白茅杂交实现染色体消除和未减数配子基因实现染色体自动加倍”的小麦单倍体育种技术提供了参考。

The union of unreduced female and male gametes leads to spontaneous chromosome doubling,which is not only an important way of the origin of polyploid species but also an essential tool for enhancing crop doubled haploid breeding efficiency.A major quantitative trait locus QTug.sau-3B responsible for unreduced gametes formation was discovered in tetraploid Triticum turgidum wheat and was further transferred to elite common wheat lines using synthetic hexaploid wheat as a bridge.This objective of this study is to make wheat/wheat F1 hybrids between the elite lines with this gene region and commercial cultivars and to evaluate the efficiency of QTug.sau-3B gene leading to spontaneous chromosome doubling.Wheat/wheat F1 hybrids and their parents were pollinated with the fresh pollen of Imperata cylindrica to produce wheat haploid through chromosome elimination of I.cylindrica.Doubled haploid(DH)were then developed by spontaneous chromosome doubling in haploids because of the union of unreduced female and male gametes.In this experiment,5 F1 hybrid materials and 3 I.cylindrica materials were used for distant hybridization.4610 florets were pollinated,1965 seeds were produced,244 embryos were obtained,and 50 wheat haploid plants were obtained.In different temperature treatments,the haploid plant numbered H31 set seeds at 25℃/18℃(18 h/6 h)and 25℃/10℃(18 h/6 h),and the self-fertilization rate was 4.35%and 2.41%,respectively.The results of this study provide a reference for the establishment of wheat haploid breeding technology of chromosome elimination based on wheat-I.cylindrica hybridization and automatic chromosome doubling based on unreduced gamete genes.