利用粘果山羊草细胞质1B/1R易位系诱导小麦单倍体频率的研究

STUDIES ON THE FREQUENCY OF HAPLOID WHEAT INDUCED BY. Ae.kotschyi CYTOPLASM 1B/1R TRANSLOCATION LINES

用具有粘果山羊草(Ae. kotschyi)细胞质的1B/1R易位系转育成的K型小麦雄性不育系为基本材料,通过随体数目和C—显带技术鉴定了不育系、恢复系及其亲本的染色体组成,以中国春重双端体2t″1B和缺—四体1B°1D~Ⅳ与其杂交,观察了F_1减数分裂中期Ⅰ的染色体构型和C—显带特征。调查了有代表性的10个k型不育系及其中三个不育系与中国春重双端体2t″1B或缺—四体1B°1D~Ⅳ杂交F_1的单倍体诱导频率。结果表明,多数k型1B/1R不育系均可产生较高频率的单倍体,但不育系间差异很大,个别k型1B/1R不育系不产生单倍体,说明单倍体的产生除受1R短臂上的诱导单倍体基因作用外,还受其他基因的影响,同时也受父本基因型和染色体结构的影响,试验证明,1B染色体缺失或端体等非整倍体作为父本可以大大提高诱导单倍体的频率(接近70%),这种方法诱导产生的是单倍体种子,一般发芽正常,发育良好,在异质小麦育种方面具有重要实践意义。但由于这种单倍体均为孤雌生殖所致,应用受到一定限制,因此本文提出了如何应用的参考方案。

A series of male-sterile lines, their parents and restoration lineswith Ae. kotschyi cytoplasm were used for the investigation of haploid induced by the alien cytoplasm in wheat. The numbers of satellites were recorded and C-banding technique was used for confirming B or 1B/1R chromosome in genomes of the materials. Three K-type ms lines and R-lines Shaannong No.17 were crossed with CS double ditelosomic 2t″1B or nulli-tetrasomic 1B°1D~Ⅳ to observe chromosomal pairing configurations and the frequency of haploid induced in F_1. The results showed that the frequency of haploid induced ranged from 0% to 34.4% in ten male-sterile lines with Ae. kotschyi cytoplasm indicating that the frequency of haploid not only depended upon the interaction between Ae. kotschyf cytoplasm and the parthenogenesis gene on short arm of 1R chromosome but also was affected by the genotype. The frequencies of haploids in F_1 from the K-type ms lines crossing with CS double ditelosomic 2t″1B or nullitetrasomic 1B°1D~Ⅳ were much higher than that of in K-ms lines. Using this crossing method the frequency of haploid can be increased as high as 69.2%. It suggested that the frequency of haploid was even related to the genomes or the aneuploid with male parents. Because of the parthenogenesis the use of haploid induced by the alien cytoplasm for alloplasmic wheat breeding was limited so that a breeding scheme was proposed.