影响小麦提型不育系种子质量的遗传因素

Genetic factors influencing seed quality of male sterile wheat lines with T. timopheevi cytoplasm

根据Ｔ型不育系和恢复系、不育系和保持系的两套双列杂交试验以及川７Ａ和其它保持系的４套回交试验，对影响Ｔ型不育系种子饱满度和发芽率的遗传因素进行了分析。发现不育系异交子粒的发育进程和充实程度主要取决于母体的基因型；而不育系种子的发芽率则受母体基因型和花粉供体基因型的共同影响。用川７Ｂ给其它不育系授粉得到的杂交种子，其发芽率明显地高于这些不育系与同型保持系杂交产生的种子；不育系种子的饱满度也因有了川７Ｂ的血缘而得到明显的提高，说明川７Ｂ中的核基因对Ｔ型胞质基因具有显性上位作用，利用这些核基因能够有效地改良Ｔ型不育系的种子质量。

Two sets of diallel crosses between male sterile lines (A-lines) with T. timopheevi cytoplasm and male fertility restorer lines (R-lines), and between A-lines and male sterility maintainer lines (B-lines), and 4 sets of back crosses between Chuan 7 A and other B-lines were carried out in 1998. These experiments were used for analyzing genetic factors influencing grain plumpness (GP) and seed germinating rate (SGR). It was found that genotype of female parents was the primary factor affecting grain plumpness of hybrid seeds developed on A-lines. But both male and female parents controlled seed germinating rate. The SGR of hybrid seeds developed on Alines was much higher when Chuan 7A was ed as pollen supplier than that of those seeds when their analogous B-lines was used as pollen supplier respectively. GP of A-lines w also increased with the invasion of Chuan 7A genome. This means that there is a epistatic dominance for some nucleus genes in Chuan 7A over the cytoplasm genes from T. timopheevi. The seed quality of wheat hybrids could be effectively improved by taking advantage these nucleus genes.