Establishment Of Microspore Culture System For Pol TCMS And QTL Mapping Of Its Temperature-Sensitive Genes

The utilization of heterosis could significantly increase yield, solve the problem between yield and quality, and improve resistance/tolerance. It is one of the main achievements of modern agricultural science and technique. There are several efficient pathways to implement rapeseed heterosis such as cytoplasmic male sterility (CMS), genic male sterility (GMS), genic male sterility and cytoplasmic male sterility (GCMS), ecotypical male sterility (EMS), Chemical hybriding agents (CHA), Self incompatibility (SI), and so on. Polima cytoplasmic male sterility (Pol CMS) is currently the most important hybrid breeding system in China. However, that there are very few of Pol CMS maintainer lines stops from further utilization of Pol CMS in hybrid combinations with high heterosis.A new Pol CMS line, temperature-sensitive Polima cytoplasmic male sterility (Pol TCMS) had been selected in segregating progenies of Pol CMS line 'Xiangai A' × Restorer line (Yang et al. 1995, 1998). This novel Pol CMS line was partially fertile at low temperature before April, while sterile at high temperature after April, when it was sown in Wuhan in autumn. But it is stable sterile when it was planted in spring rapeseed growing area such as Kunming or Xining in summer. So they could be multiplied without using Pol CMS maintainer lines in the autumn-sowing area. In the spring-sowing area, they could be used to produce hybrid seeds as Pol CMS. Some experiments indicated that Pol TCMS has some preferable characters: 1) Hybrid-breeding program is simple. 2) It is easy to make hybrid combinations. 3) It could shorten breeding time. 4) The hybrids usually showed a significant increase in yield. For example, several hybrid cultivars, such as 'Huaza No. 10', 'Huaza No. 11', 'Huaza No. 12', 'Huaza No. 13' and 'Huaza No. 14' have been registered in China recently. So it indicated that Pol TCMS has great potential for application.Some experiments showed that the temperature sensitivity of Pol TCMS is controlled by several minor genes, and probably influenced also by genetic background (Yang et al.1997). In order to make the Pol TCMS system a wider application, it is necessary to initiate further study on them.In this research, the possibility of obtaining high-effective embryogenesis from Pol TCMS was studied by two semi-winter type Brassica napus L varieties ( 1815 and lun31 ), four Pol TCMS lines (8061A, 109A, 195Aand 206A) and F₁ from 109A× 571B.