Evaluation Of Genetic Variation In Brassica Napus Progeny Derived From Different Mutation Ways

Rapeseed is the fifth largest crop, just after rice, wheat, maize and soybean in China. It plays an important role in the agricultural economy. As proved for many years, conventional breeding technologies have been contributing to elite variety that satisfy the requirements in agricultural production, and improve yield and increase farmer's income. But those breeding technologies have shortcomings, such as long cycle and trivial operation, so it is necessary to explore a new breeding technology with short cycle and good effect. The utilization of tissue culture and mutagenesis provides an important way to solve these problems, which could improve the germplasm and accelerate breeding process.In order to explore regeneration mutagenesis and estimate variation of the progenies, new ways were applied, which include microspore culture, physical and chemical mutagenesis, identification resistance of Sclerotinia sclerotiorum, AFLP technology and NIRs analysis, and so on. The materials used in this study were Brassica napus CMS restore lines 5148DH and TCMS lines 195-14A. The main results were as follows:1. The results of dealing with haploid callus of 195-14A byγrays and UV indicated that the LD50 was 4000R.2. The AFLP analysis of 77 regenerations showed that there were only 27 polymorphic plants, accounting for 7.0% in population. The resemble coefficient among regenerations is from 0.98 to 1.0, and the population is divided to two groups at 0.98.3. As the increasing of radiation time, the doubling rate of regeneration increased.4. The induced rate of callus in 5148DH is higher than that in 195-14A. And the induced rate of callus derived from hypocotyl is higher than that from cotyledon. The induced rate of callus on MS₃ medium is higher than that on other MS medium.5. The LD50 ofγrays in two materials is 3000R and 4000R respectively. The LD50 of EMS in 195-14A is 2.0%. The results ofγrays and EMS experiment indicated that 195-14A was sensitive to mutation.6. The AFLP analysis of two mutation populations showed that there were 11 and 53 polymorphic regenerations, accounting for 34.4% and 100% in each population.7. The NIRs analysis of M₂ inbred seed derived from callus showed that mutagenesis could reduce could reduce glucosinolate content,oleic content and oleic acid content, especially the variance of glucosinolate content is maximal. We only find two plants with low Glucosinolate content, respectively 0.62 and 7.95umol/g. 8. According to two identification resistance methods at seedling and maturing stage, we find five plants with better resistance.9. The mutation decreases the germinating ratio to different extents, but the lethal effect of EMS is stronger than that ofγrays.10. According to screening and identification morphologically in four M₂ populations, we find some mutants with petals color, sterile character, wrinkled caulis, purple caulis, lack chlorophyllous content, waxyless, podgy anglepod and highness.11. The AFLP analysis of four M₂ populations showed that there were 30, 32, 35 and 46 polymorphism regenerations respectively, accounting for 31.6%, 33.7%, 36.8% and 48.9% in each population. We could also conclude that EMS treatment in 195-14A has the most effective mutagenic effect.12. According to two identification resistance methods at seedling and maturing stage, we discover twenty plants with better resistance in four populations.13. The NIRs analysis of four M₃ inbred seed populations showed that mutagenesis could reduce glucosinolate content,oleic content and oleic acid content, especially the variance of glucosinolate content is maximal, and it's easier to arose variance of glucosinolate content byγrays than by EMS. In four populations we only find 31 plants with low glucosinolate content that means less than 10umol/g.