| Rapeseed is the fifth crop besides rice wheat maize and soybean in China, its cultivated area and total output both rank the first in the world, which play an important role in the agricultural economy. Rapeseed oil is the most important edible vegetable oil in China, which supplies 60% edible vegetable oil. It is well known that Rapeseed oil is one of the most healthful edible vegetable oil because of its high oleic acid content and low saturated fatty acid content. The present releasing varieties have two shortcomings in China, which are lower oleic acid content and higher saturated fatty acid content. Being lack of related germplasm, the advance of breeding for quality is slow. The utilization of modern biotechnology and traditional mutagenesis provides an important way to solve these problems, which can improve the germplasm and accelerate the process of breeding.New ways to improve Brassica napus CMS restore lines were studied in this paper, which included microspore culture, radiation mutagenesis and chemical mutagenesis. The materials used in this study were double-low Brassica napus CMS restore lines 1815,7812 and Lun-3l. The main results were as follows:1 Microspore culture and the fatty acid component analysis and disease resistance evaluating:1.1 The doubled haploid (DH) population derived from restore lines 7812 and 1815 by microspore culture were constructed, which included 68 and 57 lines respectively.1.2 In these two populations, the coefficients of variability of every fatty acid were not significant; 3 DH lines whose sums of oleic acid and inoleic acid were above 85% were found in the two populations respectively.1.3 The Sclerotinia disease resistance analysis evaluated in maturing stage by placing toothpicks, 7812 and 1815 were both highly susceptible, lesions spread very quickly, the average spreading of lesion was above 2cm/d during 3d-7d. Compared with CK, the disease resistances of some lines in 1815 were significantly improved.1.4 Few different bands were detected by AFLP analysis, which showed the genotypes of DH line in each population had little difference.1.5 This study suggested that microspore culture could make the genotype of the restore lines become homozygous quickly and maintain some of its perfect agronomic trait at the same time, and some improved lines on fatty acid and disease resistance could be scaned in the DH populations.2 The utilization of mutagenesis in germplasm enhancement2. 1 Among the petiole, stem and root isolated from haploid plantlet, the callus derived from the stem growed well on MS medium containing 0.5 mg/L 2,4-D and 2 mg/L 6-BA. The most suitable dose of y rays for callus was 0.774 C/Kg -1.032 C/Kg. The AFLP analysis showed that the genetic background of 39 regenerations was similar; because there were only 8 primer pairs detected 43 different bands in 9 regenerations.2. 2 The five different lines of Lun31 were treated with 25.8 C/Kg Co60- y rays, the results indicated that Gu2-3 was sensitive to y rays and Gu2-\ was tolerant. The radiation treatment had little effect on the germinating ratio of the tested varieties. Analysis of M, seeds fatty acid component in Gu2-1 and Gw2-2 suggested that the effect of radiation mutagenesis on erucic acid content was significant, while the effects on oleic acid content, inoleic acid content and inolenic acid content were little.2. 3 The most suitable concentration of EMS was 0.1% -0.2% and the most efficient time needed to treat the embryoes with 0.1% EMS was 90 min -120min. It was efficient and economical to treat haploid with aqueous solution containing 100mg/L colchicines and 2% sugar for 5 days to obtain diploid. Effects of EMS on oleic acid content and inoleic acid content were significant, high oleic acid content (68.62%) germplasm was obtained in this study.2.4 According to the above three mutagenesis methods, although the mutagenesis with seeds is easy, but the workload of screening is huge; the mutagenesis with in vitro haploid callus can enhance the mutation frequency and obt... |
PDF Full Text Request