60Co-γ射线辐射对木薯组培苗的诱变效应

Mutagenic Effect on Tissue Culture Plants of Cassava Induced by 60Co-γ Irradiation

为探究60Co-γ射线辐射对不同木薯品种组培苗的诱变效应,以2个木薯品种新选048和SC205离体单芽茎段为试验材料,以不同60Co-γ射线辐射剂量(0、5、10、20、40 Gy)进行处理,观察比较不同辐射处理条件下组培苗的生长情况以及移栽后植株的生长状况。结果表明,随着60Co-γ辐射剂量的增加,2个品种组培苗的生根率和萌发率均显著降低;新选048和SC205的半致死剂量分别为15. 3 Gy和17. 2 Gy。随着辐射剂量的增加,对继代组培苗及其生根苗的生长伤害程度逐渐加强,株高、生根率、移栽成活率等指标均显著降低。不同品种对60Co-γ射线辐射的敏感程度存在差异,新选048的辐射敏感性更强。经60Co-γ射线辐射后,2个木薯品种组培苗均出现叶柄颜色变异、叶形变异、黄化苗、矮化苗等不同程度的形态变异。经大田移栽后统计,新选048变异率为3. 3%,SC205变异率为6. 6%。对突变材料进行SSR分子标记检测发现,其中有3条引物可检测SC205对照与突变体材料在分子水平上的差异;5条引物可检测新选048对照与突变体材料在分子水平上的差异。本研究结果为利用60Co-γ射线辐射诱变创造木薯新种质以及木薯诱变育种奠定了一定的理论基础。

To explore the mutagenic effects of 60Co-γirradiation,stem cutting of two cassava varieties,xinxuan 048 and SC205,were irradiated with 0,5,10,20 and 40 Gy of 60Co-γ,respectively.The growth of tissue culture seedlings with different radiation treatment and the growth of plants after transplanting were observed and compared.The results showed that the rooting rate and germination rate of two varieties were decreased significantly with the increment of the irradiation dose.The median lethal dose(LD50)for two varieties was defined as 15.3 Gy,17.2 Gy,respectively.With the increasement of the irradiation dose,the damage severity of tissue culture seedlings was reinforced,the seedling height,rooting rate and transplanting survival rate were decreased significantly.There were different vadiation sensitivity between varieties,xinxuan 048 are more radiation susception than SC205.After irradiation,different morphological variations such as petiole color,leaf shape,etiolated seedling and dwarf seeding were observed in both of two tissue culture seedlings.The variation rate of xinxuan048 and SC 205 was 4.4%and 6.6%,respectively.Three pairs of microsatellite(simple sequence repeat,SSR)primers were found to be polymorphism between genomic of SC205 wide type and mutants plants,five SSR primers were shown to be polymorphism between Xinxuan 048 wide type and it’s corresponding mutants.The results laid a foundation for creating a new cassava germplasms by 60 Co-gamma rays radiation and opening a new method for cassava breeding.