Abstract:

The phenotype mutation of Hemarthria compressa induced by ⁶⁰Co-γ and the appropriate dosage of ⁶⁰Co-γ used for irradiation were studied using both forage type H. compressa ‘Ya'an’ andturf type H. compressa ‘H055’ in order to provide basic information for mutation breeding. Results showed that the survival rates of individual plants decreased with the increasing of irradiation dosage. The appropriate dosage of ⁶⁰Co-γ was 80~100 Gy for inducing H. compressa ‘Ya'an’ and 70~90 Gy for H. compressa‘H055’. The phenotypic variations of all tested materials were observed obviously and variation frequencies were 47.5% and 37.5%, respectively. The positive mutants of turf type H. compressa ‘H055’ with smaller leaves, more dwarf and slender stalks were obtained and accounted for 75% of all tested materials, while the positive mutants of forage type H. compressa ‘Ya'an’ accounted for 10%. These results indicate that radiation breeding method is more suitable for the turf type of H. compressa.

Key words: Hemarthria compressa, ⁶⁰Co-&gamma, irradiation, Critical dose, LD50, Phenotypic variation

摘要：

以牧草型‘雅安’扁穗牛鞭草（Hemarthria compressa‘Ya'an’）和草坪型‘H055’扁穗牛鞭草（H.compressa‘H055’）为材料，用⁶⁰Co-γ射线分别照射种茎，研究其形态变异及变异的适宜射线剂量，旨在为扁穗牛鞭草辐射诱变育种提供基本信息。结果表明：诱变材料的存活率随辐照剂量增加而降低，‘雅安’扁穗牛鞭草种茎适宜诱变剂量为80~100Gy，‘H055’扁穗牛鞭草种茎适宜诱变剂量为70~90Gy；辐射当代材料在植株形态性状上发生了较明显变异，其变异频率分别为47.5%和37.5%。并获得75%叶片变小、株高变矮、茎变细的草坪型‘H055’扁穗牛鞭草优异种质和10%植株变高的牧草型‘雅安’扁穗牛鞭草突变体，表明辐射育种方法更适合于草坪型扁穗牛鞭草的选育。

关键词: 扁穗牛鞭草, ⁶⁰Co-&gamma, 辐射诱变, 临界剂量, 半致死剂量, 表型变异