研究了不同类型的水稻品种空间搭载和地面60Co γ辐照两种条件下的诱变敏感性和诱变效应。结果表明，诱变的敏感性均以粳稻强于籼稻，推广种强于农家种，籼稻中以中籼和晚籼>早籼，而不同粳稻气候生态型间的差异较小。对γ辐照不敏感的品种大多数对空间诱变也不敏感，而对γ辐照敏感的品种中仅有1/4对空间诱变敏感。空间搭载对54.2%的品种的处理当代秧苗生长具有加速作用，有的同时提高结实率。M2代研究表明，两种诱变处理均能诱发株高和抽穗期突变，但其突变频率差异较大。空间搭载处理的M2代矮秆、高秆和早熟的突变频率与M1代总生理损伤存在显著正相关。表明空间环境与地面γ辐照的诱变机制可能不完全相同。本研究结果对开展水稻空间诱变育种具有一定的指导意义。
Radiosensitivity，which is defined as visible damage or stimulus to seedling growth by physical or chemical mutation treatments, is a very important characteristic in the field of induced mutation breeding. In the present study, the radiosensitivity and mutagenic effects were studied using 24 different rice cultivars by treatments of space carrying of spacecraft “Shen-Zhou 4” which was launched in 2002 in China and 60Co γ-irradiation on the ground. Radiosensitivity was expressed based on the total physiological damage or stimulus of seedling height and seed setting rate in M1 generation, and mutations of plant height and heading date in M2 were observed. The results indicated that japonica rice had stronger radiosensitivity of space environment mutation and γ-irradiation than indica rice, bred cultivars stronger than landraces, medium-late indica and late indica stronger than early indica whereas no significant differences among different japonica climate ecotypes. Most cultivars non-sensitive to γ-irradiation were also non-sensitive to space mutation and only one-fourth of cultivars sensitive to γ-irradiation showed radiosensitivity to space mutation (Table 1). Space flight had obvious stimulus effects on seedling growth for 54.2% cultivars. In M2 generation, mutations of plant height and heading date could be induced by both space environment and γ-irradiation but the mutation frequencies were quite different (Table 2). There were significant correlations between the total physiological damage in M1 and the mutation frequencies of dwarfing, high plant and early maturity in M2 after space flight. A conclusion is that space environment shares incomplete same mutagenic mechanisms with γ-irradiation. The results in the present study provide some useful information for rice space mutation breeding in the future.
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