快中子辐照玉米自交系的细胞学效应及后代变异

Cytological effects and offspring variation of maize inbred lines irradiated by fast neutron

为了探索快中子辐照玉米的细胞学效应及后代变异,为玉米种质创新及品种改良提供有益的种质资源,本实验采用低剂量(0.36~4.19 Gy)的快中子辐照玉米自交系LY8405和PH6WC干种子。结果表明:两个自交系根尖细胞有丝分裂指数均随吸收剂量的增加而降低;核畸变率随吸收剂量的增加而升高;吸收剂量4.19Gy对自交系LY8405的M1染色体分裂行为影响效应最为明显,2.48 Gy对自交系PH6WC的M_1染色体分裂行为影响效应次之;辐照M_2、M_3代突变类型包括株型、叶色、穗形、株高、籽粒形状及大小等;生物学和细胞学效应表明,2.48~4.19 Gy的吸收剂量是0.36~4.19 Gy范围内快中子辐照选育玉米突变体的适宜剂量。

Dry seeds of maize inbred lines LY8405 and PH6WC were irradiated by fast neutron at doses of 0.36-4.19 Gy to explore the cytological effect of irradiation on maize for germplasm innovation and improvement. The results showed that with the increase of absorbed doses, the mitotic index of root tip cells decreased, while the rate of nuclear aberration increased. The chromosome division behavior of irradiated inbred lines LY8405 in Mx generation was the most obvious at dose of 4.19 Gy, followed by the irradiated inbred lines PH6WC at dose of 2.48 Gy. Abundant mutation types appeared in M2 and M3 generation of inbred lines LY8405 and PH6WC under fast neutron irradiation, including those of plant shape, leaf color, panicle length, plant height, grain shape, and grain size,etc. Biological and cytological studies show that with maize seed irradiated by fast neutron at 0.36-4.19 Gy, the appropriate dose range for breeding is 2.48-4.19 Gy.