Abstract:

In order to understand the difference in the response of wild and cultivated lotus seeds to the gamma rays,⁶⁰Co-γ radiation with various doses were used to treat the seeds of Nelumbo nucifera Weishan Hong and 50 cultivars. It was found that the numbers of spread leaves and roots, survival rate of the seedlings dropped sharply when the seeds were treated at 320 Gy for wild Weishan Hong, the treatment of higher doses at 750 and 1 000 Gy severely inhibited unfolding of the young leaves, and the survival rates of the seedlings were 0.6% and 0, respectively. By analysis with the linear regression, the semi-lethal dose of ⁶⁰Co-γ for the seeds of wild lotus Weishan Hong and cultivated locus was 192 and 173 Gy, respectively, indicating the higher tolerance of the Weishan Hong seeds to ⁶⁰Co-γ radiation. From 1 150 irradiated seeds of Weishan Hong, a mutant with narrow tepals was obtained, then a new cultivar chenshan Feiyan was bred. For this cultivar, the mean width/length of the tepals was 0.31, which was significantly lower than 0.44 of the wild type Weishan Hong. Also, the tepal number per flower, flower density and emerging leaf density were significantly reduced. Based on this study, the suggested irradiation dose of seeds from wild and cultivated lotus could be 150 - 200 Gy and 130 - 180 Gy, respectively, for future radiation breeding and mutant induction. This research gives technical references to create new germplasms by large-scale radiation of seeds with γ rays in lotus industry, and also provides a good parent for producing novel cultivars with specific tepal-shapes.

Key words: lotus, irradiation breeding, lotus seed, semi-lethal dose, wild lotus, γ radiation

摘要：

为了解γ射线对荷花(Nelumbo Adans.)野生型和栽培品种莲子的辐射效应及其差异,本研究利用不同剂量⁶⁰Co-γ射线对野生型荷花微山红(N. nucifera Weishan Hong)和50个栽培品种的莲子进行辐射处理。结果表明,微山红莲子的钱叶展开数量、生根效果和存活率在320 Gy处理下急剧下降,750和1 000 Gy处理严重抑制了莲子的钱叶发育,幼苗存活率分别为0.6%和0。利用线性回归方程,计算微山红野生型莲子和其他品种莲子的半致死剂量分别为192和173 Gy,即两者对⁶⁰Co-γ射线的耐受性存在19 Gy剂量差异。基于1 150粒微山红莲子的辐射处理,筛选得到1株花被片狭长的变异个体,以此培育为新品种辰山飞燕。该品种花被片宽长比均值为0.31,显著小于野生型(0.44),且其花被片数量、花密度及立叶密度也显著降低。后续荷花辐射育种及突变体筛选时,野生型和栽培品种莲子的辐射剂量范围建议分别参考150~200 Gy和130~180 Gy。本研究为荷花产业中利用γ射线大规模辐射莲子创制新种质提供了技术参考,也为荷花瓣形育种提供了良好亲本。

关键词: 荷花, 辐射育种, 莲子, 半致死剂量, 野生莲, γ射线