种子含水量与辐射剂量对寒地粳稻出苗率的影响

Effects of Seed Moisture Content and Irradiation Doses on Seedling Emergence of Japonica Rice in Cold Region

摘要:

辐射诱变是创制水稻种质资源和选育新品种的有效途径，而种子含水量和辐射剂量是影响辐射耐受性的重要因素。为顺利开展寒地水稻突变体库构建和辐射诱变育种工作，对不同含水量寒地粳稻种子的适宜辐射剂量进行探索。本研究以黑龙江省不同积温带的4个主栽粳稻品种为试验材料，采用不同剂量（0、250、280、300、330、350 Gy）⁶⁰Co-γ射线辐射不同含水量粳稻种子，处理后统计种子出苗率，分别进行含水量与品种、含水量与辐射剂量两因素方差分析。结果表明，在“含水量×品种”模型中，对出苗率的影响效应依次为：含水量主效应>品种主效应>含水量与品种的交互效应；在“含水量×辐射剂量”模型中，影响效应依次为：含水量主效应>辐射剂量主效应>含水量与辐射剂量的交互效应，以上结果说明含水量是影响粳稻种子辐射耐受性的关键因素。在辐射剂量不高于350 Gy条件下，随着含水量的提高，种子的辐射耐受性增强，而随着辐射剂量的提高，种子的辐射耐受性降低。当含水量高于14%时，种子的辐射耐受性显著增强。当种子含水量在14%～16%时，品种的辐射耐受性表现为：龙粳46>龙粳31>绥粳18>松粳28，龙粳46种子的辐射耐受性显著高于松粳28，龙粳31与绥粳18种子的辐射耐受性无显著差异。对于4个粳稻品种而言，当种子含水量接近14%时，辐射剂量250、280 Gy是半致死剂量，种子出苗率接近50%；当种子含水量在14%～16%时，辐射剂量350 Gy是半致死剂量，种子出苗率为50%左右。

Abstract:

Irradiation-induced mutation is an effective way to create rice germplasm resources and breed new varieties. Seed moisture content and irradiation dose are important factors affecting irradiation tolerance. To smoothly carry out the construction of japonica rice mutant libraries and irradiation mutagenesis breeding in cold regions,this study explored the suitable irradiation doses for japonica rice seeds with different moisture contents. Using ⁶⁰ Co-γ rays, seeds of four main japonica rice varieties(collected from different accumulated temperature zones in Heilongjiang Province) with different moisture contents were irradiated at six doses(0, 250, 280, 300, 330, 350 Gy). After treatment, the seedling emergence rate was recorded, and two-factor analysis of variance(ANOVA)was conducted for the combinations of "moisture content × variety" and "moisture content × irradiation dose".The analysis results showed that in the "moisture content × variety" model, the factors influencing seedling emergence ranked as follows: main effect of moisture content > main effect of variety > interaction effect between moisture content and variety. In the "moisture content × irradiation dose" model, the influencing factors ranked as: main effect of moisture content > main effect of irradiation dose > interaction effect between moisture content and irradiation dose. These results indicate that moisture content is the key factor affecting the irradiation tolerance of japonica rice seeds. When the irradiation dose was not higher than 350 Gy, the irradiation tolerance of seeds increased with the increase of moisture content but decreased with the increase of irradiation dose. When the seed moisture content was higher than 14%, the irradiation tolerance of seeds was significantly enhanced.When the seed moisture content was between 14% and 16%, the irradiation tolerance of the four varieties followed the order: Longgeng 46 > Longgeng 31 > Suigeng 18 > Songgeng 28. Specifically, the irradiation tolerance of Longgeng 46 seeds was significantly higher than that of Songgeng 28, while there was no significant difference in irradiation tolerance between Longgeng 31 and Suigeng 18. For the four varieties, when the seed moisture content was close to 14%, the median lethal irradiation doses were 250 and 280 Gy(with seedling emergence rate close to 50%). When the seed moisture content ranged from 14% to 16%, the median lethal irradiation dose was350 Gy(with seedling emergence rate around 50%).