Abstract: To efficiently create new cold-tolerant germplasm of hybrid Pennisetum （Pennisetum glaucum×P. purpureum）， this study used seeds of ‘Bangde No.1’ as material and employed the combined mutagenesis of Atmospheric Room Temperature Plasma （ARTP） with different durations （0，20，30，40 min） and different concentrations （0%， 0.4%， 0.8%） of Ethyl Methanesulfonate （EMS） to screen the cold-tolerant mutants. The results showed that both 0.4% and 0.8% EMS treatments significantly reduced seed germination. The germination rate under the 0.4% EMS treatment decreased approximately 50% of that of the control， whereas no seedlings were obtained following the 0.8% EMS treatment. In addition， the 0.4% EMS treatment significantly reduced plant height， leaf length， leaf width， stem diameter， and tiller number， indicating that EMS markedly inhibited seed germination and seedling growth of hybrid Pennisetum. Under the combined mutagenesis treatments， the combination of 0.4% EMS with 30 or 40 min ARTP significantly increased the germination rate， compared with the 0.4% EMS treatment. Moreover， the combination of 0.4% EMS and 30 min ARTP produced a higher proportion of seedlings with promoted growth-related traits， suggesting that an appropriate dose of ARTP could partially alleviate the inhibitory effects of EMS on seed germination and seedling growth. Following multiple rounds of screening， including low-temperature stress at the seedling stage， comprehensive physiological evaluation， natural cold stress under the field condition， and overwintering evaluation at a high-altitude area， three cold-tolerant mutants were obtained， including one from the 20 min ARTP treatment and two from the 30 min ARTP+0.4% EMS treatment. The optimal mutagenesis protocol was identified as seed soaking for 1 h followed by 30 min ARTP treatment and 0.4% EMS treatment for 8 h， obtaining 1% cold-tolerant mutant. This study provides an effective strategy for the increase of cold-tolerant germplasm and the genetic improvement of hybrid Pennisetum.

Key words: Hybrid Pennisetum, ARTP-EMS combined mutagenesis, Cold tolerance, Germplasm innovation

摘要： 为高效创制杂交狼尾草（Pennisetum glaucum×P. purpureum）耐寒新种质，本研究以‘邦得1号’种子为材料，采用不同时间（0，20，30，40 min）常压室温等离子体（Atmospheric room temperature plasma，ARTP）不同浓度（0%，0.4%，0.8%）甲基磺酸乙酯（Ethyl methanesulfonate，EMS）进行复合诱变，筛选耐寒突变体。结果表明：0.4%，0.8% EMS处理均显著降低种子发芽率，其中0.4% EMS处理发芽率降至约为对照的50%；0.8% EMS处理未获得诱变实生苗，0.4% EMS处理株高、叶长、叶宽、茎粗、分蘖均显著低于对照；说明EMS显著抑制杂交狼尾草种子发芽及幼苗生长。在复合诱变中，0.4% EMS与30或40 min ARTP复合处理发芽率显著提高，其中0.4% EMS与30 min ARTP复合处理对实生苗生长表型正向促进的比例较高，说明适宜剂量ARTP可能缓解EMS对其发芽和幼苗生长抑制作用。通过对诱变后代进行苗期低温胁迫、生理指标综合评价、大田自然冷胁迫及高海拔越冬试验等多重筛选，共获得3株耐寒性显著增强的突变体，1株来自20 min ARTP处理，2株0.4% EMS复合30 min ARTP处理。本研究发现浸种1 h+30 min ARTP+0.4% EMS处理8 h为最佳诱变体系，耐寒突变体诱变效率为1.0%；可为杂交狼尾草耐寒种质创新及育种应用提供支撑的具体落脚点。

关键词: 杂交狼尾草, ARTP-EMS复合诱变, 耐寒性, 种质创新