Abstract: 【Objective】 To clarify the effect of autumn irrigation in Yellow River Irrigation Districts on the seed germination of Orobanche cumana.【Methods】 The study had been carried out in Urad Front Banner of Inner Mongolia during 2014 to 2019.Sacks containing seeds of Orobanche cumana were put in the field and immersed in the irrigation water each November to next May,and the controlling sacks containing the same seeds were put in natural conditions and without irrigation.The seed samples were taken out at eah May,induced by GR24 and calculated their germination rates.【Results】 The germination rates of Orobanche cumana treated with autumn irrigation from 1 to 5 years were 46.62%,12.86%,0.79%,0,0,respectively,while germination rates of the control seeds were 71.95%,64.19%,64.88%,57.72%,69.88%,respectively.Autumn irrigation could significantly decrease the germination rates of Orobanche cumana seeds,the more years′ irrigation,the lower germination rates of the seeds.After 4 years irrigation,the germination rates was down to 0.【Conclusion】 The lower germination rates of Orobanche cumana was caused by autumn irrigation,it was mainly reason for why Orobanche cumana keeping a low infectin rate in the Yellow River Irrigation Districts of Bayannur.

Key words: Yellow River Irrigation Districts, Autumn irrigation, Orobanche cumana, Seed germination