Abstract: 【Objective】To study effects of different selenium application amount on selenium content,quality and yield of flower buds of Hemerocallis citrina Baroni,provide reference for planting selenium-rich Hemerocallis citrina Baroni.【Methods】Four varieties of Hemerocallis citrina Baroni were selected,including Changzuizihua,Sanyuehua,Qingchong,and Dawuzui. Selenium fertilizer was applied to the roots during the bolting period,with selenium application amounts of 150 kg/hm² （Se10）,225 kg/hm²（Se15）,and 300 kg/hm²（Se20）,respectively,with no selenium fertilizer application as the control （Se0）. The selenium content,quality,yield,and selenium accumulation in the flower buds of Hemerocallis citrina Baroni were measured after harvesting on June 30 and July 8,2022.【Results】After selenium treatment,the selenium content and selenium accumulation of Hemerocallis citrina Baroni flower buds increased,and the selenium content and selenium accumulation of Changzuizihua were the highest,which were 0.031 mg/kg and 752.786 mg/hm². With the increase of selenium application amount,the selenium content in the flower buds of all varieties at two picking times showed a trend of first increasing and then decreasing,the optimal selenium application amount for Changzuizihua and Sanyuehua was 150 kg/hm²,and the selenium content in flower buds was 0.031,0.070 mg/kg and 0.010,0.003 mg/kg,respectively. While the optimal selenium application amount for Qingchong and Dawuzui was 225 kg/hm²,and the selenium content of flower buds was 0.006,0.015 mg/kg and 0.015,0.030 mg/kg,respectively. After drying,the selenium content of dry sample showed a multifold relationship with that of fresh sample,which was 3.47-4.00,consistent with the water content. There was no loss of selenium content during drying process. With the increase of selenium application amount,the flower bud weight and flower bud yield of all varieties increased first and then decreased,but the effects on bud length and width were different among all varieties. 【Conclusion】Moderate application of selenium fertilizer can improve the selenium content,quality,and yield of Hemerocallis citrina Baroni flower buds. Excessive application of selenium fertilizer can inhibit the weight of Hemerocallis citrina Baroni flower buds and reduce yield.

Key words: Selenium fertilizer, Hemerocallis citrina Baroni, Flower bud, Selenium content, Quality, Yield