Abstract: To explore the effects of ethephon ripening acceleration on yield and quality of different rapeseed (Brassica napus L.) cultivars, three rapeseed varieties/lines (Shuangyou 195, PW-1B and 19FW-1) were used as experimental materials. Four ethephon concentrations (500, 750, 1 000 and 2 000 mg/kg) and three spraying dates (17 May, 20 May and 22 May) were arranged for the ripening-accelerating trial. After harvest, the moisture contents of pod husks, seeds and straws, as well as yield and quality traits of plants were determined. The results showed that except for a few treatments, the moisture contents of pod husks, straws and seeds of three rapeseed varieties/lines were markedly lower than those of the control. In terms of germination rate, all treated Shuangyou 195 samples maintained a germination rate above 90%. No significant differences in germination rate of 19FW-1 were detected between ethephon treatments and the control, whereas low-concentration ethephon applied at the early stage significantly impaired the germination rate of PW-1B. The grain yield of all tested varieties/lines declined to varying extents, with cultivar-specific discrepancies among genotypes. Quality analysis showed that after ethephon spraying for Shuangyou 195, the contents of high oleic acid, oleic acid, linolenic acid, palmitic acid and stearic acid decreased, while the contents of linoleic acid and protein increased. For PW-1B, the contents of glucosinolate, high oleic acid, linolenic acid, palmitic acid and stearic acid were reduced, whereas linoleic acid and protein contents were elevated. For 19FW-1, the contents of glucosinolate, high oleic acid, oleic acid, linolenic acid, protein, palmitic acid and stearic acid decreased, and only the linoleic acid content increased. Considering the comprehensive performance of yield and quality, ethephon could be practically applied for ripening acceleration in rapeseed production. For the cultivar Shuangyou 195, 2 000 mg/kg ethephon was recommended to be sprayed at 7-8 days before harvest with appropriately advanced harvesting time. For the colored rapeseed lines PW-1B and 19FW-1, spraying concentrations of 2 000 mg/kg and 1 000 mg/kg ethephon at 5-6 days before harvest were the optimal treatments, respectively.

Key words: rape (Brassica napus L.), ethephon, ripening, yield acceleration, quality