1996～1977年卢龙县引进中玉4号杂交玉米种进行了试验示范，发现其最大特点是在涝洼地同样可实现高产。据调查：该品种在涝洼地种植每667mt平均产量5096公汀，最局出这672．8公片，严重后参试品种技单13、唐母2（白粒）、京丹901三个品种之首。1997年在大区试验中，该品种产量 From 1996 to 1977, Lulong County introduced Zhongyu 4 hybrid maize to carry out experimental demonstration, and found that its most prominent feature is that it can also achieve high yield in waterlogging depression. According to the survey: the varieties planted in waterlogged depression per 667mt average yield of 5096 ginseng, the most out of this 672.8 tablets, the serious test varieties after the test single 13, Tang mother 2 (white tablets), Kyudan 901 three varieties First of all. In 1997 in a large area experiment, the variety yield