1997～ 1 999年选用生产上常用的 1 2个抗热大白菜品种 (系 )在郑州市郊进行的夏大白菜品种比较试验结果表明 :各品种 (系 )的抗热结球能力有一定差别 ,豫园 50、西白 1号、夏优 1号、夏优 2号、优夏王、盛夏六品种 (系 )从 6月中旬到 8月上旬播种结球良好 ;而夏阳 50、亚蔬1号、豫早 1号三品种 (系 ) 7月以后播种结球较好 ;豫早 2号仅能在 8月初播种。随播期的推迟 ,各品种 (系 )产量有增加的趋势。豫园 50、优夏王、夏优 1号可作为推广品种 (系 )在我省推广 ,从 6月上旬到 8月中旬均可播种 ;豫早 1号、西白 1号、新早 89- 8可在 7月上旬至 8月上旬播种 ;豫早 2号只能 8月初作为秋早熟品种栽培 ;夏阳 50和亚蔬 1号干旱年份不宜引种 ;小杂 56应注意病害防治 ;夏优 2号和盛夏则应防止抽薹 The results of the comparative test of summer Chinese cabbage cultivars (strains) with 12 kinds of common heat-resistant Chinese cabbage cultivars (strains) used in the production of 1997-1999 showed that there were some differences in the ability of heat- Yuyuan 50, Xibai 1, Xia You 1, Xia You 2, You Xia Wang, summer six varieties (lines) from mid-June to early August sowing a good ball; and Xia Yang 50, Asia and vegetable No. 1, Yu early on the 1st three varieties (lines) sowing after July is better; Yu early on the 2nd can only be sown in early August. With the postponement of the sowing date, the yield of all varieties (lines) tends to increase. Yuyuan 50, Youxia Wang, Xia You 1 can be used as a promotion of varieties (lines) in our province to promote, from early June to mid August can be sown; Yu early 1, West White 1, 89- 8 Can be sowed in early July to early August; Yu early as early as early August 2 as a precocious varieties of cultivars; summer 50 and Yazhong 1 dry years should not be introduced; small hybrid 56 should be aware of disease prevention and control; Xia You 2 and Summer should prevent bolting