长江流域夏秋茎用莴苣栽培比较普遍，一般在立秋前后低温催芽，遮阳网覆盖播种育苗，在秋季凉爽天气下抽笋膨大。但若将其播种期提前至大暑前后，则极易发生先期抽笋，笋细长而失去商品性，给生产造成损失。为此，1997－1998年在我院蔬菜园安排了夏秋望用莴苣品比试验，以期为 Summer and fall stems lettuce cultivation in the Yangtze River Basin is relatively common, usually in the pre-autumn and early post-emergence germination, shade net cover sowing seedlings, in the autumn cool weather bamboo shoots swollen. However, if the sowing period is advanced before and after the big summer, it is extremely prone to early shoots, shoots slender and loss of merchandise, resulting in loss of production. To this end, 1997-1998 in our hospital vegetable garden arranged summer and autumn lettuce ratio test to