目前，在我国北方梨树生产中，极早熟品种（果实发育期８０ｄ以内，在辽宁兴城地区果实７月底前成熟）不多。为繁荣果品市场和提供育种材料，我们对国家梨种质资源圃中的一些极早熟品种，进行了比较观察，并参照以往资料作如下介绍（各品种的某些生物学特性见表１）。１保... At present, in the pear production in northern China, very early varieties (fruit development period within 80d, in Xingcheng, Liaoning fruit mature by the end of July) is not much. In order to prosper the fruit market and provide breeding material, we compared some very precocious varieties in National Pear Germplasm Resources Garden and introduced the following with reference to previous data (some biological characteristics of each variety are shown in Table 1). 1 ...