城口县位于四川盆地东北边缘,海拔高度在481—2,686米之间。由于山大坡陡日照短,年平均气温在14℃左右,适宜种植洋芋,素有“洋芋半年粮”之说。但当地洋芋品种退化较严重。1979年以来,县农科所开展了洋芋茎尖脱毒的科学实验,用“疫不加”、“雪花白”、“米拉”、“里外黄”等洋芋种籽,进行有性繁殖。通过试管育苗、网厢移栽、原种繁殖,获得的种薯可保持3—5年的良种性能。目前已获得无毒种薯3万多斤,1983年小区推广扩大到85亩,低山收获平均亩产2,500斤,促进了洋芋增产。种植茎尖脱毒洋芋的关键是网室栽培。其栽培方法是: 一、改良土壤,结合消毒。无毒小苗从试管移入网室,需要在表土深厚,结构疏松,排灌方便,通气良好,富于有机质的土壤上培植。若土壤较粘重,应加潮沙泥或干塘泥1寸以上,(耒欠)入土中,然后开沟作厢。厢长7.5尺、 Chengkou County is located in the northeastern edge of the Sichuan Basin, at an altitude of 481-2,686 meters. Due to the steep sunshine short slope, the annual average temperature at about 14 ℃, suitable for planting potato, known as “potato half a year,” said. However, the local potato varieties degenerated more seriously. Since 1979, the county agricultural science and technology to carry out the potato stem tip virus-free scientific experiments, with “no disease”, “Snow White”, “Mira”, “yellow inside” and other potato seeds, sexual reproduction . Through tube nursery, net cage transplanting, breeding of original species, the seed can be obtained to maintain 3-5 years of elite performance. At present, it has obtained more than 30,000 kilos of non-toxic seed potatoes. In 1983, the area was expanded to 85 acres and the average harvest of low mountains was 2,500 kilos, contributing to the increase of potato production. The key to planting stem tip virus-free potato is net room cultivation. The cultivation methods are: First, improve the soil, combined with disinfection. Non-toxic seedlings from the test tube into the net room, you need deep in the topsoil, loose structure, irrigation and drainage convenient, well-ventilated, rich in organic matter in soil cultivation. If the soil is more sticky, should be added tidal mud or dry pond mud more than 1 inch, (owed) into the soil, and then ditched for the box. The car is 7.5 feet long,