以 3 5个不同栽培类型的小麦品种 (系 )作为试验材料 ,根据其 6叶幼苗的根系形态性状进行聚类分析 ,供试材料的根系类型分为 3种 :大根系、小根系和中间型根系。具有中间型根系的材料反复干旱存活率最高 ,这些材料的根系特点是单株根数 7～ 8.5条 ,最大根长 2 0～ 2 2 cm,根总干重 44～ 48mg,其中 1 0 cm以下根干重占 3 6 %～ 45 % ,根冠比范围在 0 .2 2～0 .2 4。一些水地栽培的育成品种苗期抗旱性较强 ,旱地栽培的育成品种苗期抗旱性差异较大 ,个别旱地栽培的地方品种在土壤水分胁迫条件下反而比在正常水分条件下的根系发育更好 ,可能是长期适应干旱条件的结果 A total of 35 wheat cultivars (lines) with different cultivars were used as experimental materials. According to the morphological characters of 6-leaf seedlings, cluster analysis was conducted. The root types of the tested materials were divided into three types: large root system, small root system and intermediate type Root system. The materials with intermediate roots had the highest survival rates under repeated droughts. The root characteristics of these materials were single root number 7 ~ 8.5, maximum root length 20 ~ 22 cm and total root dry weight 44 ~ 48 mg, of which 10 cm Root dry weight accounted for 36% ~ 45%, and root / shoot ratio ranged from 0.22 ~ 0.24. Some cultivars cultivated in water have strong drought resistance at seedling stage, and drought-tolerant cultivars cultivated in dry land differ greatly in seedling stage. Some cultivated landraces cultivated in dry land are more developed under soil water stress than under normal water conditions Well, it may be the result of long-term adaptation to drought conditions