低度盐胁迫下高粱苗期相关性状的QTL定位

QTL Mapping for Traits Related to Salt Tolerance at Seedling Stage of Sorghum under Low Salt Stress

盐胁迫是盐碱地高粱生产中重要的限制因子。为了更好地了解盐胁迫下高粱苗期耐盐分子遗传机制,服务于高粱耐盐分子育种,本研究利用粒用高粱石红137和甜高粱L-甜杂交衍生的181个重组自交系群体,通过对正常生长条件(0.0%NaCl)和盐胁迫(0.3%NaCl)下的苗高、苗鲜重和苗干重进行调查,利用复合区间作图方法,在正常生长条件下分别检测到3和2个控制苗高和苗干重的QTL;在盐胁迫下分别检测到7、2和2个控制苗高、苗鲜重和苗干重的QTL。其中控制苗高的qSH1-1,在正常生长条件和盐胁迫下均可检测到。与正常生长条件相比,检测到6个盐胁迫下控制苗高的特异表达位点。苗鲜重和苗干重在正常生长条件和盐胁迫下受不同QTL控制。本研究表明,长时间低度盐胁迫可显著抑制高粱幼苗生长,在盐胁迫下控制高粱苗高、苗鲜重和苗干重QTL的表达具有较强的环境特异性,而控制高粱苗高的qSH1-1和qSH7-2在高粱耐盐遗传改良中将发挥重要作用。

Salt s tress is a major limitation for sorghum production. To better understand the molecular genetic mechanism and to service molecular breeding for salt tolerance of sorghum, 181 recombinant inbred lines（RILs）derived from Shihong137 and L-Tian were used in this study. Quantitative trait loci（QTLs） for seedling height,seedling fresh weight and seedling dry weight were analyzed under normal（0.0% NaCl） and salt stress（0.3%NaCl） condition by composite interval mapping method. Three and two QTLs controlling seedling height and seedling fresh weight were identified under normal condition, respectively. Seven, two and two QTLs controlling seedling height, seedling fresh weight and seedling dry weight were identified under salt stress, respectively.Among them, q SH1-1 could be detected under both conditions. Six QTLs controlling seedling height showed salt specific expression under salt stress. Seedling fresh weight and seedling dry weight were controlled by different QTLs under normal and salt stress condition, respectively. Our research indicated that growth of sorghum seedlings was significantly inhibited by long-term salt stress. QTLs controlling seedling height, seedling fresh weight and seedling dry weight showed significantly specific expression under salt stress. q SH1-1 and q SH7-2could play an important role in genetic improvement for sorghum salt tolerance.