Abstract: A doubled haploid population including 110 lines derived from the inter-subspecific cross between Azucena and IR64 were used to investigate six physiological traits of rice at the heading stage under drought stress and normal irrigation in 2004 and 2005. The changes in all the six traits were analyzed by t-test,as well as the correlations between the traits and drought resistance coefficient (DRC). Based on the genetic linkage map with 175 RFLP markers,QTLs associated with these traits were identified and analyzed. The results indicated that the proline content in rice leaves was significantly (P<0.01) increased,whereas,the relative water content,water potential,chlorophyll content and stomatal conductance of rice leaves significantly (P<0.01 or P<0.05) decreased under the drought stress compared with those under normal irrigation conditions. The relative water content and the water potential were significantly and positively correlated with DRC under the drought stress. Seven QTLs with additive effects and 31 pairs of QTLs with epistatic effects for the six physiological traits related to drought resistance were detected under the two water regimes. In the detected QTLs,two QTLs with additive effects and nine pairs of QTLs with epistatic effects showed QTL×environment interaction effects. There were obvious differences between QTLs under the two water regimes,which indicates that the drought stress has a remarkable effect on the expression of genes controlling the physiological traits related to drought resistance in rice. Among the physiological traits,more QTLs were detected for the stomatal conductance (three additive QTLs and eight pairs of epistatic QTLs),and for the water potential (eight pairs of epistatic QTLs). In addition,drought-resistant rice breeding through molecular marker assisted selection had also been discussed.

Key words: physiological characteristic, drought resistance, molecular marker, rice, quantitative trait locus

摘要： 利用籼稻品种IR64和粳稻品种Azucena杂交产生的包含110个加倍单倍体株系的群体，在干旱胁迫和正常水分条件下，连续在2004年和2005年于抽穗期分别测定了叶片水势、相对含水量、叶绿素含量(SPAD值)、游离脯氨酸含量、气孔导度和蒸腾速率，并于成熟期取样，计算抗旱系数。与正常水分状况下相比，干旱胁迫条件下叶片的游离脯氨酸含量的增加达极显著水平，干旱胁迫条件下叶片的相对含水量、水势、叶绿素含量和气孔导度的降低均达显著或极显著水平。相关分析表明，在干旱胁迫条件下，叶片相对含水量、叶片水势与抗旱系数呈显著或极显著正相关。 利用175个RFLP标记构建的遗传连锁图谱分析了与抗旱性相关的叶片生理指标，共检测到与抗旱性相关的6个生理指标的7个加性QTL，31对上位性QTL，其中有2个主效QTL、9对上位性QTL存在环境互作效应。在两种水分条件下检测到的QTL结果有较大差异，说明干旱胁迫对控制与抗旱性相关的叶片生理性状基因的表达有显著的影响。在6个抗旱相关生理指标中，检测到的控制叶片气孔导度和水势的QTL较多，有3个加性QTL和8对上位性QTL控制气孔导度，有8对上位性QTL控制水势。

关键词: 生理特性, 抗旱性, 分子标记, 水稻, 数量性状座位