水稻第2染色体上抗旱相关性状QTL的精细定位

Fine Mapping of Drought Resistance QTL on Chromosome 2 in Rice

因水资源危机水稻抗旱性的遗传与育种研究成为当今的研究热点之一。鉴定与水稻抗旱性直接相关的性状和产量的QTL,可为通过标记辅助选择培育抗旱水稻品种提供标记信息。以从供体IRAT109导入到珍汕97B背景的269个高代近等基因系中筛选出覆盖第2染色体目标区段的87个近等基因系为材料,在抗旱鉴定大棚中采用控制式供水,精细定位了水处理(对照)与干旱胁迫条件下影响水稻水分生理及产量相关性状的QTL。共检测到20个影响叶水势(LWP)、冠层温度(CT)、茎基粗(BCT)的相关QTL和百粒重(HGW)、每穗颖花数(SN)、着粒密度(SPD)等产量相关QTL。根据在不同环境下的表达情况将其分为3类,第1类7个QTL,在2种环境下均被检测到;第2类4个,只在对照条件下检测到;第3类2个,分别控制叶水势和茎基粗,受干旱胁迫诱导,只在胁迫条件下被检测到,其中,叶水势定位在RIO02037-RIO02038约8.2kb的区段上,其加性效应和贡献率分别为1.0361和13.03%,增效等位基因来自IRAT109;茎基粗定位在RIO02017-RIO02022约37.7kb的区段内,加性效应和贡献率分别为0.2682和49.20%,增效等位基因来自珍汕97B。在水、旱2种条件下均检测到的相对稳定的7个QTL及干旱胁迫条件下的2个QTL可能对抗旱性有直接贡献。

In rice breeding research, drought resistance （DR） is one of the most important target traits for variety improvement under ever-increasing severe drought situation in the whole world. Identification of the physiological character and grain yield QTLs directly related to DR will provide useful marker information for developing with DR rice variety via marker-assisted se- lection （MAS）. The 87 introgression lines （ILs） selected from 269 advanced backcross introgression population derived from Zhenshan 97B/IRAT109 in the Zhenshan 97B background were planted in drought facilities for mapping QTLs affecting physio- logical characters and grain yield under irrigation and drought stress conditions. Twenty QTLs affecting leaf water potential （LWP）, canopy temperature （CT）, basal culm thickness （BCT）, 100-grain weight （HGW）, spikelets number per panicle （SN）, and spikelets density were identified, which could be grouped into three types based on their behaviors. Type I included seven QTLs which were detected under both conditions; type II consisted of four QTLs which were mapped only in the control condition; and type III consisted of two QTLs which were induced by drought and detected only under the stress. The seven QTLs detected under both environments and the two QTLs detected under drought stress could directly contribute to DT and be used in rice breedingfor DT by MAS.