【作者】 王英；

【导师】 黎志康；

【作者基本信息】 中国农业科学院 ， 作物遗传育种， 2013， 博士

【摘要】 水稻是世界上重要的粮食作物之一，在耕地资源有限，人口不断增加的条件下，提高粮食产量已经成为亟待解决的重要问题。然而随着气候变化等不利因素的影响，干旱、盐害两大非生物胁迫已经造成水稻严重减产。培育具有高产、抗旱和耐盐水稻品种是减轻这两种逆境危害和提高水稻产量最经济有效的措施。本研究以黄华占为轮回亲本，全球水稻分子育种计划中的4个种质材料（OM1706，岗46B，IR64，CR203）为供体亲本培育回交导入系，经高产、抗旱、耐盐筛选和交叉鉴定，获得高产、抗旱、耐盐导入系，以及具有两种及两种以上优良性状的导入系，并对不同选择策略进行评价。同时，以不同性状的选择群体为研究材料，定位高产、抗旱、耐盐以及产量相关性状的QTL，鉴定出在不同群体和环境下稳定表达的增加高产、抗旱和耐盐性的重要等位基因，为分子标记辅助育种提供有益信息。主要获得以下研究结果：1、从高产选择群体中共获得3个生长季均稳定高产株系4个，抗旱选择群体中连续4个生长季均表现抗旱的株系4个，对耐盐选择群体三次鉴定中均表现耐盐的株系111个。2、通过交叉鉴定，13个株系两年均表现高产兼耐盐，5个表现抗旱兼耐盐。综合正常灌溉和干旱胁迫条件下所有选择群体在不同环境下的表现，海南环境下获得既高产又抗旱的株系19个，包括耐盐选择群体中获得的11个，高产群体中获得的1个，抗旱群体中获得的7个；北京环境下获得既高产又抗旱的导入系18个，包括耐盐选择群体中获得的5个，高产群体中的6个，抗旱群体中获得的7个。3、目标性状的筛选受到环境与供体的影响，相比之下，高产和耐盐性相对稳定。在黄华占背景下，海南和北京灌溉条件下的高产筛选以供体CR203对高产贡献最大；温室与人工气候室两种环境中，耐盐性贡献最大供体均为IR64；抗旱性则受环境影响较大，海南干旱胁迫条件下，供体OM1706对抗旱性影响较大，北京干旱胁迫条件下，岗46B对抗旱性贡献最大。4、不同的筛选方式对提高目标性状的效果不同，先进行抗旱或耐盐筛选，再进行高产筛选比直接进行高产筛选获得高产株系的比例要高；同样，对群体进行抗旱直接筛选，或先进行耐盐筛再进行抗旱筛选，获得的抗旱株系的比例要大于从高产群体中筛选抗旱株系的比例。先进行耐盐筛选再进行高产或抗旱筛选的策略不仅增强了株系的耐盐性，而且也提高了高产和抗旱性。5、采用选择导入法，分别检测到与高产、抗旱和耐盐性相关的位点15、13和16个，分布于12条染色上。通过对相应群体的随机群体进行单方差分析，某些与目标性状选择相关的偏分离位点在单方差分析中也得以验证，并估算了基因的加性效应。两种方法共同定位到的位点比较可靠，可以作为是影响目标性状的重要QTL。6、检测到高产、抗旱和耐盐三个性状遗传重叠的位点2个；高产、耐盐遗传重叠位点2个；高产、抗旱遗传重叠位点3个；抗旱、耐盐遗传重叠的位点2个。不同群体定位到与高产、抗旱和耐盐性相关的相同位点个数分别为2、1和3个；同一性状，在两个群体中均检测到的位点有6个，包括与RM219和RM527/RM24连锁的2个高产QTL，与RM335连锁的1个抗旱位点；以及与RM490、RM482和RM574/RM437连锁的3个耐盐QTL。同一群体中两年稳定表达的位点有7个，包括2个抗旱位点（qDT2.2和qDT6.2）和5个高产位点（qGY1.1, qGY6.1, qGY7.1, qGY5.3和qGY3）。7、对产量相关性状QTL定位发现，海南、北京正常灌溉和干旱胁迫条件下，4个群体中检测到15个位点的供体等位基因分别有利于提高千粒重、实粒数、总粒数、有效穗数中的两个或多个性状。其中同时在两个群体中检测到的有qFGP2.2，qFGP10.3，qSNP2.1，qSNP10.2。北京和海南两种环境下均检测到的QTL，包括在正常灌溉条件检测到qGW2.3，qSNP1.4，qSNP2.1，qSNP7.2，qPN4.2，qSNP1.1和qSNP10.2。qSNP10.2的供体等位基因在正常灌溉和干旱胁迫条件下均增加总粒数。上述这些位点均是影响产量或产量相关性状稳定表达的重要位点。8、标记RM576、RM263、RM24、RM182、RM126、RM484不仅与控制高产、抗旱和耐盐性的QTL连锁，而且与控制产量构成因素的QTL连锁，表现出抗逆性之间及其与高产的遗传重叠，更重要的是与这些标记连锁的QTL在两种环境和两个群体或两种检测方法中被稳定检测到，这些位点上的供体等位基因对提高水稻产量、抗旱和耐盐性起积极作用，对分子标记辅助选和聚合育种有重要的参考价值。更多还原

【Abstract】 Rice is one of the most important crops in the world. With unceasing increase of population underlimited land resources, it has been urgent to improve grain yield nowadays. However, with the influenceof unfavorable factors such as climate drought and salinity are becoming two detrimental abioticstresses which have caused serious deduction of rice production. Development of drought tolerance (DT)and salt tolerance (ST) rice variety is a most economic and effective way to minimize their damage andimprove grain yield.In the present study, backcross introgression lines (ILs), which were derived from Huanghuazhan(HHZ) as the recurrent parent, and four germplasm including OM1706, Gang46B, IR64and CR203asdonor parents, were used to develop high yiled (HY), DT and ST ILs through screening against GY, DTand ST and intercross identification, resulting in some ILs with two or multiple favorable target traits.Different selection strategies were then evaluated for their breeding efficiency. Meanwhile, QTLs forHY, DT and ST were detected using different trait-specific ILs, and some important favorable allelesstably expressed in different populations and environments were identified, providing some beneficialinformation for marker-assisted breeding for the three complex traits. The main results were describedas follows:1. Four ILs showing consistent HY across3growing seasons were obtained from HY selected ILs,4lines showing consistent DT across4growing seasons from DT selected ILs,111lines showingconsistent ST in three repeatedly experiments from ST selected ILs.2. By intercross screening,13lines showed HY and ST,5showed DT and ST. According toperformance of selected ILs under normal irrigated and drought stress conditions,19lines were selectedas HY and DT in Hainan condition, including11from ST selected ILs,1from HY selected ILs, and7from DT selected ILs. Similarly,18lines were selected as HY and DT in Beijing condition, including5from ST selected ILs,6from HY selected ILs, and7from DT selected ILs.3. Trait-specific selections are dependent on environment and donor. Relatively speaking,screening of HY and ST is more stable than that of DT. Using HHZ as a recipient, the donor CR203showed most contribution to HY in Hainan and Beijing environments; IR64showed most contributionto ST in green house and phototron conditions; OM1706showed most contribution to DT under Hainandrought stress condition whereas Gang46B showed most contribution to DT under Beijing droughtstress condition.4. Different screening ways showed various selection effectiveness of improving the target traits.First DT or ST then following HY screening would obtain more numbers of HY ILs than direct HYscreening does. Similarly, Direct DT screening or first ST then DT screening would get more numbersof DT ILs than screening DT from HY selected IL populations. The strategy of first ST then HY or DTscreening resulted in not only increased ST but also improved HY and DT.5. By selective IL mapping method total of15,13and16loci were detected and distributed all12chromosomes for HY, DT and ST, respectively. Through single marker analysis for corresponding random populations, some distorted loci associated with the target traits were repeatedly mapped andconfirmed and their additive effects were also estimated. Those loci detected by above two methods arerelatively durable, thus being probably more important QTLs underlying the target traits.6. Two genetic overlapping loci were detected for HY, DT and ST, two for HY and ST, three forHY and DT, and two for DT and ST. There were common2,1and3loci detected in differentpopulations for HY, DT and ST, respectively. There were six loci detected in the two populations for thesame trait, including two HY loci linked with RM219and RM57, one DT locus associated with RM335,and three ST loci associated with RM490, RM482and RM574/RM437. There were seven loci stablyexpressed in the same population across two years, including2DT loci (qDT2.2and qDT6.2) and fiveHY loci (qGY1.1, qGY6.1, qGY7.1, qGY5.3and qGY3).7. QTL mapping indicated that the donor alleles at15loci detected in the four populations undernormal and drought stress conditions in Hainan and Beijing were favorable to improve two or multipleyield component traits such as thousand grain weight (TGW), filled grains per panicle (FGP), spikeletnumber per panicle (SNP) and panicle number per plant (PNP). Among them, qFGP2.2，qFGP10.3，qSNP2.1and qSNP10.2were simultaneously detected in the two populations, and donor alleles atqSNP10.2increased SNP in both normal and drought stress conditions. Above loci are important stablyexpressed loci affecting yield or yield-related traits.8. The markers RM576, RM263, RM24, RM182, RM126and RM484were associated not only withHY, DT and ST, but also with QTLs underlying yield component traits, showing genetic overlapbetween abiotic stress tolerance and HY. More importantly, the QTLs associated with these markerswere all detected by two methods under two environments and/or two populations. The donor alleles atabove loci play an active role in improvement of HY, DT and ST, thus they have important value inmarker-assisted selection and pyramiding breeding in rice.更多还原