小麦种质芽期和苗期的耐盐性鉴定评价

【目的】研究不同来源小麦种质资源的耐盐性差异,筛选耐盐性较好的品种（系）,探索不同生育期小麦耐盐性鉴定的适合盐浓度,为小麦耐盐鉴定及耐盐小麦品种选育提供参考。【方法】对来源不同的293份小麦种质,在1.5%NaCl盐溶液下进行盐胁迫处理,调查各种质的芽期相对盐害指数;选择芽期相对耐盐指数小于40%的24份小麦资源,在苗期进行不同盐浓度胁迫鉴定,测量不同处理的根长及苗高相对生长率。【结果】筛选出16份芽期相对盐害指数小于20%的高耐盐种质和42份芽期相对盐害指数20-40%耐盐的小麦种质;苗期鉴定表明1.0% NaCl盐浓度为合适的筛选浓度、根长相对生长率为适合的苗期耐盐性鉴定指标,以此为鉴定技术筛选出了Marmin-Minhardi譎44-Minturki和花树蒲两份芽期及苗期均表现耐盐的优异小麦种质;【结论】来源不同的小麦资源中芽期综合耐盐性大小依次为地方品种>国外引进品种>中间试验品系;Marmin-Minhardi譎44-Minturki和花树蒲两份耐盐小麦种质可作为小麦耐盐育种新种质。     

水稻新种质资源的耐盐性鉴定评价

用0.5%的NaCl溶液作灌溉水,对2000-2002年江苏省水稻区域试验参试品系和近年引进的部分水稻种质资源进行苗期耐盐性鉴定.结果表明:株高矮化是苗期盐胁迫的一种形态特征;耐盐性鉴定易受环境影响;就整体而言,籼稻种质资源的苗期耐盐性好于粳稻;综合2年结果,籼156和64608两种质资源的苗期耐盐性较强.     

水稻分蘖期耐盐性鉴定评价方法确立及种质筛选

分蘖期是水稻由秧田生长向本田生长过渡的营养生长关键时期。在盐渍化土壤上种植水稻,分蘖期耐盐性对水稻能否正常生长至关重要。合适的耐盐性鉴定方法是水稻耐盐种质筛选的前提。本研究目的在于通过水稻分蘖期盐浓度梯度筛选试验,明确水稻分蘖期耐盐性鉴定最适盐胁迫浓度和调查时间;利用确立的鉴定方法,筛选出水稻分蘖期耐盐种质。本研究选取具有不同程度耐盐性的26份水稻品种,于2015年和2016年分别在10个和7个盐浓度梯度下,以盐害等级为分蘖期耐盐评价指标,开展水稻分蘖期耐盐性鉴定评价试验。结果表明,在0.5%盐浓度下,处理4～6周后供试种质的盐害等级差异表现为最大,因此认为0.5%盐浓度是水稻分蘖期耐盐性鉴定的最适盐胁迫浓度,盐处理后4～6周是水稻分蘖期盐害等级调查的最佳调查时间。参照国际水稻所提出的水稻分蘖期耐盐性评价标准,本研究对其进行了改进,提出以单株为单位进行水稻分蘖期耐盐性评价方法,利用平均盐害等级评估分蘖期耐盐性。该方法能够方便、准确地评价水稻耐盐性强弱。依据上述确立的水稻分蘖期耐盐性鉴定评价方法,本研究于2017-2019年期间对2886份来自不同生态区域的水稻种质进行分蘖期耐盐性鉴定评价,鉴定筛选出137份耐盐种质,为水稻耐盐遗传机制和育种研究提供资源支撑。     

水稻全生育期耐盐性鉴定评价方法研究北大核心CSCD

土壤盐渍化是危害水稻生产的重要非生物胁迫因素,而遗传改良是提高水稻耐盐性的有效途径之一。全生育期耐盐性是对水稻各生育时期耐盐性的综合反映。科学、准确、高效的水稻全生育期耐盐性鉴定评价方法是水稻耐盐遗传改良必要条件,也是正确判别水稻种质耐盐真实性的关键所在。本研究挑选19份不同耐盐性水稻种质作为研究材料,在正常环境和0.2%、0.3%、0.4%、0.5%、0.6%、0.7%盐处理浓度下,调查11个农艺性状并计算其耐盐系数,运用品种间四分位差法分析,明确水稻全生育期耐盐性鉴定最适浓度。品种间四分位差最大的盐浓度被认为是盐处理最佳浓度;综合多种多元统计分析方法,包括主成分分析、隶属函数分析、回归分析、聚类分析,对水稻全生育期耐盐性鉴定合理评价方法进行探索。结果表明,0.3%盐胁迫浓度下多数性状耐盐系数品种间四分位差最大,0.3%盐胁迫浓度是水稻全生育期耐盐性鉴定最适浓度。主成分分析结果表明,11个农艺性状的耐盐系数可简化为3个主成分。利用主成分贡献率和隶属函数分析,可进一步将3个主成分值简化为水稻耐盐性综合评价指标D值。D值能够简便、准确的评价水稻种质的耐盐性。本研究还利用逐步回归分析,建立D值与11个农艺性状耐盐系数最优线性回归方程:D=-0.365+0.647PL+0.152GP+0.274TW。从该方程可知穗长、穗粒数和总干物重耐盐系数是影响D值的关键指标。利用回归分析建立的模型,可准确完成对D值预测。本研究利用聚类分析,将19份水稻种质耐盐性划分为5个等级,对应于水稻5个耐盐等级划分,即极强、强、中、弱、极弱,可作为其他水稻种质耐盐性评价重要参考。     

黄麻种质芽期和苗期耐盐性的鉴定与评价

本研究以12份黄麻种质为材料,芽期采用萌发实验法、苗期采用营养液栽培法,进行耐盐性鉴定与评价.结果表明:芽期耐盐性鉴定及其耐盐等级划分可以相对盐害率为指标,而苗期则以平均盐害指数为指标.黄麻芽期耐盐性与苗期耐盐性之间存在极显著相关性(r=0.8432**,n=10);经筛选获得了3份高耐盐材料:9511、中黄麻1号、93繁-13,耐盐等级均为1级;1份盐敏感性材料:孟圆,芽期耐盐等级为5级,苗期耐盐等级为4级.     

小麦品种资源耐盐性鉴定

按照农业部行业标准NY/PZT001-2002,对882份小麦品种资源进行耐盐性初步鉴定,筛选出芽期耐盐性为一级的品种328份,苗期和芽期都达到中度耐盐的品种43份。这些品种中很多既具有中度或中度以上耐盐性且具有高产优质等优异特性,如小偃22、新曙光1号等,为小麦耐盐育种提供重要信息。相关分析表明,不同耐盐级别的小麦品种其芽期和苗期耐盐性并没有一致的相关关系,二者并没有可比性,在耐盐种质筛选过程中,都有其本身的意义。     

大豆种质资源耐盐性鉴定与研究

通过对793份大豆种质资源进行芽期耐盐性鉴定,以及部分品种进行苗期和全生育期耐盐性鉴定,筛选出芽期、苗期及全生育期耐盐品种117份、41份和35份。其中有3个品种(WDD1812,晋豆23和晋遗38号)在芽期和苗期都表现高耐盐性;1个品种(晋豆23)在芽期、苗期、全生育期都表现高耐盐性。晋豆23还具有高度抗旱、高抗病毒病、耐红蜘蛛等特性,而晋遗38号来源于晋豆23。芽期或苗期耐盐性为一级的品种,如中黄13、新大豆1号、陕豆125、东农46、东大1号、合丰38等,不但具有高耐盐性,而且具有很好的丰产性,有些品种还具有优质和抗逆等优异的农艺性状。本研究筛选到的耐盐品种将为大豆耐盐育种提供优异的种质资源,同时对大豆全生育期耐盐性鉴定的指标和方法的探讨,将为大豆耐盐性鉴定科学方法的建立提供重要信息。     

利用回交导入系剖析水稻苗期和分蘖期耐盐性的遗传重叠

以籼稻品种IR64为受体,来自伊朗的粳稻农家品种Binam为供体培育的99个BC2F8回交导入系为材料,定位了水稻在2叶1心期和分蘖期控制耐盐相关性状的数量性状基因座（QTL）．共检测到影响苗期叶片盐害级别、幼苗存活天数和地上部钾、钠离子浓度的QTL 13个,影响分蘖期株高、分蘖数和地上部鲜重的QTL 22个．多数分蘖期QTL对盐胁迫表现出明显的表达差异,根据表达情况将这些QTL分成3组,第1组为在对照条件下表达的11个QTL;第2组为在对照和盐胁迫条件下共同表达的5个QTL,其中有3个（QPh5,QPh8,QTn9）在两种环境下的基因效应大小和方向一致,其表达受盐胁迫影响较小;第3组为受盐胁迫诱导表达的6个QTL．检测到13个影响胁迫与对照差值即性状稳定性的QTL,除QPh4,QTn2和QFw2a外,其余10个基因座增加性状稳定性或提高耐盐性的等位基因均来自Binam．上述受盐胁迫影响较小的3个QTL和影响性状稳定性的13个QTL对耐盐性有贡献,属耐盐QTL．比较苗期和分蘖期耐盐QTL的分布,发现多数（69％）影响苗期和分蘖期的耐盐QTL在遗传上相互独立,仅在第1,2,8和11染色体的4个相同或相邻区域定位到影响两个时期的耐盐QTL,表明苗期和分蘖期的耐盐性存在部分的遗传重叠．通过标记辅助选择将苗期和分蘖期的重要耐盐QTL进行累加,或针对苗期和分蘖期的重叠耐盐QTL进行选择,有可能培育出苗期和分蘖期均耐盐的水稻品种．     

水稻全生育期耐盐性鉴定评价方法研究

土壤盐渍化是危害水稻生产的重要非生物胁迫因素,而遗传改良是提高水稻耐盐性的有效途径之一。全生育期耐盐性是对水稻各生育时期耐盐性的综合反映。科学、准确、高效的水稻全生育期耐盐性鉴定评价方法是水稻耐盐遗传改良必要条件,也是正确判别水稻种质耐盐真实性的关键所在。本研究挑选19份不同耐盐性水稻种质作为研究材料,在正常环境和0.2%、0.3%、0.4%、0.5%、0.6%、0.7%盐处理浓度下,调查11个农艺性状并计算其耐盐系数,运用品种间四分位差法分析,明确水稻全生育期耐盐性鉴定最适浓度。品种间四分位差最大的盐浓度被认为是盐处理最佳浓度;综合多种多元统计分析方法,包括主成分分析、隶属函数分析、回归分析、聚类分析,对水稻全生育期耐盐性鉴定合理评价方法进行探索。结果表明,0.3%盐胁迫浓度下多数性状耐盐系数品种间四分位差最大,0.3%盐胁迫浓度是水稻全生育期耐盐性鉴定最适浓度。主成分分析结果表明,11个农艺性状的耐盐系数可简化为3个主成分。利用主成分贡献率和隶属函数分析,可进一步将3个主成分值简化为水稻耐盐性综合评价指标D值。D值能够简便、准确的评价水稻种质的耐盐性。本研究还利用逐步回归分析,建立D值与11个农艺性状耐盐系数最优线性回归方程:D=-0.365+0.647PL+0.152GP+0.274TW。从该方程可知穗长、穗粒数和总干物重耐盐系数是影响D值的关键指标。利用回归分析建立的模型,可准确完成对D值预测。本研究利用聚类分析,将19份水稻种质耐盐性划分为5个等级,对应于水稻5个耐盐等级划分,即极强、强、中、弱、极弱,可作为其他水稻种质耐盐性评价重要参考。     

人工海水胁迫下小麦种质资源的耐盐性筛选与鉴定

利用人工配制的海水筛选耐盐性较好的小麦品种,为沿海滩涂地区的小麦耐盐育种提供重要信息。本研究利用人工海水处理的方法,对363份小麦种质资源进行了芽期耐盐性初步鉴定,筛选出芽期耐盐性为1级的小麦种质28份。进一步对芽期耐盐性较好的48份小麦种质进行了苗期耐盐性鉴定,并对其耐盐指标进行隶属值模糊评价分析,从中鉴定出了2个苗期耐盐性较强的小麦种质,分别为淮麦31和红壳洋麦。依据来源的不同,发现小麦种质资源的芽期耐盐性大小依次为地方品种>育成品种>国外引进品种。小麦芽期与苗期的耐盐性相关分析表明,二者相关性极低(r=-0.0051)。     

Development and high-throughput genotyping of substitution lines carring the chromosome segments of indica 9311 in the background of japonica Nipponbare

Chromosome segment substitution lines (CSSLs) are useful for the precise mapping of quartitative trait loci (QTLs) and dissection of the genetic basis of complex traits.In this study,two whole-genome sequenced rice cultivars,the japonica Nipponbare and indica 9311 were used as recipient and dtonor,respectively.A population with 57 CSSLs was developed after crossing and back-crossing assisted by mo lecular rnarkers,and genotypes were identified using a high-throughput resequencing strategy,Detailed graphical genotypes of 38 lines were constructed based on resequencing data.These CSSLs had a total of 95 substituted segments derived from indica 9311,with an average of about 2.5 segments pet CSSL and eight segments per chromosome,and covered about 87.4％ of the rice whole genome.A multiple linear regression QTL analysis mapped four QTLs for 1000-grain weight.The largest-effect QTL was located in a region on chromosome 5 that contained a cloned major QTL GW5/qSW5 for grain size in rice.These CSSLs with a background of Nipponbare may provide powerful tools for future whole-genome discovery and functional study of essential genes/QTLs in rice,and offer ideal materials and foundations for japonica breeding.     

覆盖野生稻基因组的染色体片段替换系的构建及其米质相关数量性状基因座位的鉴定

染色体片段替换系（CSSL）是基因组水平快速初步定位数量性状基因座位（QTL）的良好材料,而水稻的品质性状是多基因控制的数量性状,因此可用替换系鉴定控制水稻品质性状的QTL。本文用分子标记辅助选择技术（MAS）构建了由133个株系组成的以‘特青’（籼稻品种）为轮回亲本,以海南的一种普通野生稻为供体亲本,覆盖绝大部分野生稻基因组的染色体片段替换系。利用这套替换系,初步定位了控制稻米外观和理化品质性状的15个QTL,为今后水稻品质性状QTL的克隆以及稻米品质相关性状的改良提供了依据。     

A Chromosome Segment Substitution Library of Weedy Rice for Genetic Dissection of Complex Agronomic and Domestication Traits

Chromosome segment substitution lines (CSSLs) are a powerful alternative for locating quantitative trait loci (QTL), analyzing gene interactions, and providing starting materials for map-based cloning projects. We report the development and characterization of a CSSL library of a U.S. weedy rice accession ‘PSRR-1’ with genome-wide coverage in an adapted rice cultivar ‘Bengal’ background. The majority of the CSSLs carried a single defined weedy rice segment with an average introgression segment of 2.8 % of the donor genome. QTL mapping results for several agronomic and domestication traits from the CSSL population were compared with those obtained from two recombinant inbred line (RIL) populations involving the same weedy rice accession. There was congruence of major effect QTLs between both types of populations, but new and additional QTLs were detected in the CSSL population. Although, three major effect QTLs for plant height were detected on chromosomes 1, 4, and 8 in the CSSL population, the latter two escaped detection in both RIL populations. Since this was observed for many traits, epistasis may play a major role for the phenotypic variation observed in weedy rice. High levels of shattering and seed dormancy in weedy rice might result from an accumulation of many small effect QTLs. Several CSSLs with desirable agronomic traits (e.g. longer panicles, longer grains, and higher seed weight) identified in this study could be useful for rice breeding. Since weedy rice is a reservoir of genes for many weedy and agronomic attributes, the CSSL library will serve as a valuable resource to discover latent genetic diversity for improving crop productivity and understanding the plant domestication process through cloning and characterization of the underlying genes.     

Development of Chromosome Segment Substitution Lines Derived from Backcross between Two Sequenced Rice Cultivars, <Emphasis Type="Italic">Indica</Emphasis> Recipient 93-11 and <Emphasis Type="Italic">Japonica</Emphasis> Donor Nipponbare

Chromosome segment substitution lines (CSSLs) are powerful tools for detecting and precisely mapping quantitative trait loci (QTLs) and evaluating gene action as a single factor. In this study, 103 CSSLs were produced using two sequenced rice cultivars: 93-11, an elite restorer indica cultivar as recipient, and Nipponbare, a japonica cultivar, as donor. Each CSSL carried a single chromosome substituted segment. The total length of the substituted segments in the CSSLs was 2,590.6 cM, which was 1.7 times of the rice genome. To evaluate the potential application of these CSSLs for QTL detection, phenotypic variations of seed shattering, grain length and grain width in 10 CSSLs were observed. Two QTLs for seed shattering and three for grain length and grain width were identified and mapped on rice chromosomes. The results demonstrate that CSSLs are excellent genetic materials for dissecting complex traits into a set of monogenic loci. These CSSLs are of great potential value for QTL mapping and plant marker-assisted breeding (MAB).     

Identification of qRBS1, a QTL involved in resistance to bacterial seedling rot in rice

Bacterial seedling rot (BSR), a destructive disease of rice (Oryza sativa L.), is caused by the bacterial pathogen Burkholderia glumae. To identify QTLs for resistance to BSR, we conducted a QTL analysis using chromosome segment substitution lines (CSSLs) derived from a cross between Nona Bokra (resistant) and Koshihikari (susceptible). Comparison of the levels of BSR in the CSSLs and their recurrent parent, Koshihikari, revealed that a region on chromosome 10 was associated with resistance. Further genetic analyses using an F₅ population derived from a cross between a resistant CSSL and Koshihikari confirmed that a QTL for BSR resistance was located on the short arm of chromosome 10. The Nona Bokra allele was associated with resistance to BSR. Substitution mapping in the Koshihikari genetic background demonstrated that the QTL, here designated as qRBS1 (quantitative trait locus for RESISTANCE TO BACTERIAL SEEDLING ROT 1), was located in a 393-kb interval (based on the Nipponbare reference genome sequence) defined by simple sequence repeat markers RM24930 and RM24944.     

Mapping of quantitative trait loci for salt tolerance at the seedling stage in rice

Salt tolerance was evaluated at the young seedling stage of rice (Oryza sativa L.) using recombinant inbred lines (MG RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). 22 of 164 MG RILs were classified as tolerant with visual scores of 3.5-5.0 in 0.7% NaCl. Interval mapping of QTLs related to salt tolerance was conducted on the basis of the visual scores at the young seedling stage. Two QTLs, qST1 and qST3, conferring salt tolerance, were detected on chromosome 1 and 3, respectively, and the total phenotypic variance explained by the two QTLs was 36.9% in the MG RIL population. qST1 was the major QTL explaining 27.8% of the total phenotypic variation. qST1 was flanked by Est12-RZ569A, and qST3 was flanked by RG179-RZ596. The detection of new QTLs associated with salt tolerance will provide important information for the functional analysis of rice salt tolerance.     

Identification of quantitative trait loci associated with salt tolerance at seedling stage from Oryza rufipogon

Soil salinity is one of the major abiotic stresses affecting plant growth and crop production.In the present study,salt tolerance at rice seedling stage was evaluated using 87 introgression lines (ILs),which were derived from a cross between an elite indica cultivar Teqing and an accession of common wild rice (Oryza rufipogon Griff.).Substantial variation was observed for four traits including salt tolerance score (STS),relative root dry weight (RRW),relative shoot dry weight (RSW) and relative total dry weight (RTW).STS was significantly positively correlated with all other three traits.A total of 15 putative quantitative trait loci (QTLs) associated with these four traits were detected using single-point analysis,which were located on chromosomes 1,2,3,6,7,9 and 10 with 8％-26％ explaining the phenotypic variance.The O.rufipogon-derived alleles at 13 QTLs (86.7％) could improve the salt tolerance in the Teqing background.Four QTL clusters affecting RRW,RSW and RTW were found on chromosomes 6,7,9 and 10,respectively.Among these four QTL clusters,a major cluster including three QTLs (qRRW10,qRSW10 and qRTW10) was found near the maker RM271 on the long arm of chromosome 10,and the O.rufipogon-derived alleles at these three loci increased RRW,RSW and RTW with additive effects of 22.7％,17.3％ and 18.5％,respectively,while the phenotypic variance explained by these three individual QTLs for the three traits varied from 19％ to 26％.In addition,several salt tolerant ILs were selected and could be used for identifying and utilizing favorable salt tolerant genes from common wild rice and used in the salt tolerant rice breeding program.     

Comparison of QTLs for rice seedling morphology under different water supply conditions

The variation of seedling characteristics under different water supply conditions is strongly associated with drought resistance in rice (Oryza sativa L.) and a better elucidation of its genetics is helpful for improving rice drought resistance. Ninety-six doubled-haploid (DH)rice lines of an indica and japonica cross were grown in both flooding and upland conditions and QTLs for morphological traits at seedling stage were examined using 208 restriction fragment length polymorphism (RFLP) and 76 microsatellite (SSR) markers. A total of 32 putative QTLs were associated with the four seedling traits: average of three adventitious root lengths (ARL), shoot height (SH), shoot biomass (SW), and root to shoot dry weight ratio (RSR). Five QTLs detected were the same under control and upland conditions. The ratio between the mean value of the seedling trait under upland and flooding conditions was used for assessing drought tolerance. A total of six QTLs for drought tolerance were detected. Comparative analysis was performed for the QTLs detected in this case and those reported from two other populations with the same upland rice variety Azucena as parent. Several identical QTLs for seedling elongation across the three populations with the positive alleles from the upland rice Azucena were detected, which suggests that the alleles of Azucena might be involved in water stress-accelerated elongation of rice under different genetic backgrounds. Five cell wall-related candidate genes for OsEXP1, OsEXP2, OsEXP4, EXT, and EGase were mapped on the intervals carrying the QTLs for seedling traits.     

Comparative QTL analysis of salinity tolerance in terms of fruit yield using two solanum populations of F<Subscript>7</Subscript> lines

Salt tolerance has been analysed in two populations of F₇ lines developed from a salt sensitive genotype of Solanum lycopersicum var. cerasiforme, as female parent, and two salt tolerant lines, as male parents, from S. pimpinellifolium, the P population (142 lines), and S. cheesmaniae, the C population (116 lines). Salinity effects on 19 quantitative traits including fruit yield were investigated by correlation, principal component analysis, ANOVA and QTL analysis. A total of 153 and 124 markers were genotyped in the P and C populations, respectively. Some flowering time and salt tolerance candidate genes were included. Since most traits deviated from a normal distribution, results based on the Kruskal–Wallis non-parametric test were preferred. Interval mapping methodology and ANOVA were also used for QTL detection. Eight out of 15 QTLs at each population were detected for the target traits under both control and high salinity conditions, and among them, only average fruit weight (FW) and fruit number (FN) QTLs (fw1.1, fw2.1 and fn1.2) were detected in both populations. The individual contribution of QTLs were, in general, low. After leaf chloride concentration, flowering time is the trait most affected by salinity because different QTLs are detected and some of their QTL×E interactions have been found significant. Also reinforcing the interest on information provided by QTL analysis, it has been found that non-correlated traits may present QTL(s) that are associated with the same marker. A few salinity specific QTLs for fruit yield, not associated with detrimental effects, might be used to increase tomato salt tolerance. The beneficial allele at two of them, fw8.1 (in C) and tw8.1 (for total fruit weight in P) corresponds to the salt sensitive parent, suggesting that the effect of the genetic background is crucial to breed for wide adaptation using wild germplasm.