Analysis of SSRs Information in Capsicum spp.from EST Database

SSR markers are useful in pepper linkage mapping and gene location.446 SSR markers have been reported,but they are insufficient.It is costly to develop SSR markers from DNA library,whereas it seems much easy to find in EST sequences in the GenBank of pepper through internet.In this study,attempts have been made to develop SSR markers in the EST sequences by using bioinformatics.EST sequences were trimmed by ‘est-trimmer.pl' software,while 116 915 EST sequences were obtained without poly ‘A' or poly ‘T',ranged between 100 and 700 bp.Using ‘e-PCR' and ‘del.pl' softwares,SSR sequences were identified.2 508 microsatellite loci (larger than 20 repeats) were established and 755 SSR primers were designed using SSR finder software and Primer 3 software.There were 498 (0.43％) mono-,1 026 (0.89％) di-,5 1 8 (0.45％) tri-,245 (0.21％) tetra-,114 (0.10％) penta-,and 107 (0.09％) hexa-nucleotide SSRs.The estimated frequency of SSRs was approximately 1/25.12 kb.According to the distribution of SSRs in pepper,the mean length of pepper SSRs was 22.68 bp and the adenine rich repeats such as A/T,AG,AT,AAG,AAAT,and AAAC were predominant in each type of SSRs (mono-,di-,tri-,tetra-,penta-,and hexa-),whereas the C/G,CG,CCG repeats were less abundant.210 primers were tested in 8 pepper cultivars and the PCR result revealed the existence of polymorphism among 127 (60.48％) SSR primers within 8 pepper cultivars.It is confirmed that pepper EST database could be efficiently exploited for availability of SSR markers.     

失水胁迫下辣椒幼苗离体叶片光合作用对弱光的响应

 以弱光耐受性不同的4个辣椒（Capsicum annuum L.）自交系为试材,在人工气候室的受控环境中研究叶片短期离体失水胁迫条件下光合作用对弱光（75～100 μmol·m-2·s-1）的响应。结果表明,对于正常光照或弱光环境下的辣椒幼苗,在轻度和中度水分胁迫下,气孔限制因素是引起叶片光合速率下降的主要因素,而严重的水分胁迫使光合速率大幅度下降则是受非气孔因素的限制。在轻度和中度水分胁迫时,辣椒叶片光合作用对弱光的响应较迟缓,即弱光下光合速率随叶片相对含水量（RLWC）减小而下降的趋势相对缓慢,光合速率对水分的变化不敏感。失水胁迫下辣椒（果实味辣）对弱光的适应性强于甜椒（果实味甜）。弱光环境下生长的辣椒叶片水势较高,水合补偿点有减小的趋势。     

多元统计分析方法在辣椒品种耐盐性评价中的应用

根据NaCl溶液处理下辣椒萌芽期和幼苗期农艺性状指标,采用多元统计分析方法评价辣椒品种的耐盐性。结果表明：辣椒不同品种间,相对发芽势、相对胚根长、相对发芽指数、盐害指数、相对株高等12个性状指标表现出显著性差异;采用因子分析将此12个性状指标用4个主因子表示,保留了原始变量95.35%的信息量;基于品种因子得分值进行聚类分析,10个辣椒品种分为3类：中椒4号、8号、7号、12号为盐敏感品种,中椒5号、11号为中度盐敏感品种,中椒6号、13号、16号、10号为盐不敏感品种。因此,辣椒品种的耐盐性可通过测定萌芽期和幼苗期农艺性状指标,采用多元统计分析方法予以快速鉴定。     

辣椒抗疫病性状遗传及其相关AFLP标记分析

以93-100-17-1-0×茄门组合为基础，建立F2代作图群体。从感受性、诱导性和稳定性等3个方面进行遗传分析，发现93-100-17-1-0的抗疫病性状是由多基因或寡基因所控制的。根据AFLP分析，利用Mapmaker/exp (Version 3.0)作图软件构建辣椒的分子连锁图谱，结合winQTLCART(Version 1.15)，对辣椒抗疫病的基因定位，将与感受性有关的QTL位点定位在第5条连锁群上，与诱导性有关的QTL位点分别定位在第1、第2、第5、第8条连锁群，与稳定性有关的QTL位点定位在第1、第2、第5、第7条连锁群，各QTL位点可解释表型变异率在64%以上。     

Genetic diversity and population structure analysis of Capsicum germplasm accessions

Genetic diversity plays an essential role in plant breeding and utilization. Pepper is an important vegetable and spice crop worldwide. The genetic diversity of 1 904 accessions of pepper conserved at the National Mid-term Genebank for Vegetables, Beijing, China was analyzed based on 29 simple sequence repeat(SSR) markers, which were evenly distributed over 12 pepper chromosomes. The pepper accessions were divided into two groups in a genetic structure analysis, and the two groups showed obvious differences in fruit type and geographical distribution. We finally selected 248 accessions capturing 75.6% of the SSR alleles as the core collection for further research. Insights into the genetic structure of pepper provide the basis for population-level gene mining and genetic improvement.     

3个辣椒花药培养再生株群体主要农艺性状及苗期抗病性研究

对3个辣椒花药培养再生株DH-R2群体的主要农艺性状,包括株高、株幅、首花节位、叶色、单果质量、商品果横径、商品果纵径、果形指数、老熟果色等进行了较详细的测量和统计分析。结果表明:辣椒花药培养再生株群体的农艺性状存在基因型偏性;再生株群体的单果质量、商品果纵径、果形指数这3个性状都表现为低于供体,株高、株幅、首花节位、商品果横径这4个性状都表现为近似于供体;通过单倍体培养途径可以得到不同颜色层次的老熟果色的辣椒纯系,证明了该途径是多基因控制性状育种的有效途径;对耐TMV和CMV的亲本与感病亲本的杂种进行花药培养,获得了兼具TMV和CMV抗性的株系,证明了单倍体培养途径可以创造新的超亲抗病种质。     

辣椒成熟果实中辣椒红素含量的QTL定位

以83-58×Perennial构建的包括138个单株的重组自交系(RIL)群体为作图群体,利用142个SSR标记、24个CAPS标记以及果实辣味、果柄着生方向(pun和up)2个形态标记构建遗传连锁图谱并进行了辣椒成熟果实中辣椒红素的QTL定位。生理成熟期(花后70d)辣椒果实的辣椒红素含量测定值作为QTL定位时的表型数据,利用复合区间作图法共检测到3个QTL位点,分别位于辣椒的第2、10、12条染色体上,分别解释了表型变异的7.6%、8.2%、6.5%。     

“十一五”我国辣椒遗传育种研究进展

"十一五"期间辣椒的遗传育种研究得到了国家、省、部等多个项目支持,在辣椒资源的鉴定和评价、育种技术、材料创新和新品种选育等方面都取得了长足发展,特别是分子标记技术,已应用到资源遗传多样性和遗传分析、辅助育种等多个领域;雄性不育相关研究取得了较大进展,加工育种研究也开始受到重视;培育出一大批类型多样的辣椒新品种。存在的问题主要是遗传资源相对狭窄、创新力度不足、重复研究等,本文展望了"十二五"我国辣椒遗传育种研究的重点。     

辣椒白粉病抗性QTL 定位分析

以辣椒（Capsicum annuum）白粉病抗、感病亲本H3 和83-60 构建的包含142 个重组自交系的RIL（H3×83-60） F8 群体为试验材料,基于亲本重测序数据设计KASPar 引物,构建了包含16 个连锁群的辣椒遗传连锁图谱,总图距1 356.5 cM,标记间平均图距为4.69 cM。基于2016 年和2017 年重组自交系群体白粉病发病表型数据,获得了PMR6.1、PMR9.1、 PMR11.1、PMR11.2 和PMR5.1 等5 个白粉病抗性QTL 位点,其中PMR6.1、PMR9.1 在两年中均被检测到,表型贡献率在 10.8%～21.4% 之间。通过辣椒白粉病抗性QTL 定位,开发与白粉病抗性基因连锁的SNP 分子标记,对于辣椒抗病辅助育 种有重要参考价值。     

花粉直感对普通玉米子粒淀粉含量的影响

以9个淀粉含量不同的玉米自交系为亲本,按照Griffing I双列杂交模式组配72个当代杂交组合,测定子粒淀粉含量,分析花粉直感现象对玉米子粒淀粉含量的影响。结果表明：当同一母本授以不同父本花粉时,当代组合淀粉含量存在明显差异;花粉直感现象对当代子粒的淀粉含量存在正负双向影响,其最大增幅为6.59％,最小增幅-5.00％;高淀粉含量的亲本Lx00-6作父本,所得到当代组合子粒淀粉含量均高于母本。