Characterization of pepper accessions using molecular markers linked to pungency and SSR

ABSTRACT Peppers of the genus Capsicum are of great socioeconomic importance, being pungency trait their main attraction. Pungency characterization, genetic distance estimates and population structure analysis of the accessions belonging to germplasm banks are important for parent selection which allows to obtain superior progenies. Therefore, the aims of this study were: i) evaluate 81 accessions of the Capsicum spp. Germplasm Bank of Universidade Federal de São Carlos (BGC-UFSCar) with molecular markers linked to pungency; ii) estimate the genetic diversity among accessions of the BGC-UFSCar using microsatellite markers (SSR); and iii) evaluate the efficiency of these markers in the distinction among species of Capsicum spp. We noticed that pun11 and SNP molecular markers were efficient in predicting the pungent phenotype of BGC-UFSCar accessions in 84.85% and 95.59%, respectively. From a total of 13 amplified microsatellite markers, seven were polymorphic and efficient to discriminate species of Capsicum genus, both through genetic diversity analysis and population structure analysis, which showed three subpopulations. The molecular markers used in this study are useful tools for breeding programs since they were able to characterize and discriminate Capsicum spp. species at DNA level. Information obtained with molecular markers can assist in the selection of contrasting parents for future breeding programs.摘要：辣椒属（Capsicum）作物具有极高的社会经济价值，其中辛辣性状是其核心吸引力所在。对种质资源库中的辣椒种质开展辛辣性状鉴定、遗传距离估算及群体结构分析，可为亲本选配提供依据，进而培育出优良后代。为此，本研究达成三大目标：其一，利用与辛辣性状连锁的分子标记，对圣卡洛斯联邦大学（Universidade Federal de São Carlos）种质资源库（BGC-UFSCar）的81份辣椒属（Capsicum spp.）种质进行评价；其二，采用微卫星标记（Simple Sequence Repeat, SSR）估算BGC-UFSCar种质间的遗传多样性；其三，评估上述标记在区分辣椒属物种方面的有效性。研究发现，pun11与单核苷酸多态性（Single Nucleotide Polymorphism, SNP）分子标记分别以84.85%和95.59%的准确率，有效预测了BGC-UFSCar种质的辛辣表型。在共计13个扩增得到的微卫星标记中，有7个具备多态性，且可通过遗传多样性分析与群体结构分析有效区分辣椒属物种，分析结果显示该属可划分为3个亚种群。本研究使用的分子标记可作为辣椒育种项目的实用工具，因其能够在DNA层面实现辣椒属物种的鉴定与区分。通过分子标记获取的相关信息，可为未来育种项目中对比性亲本的筛选提供有力辅助。