西藏辣椒地方品种资源综合评价及优异品质基因挖掘

Tibet has rich resources of pepper landraces, most of which are featured with special flavor. They serve as a raw material for traditional local food and some of them have become a local characteristic industry, bearing a double function to meet the demand of people’s consumption and economic growth. However, performance degradation and poor quality arose from unreasonable seed reserve and extensive cultivation management, which negatively influence the realization of their functions. A systematic research of local variety resources has great significance in both developing local economy and meeting the demand of the local residents. However, few studies were done on this topic. This project aims for a thorough collection of pepper landraces resources in Tibet and a comprehensive analysis of the genetic diversity, cultural characteristics, yield, quality and pest resistance, and then to screen for high quality genetic resources. The study is expected to: (1) ascertain the current situation of pepper landraces in Tibet, and analyze the overall performance of each accession and the degree of genetic diversity based on SSR markers; (2) select 2-3 lines with outstanding quality performance and overall performance, and obtain 3-5 intermediate breeding materials; (3) to find SNP loci and candidate genes significantly associated with quality traits such as capsaicin using genome-wide association studies (GWAS) in Tibet pepper landrace resources. The study is expected to provide technical support for local social and economical development, and provide excellent germplasm materials for pepper breeding in China.

西藏有丰富的辣椒地方品种资源，多数具有特殊风味，是当地传统美食素材，部分品种已成为地方特色产业，承载着满足当地人民消费需求与经济增长双重功能。但不合理留种及粗放式栽培管理使多数品种出现种性退化、品质变差，影响其功能的实现。系统研究西藏地方品种资源对发展当地经济、满足人民需求具有重要意义，但目前对此鲜见研究报道。本项目拟全面搜集西藏辣椒地方品种资源，并从遗传多样性、栽培特性、产量、品质及抗逆抗病虫性等方面进行综合评价，在此基础上挖掘优异品质基因资源。以期:（1）探明西藏辣椒地方品种资源现状，分析各品种综合性能，基于SSR阐明其遗传多样性程度;（2）筛选出2-3份品质性能突出、综合性状良好的优异品种，获得3-5份育种新材料;（3）在全基因组范围内寻找与西藏辣椒地方品种辣椒素等品质性状显著关联的SNP位点与候选基因。研究结果可望为西藏地方社会经济发展提供技术支撑，为我国辣椒育种提供优异种质材料。

为全面了解分布于西藏各地的辣椒地方品种资源情况，并通过研究为有效开发利用这类资源提供技术支撑，在项目实施期内结合实际，从西藏辣椒地方品种资源的考察收集，部分地方品种资源的品质分析、肥料施用、抗性鉴定、光合特性，部分地方品种辣味基因表达谱分析及辣椒传入西藏的传播途径等研究，取得主要结果如下：.1.收集到西藏辣椒地方品种36份，分布于日喀则市（吉隆县、亚东县、定结县）、山南市（错那县，聂拉木县樟木镇应该有分布）、昌都市（芒康县、左贡县）、林芝市（察隅县、米林县、波密县、墨脱县、巴宜区、朗县），基本摸清了西藏辣椒地方品种资源状况。.2.认为辣椒传入西藏的渠道可能有两种，一种是从印度、尼泊尔等国通过边境线传入，另一种是通过茶马古道传入（察隅或昌都）。.3.初步筛选出了2份品质性状优异的地方品种，1份光合效率高的地方品种，2份在种子萌发期耐低温强的地方品种，2份抗蚜虫性和抗灰霉病、早疫病优异的地方品种。.4.在对部分辣椒地方品种辣椒素含量测试基础上从转录组分析和辣味合成相关的基因及表达分析方面开展了辣味基因表达谱分析，初步筛选出8个与辣椒素类相关的差异表达基因，推测出LOC107857229、LOC107870553、LOC107849953、LOC107851643、LOC107854372、LOC107867296、LOC107843092等7个调控辣椒素类物质积累的重要基因。.5.在复合肥施用量90.34kg/hm2基础上，施用腐熟牛粪572m3/hm2时朗县辣椒表现出较好的生长发育状态，有较高的产量和较好的品质，是朗县辣椒在林芝地区栽培时适宜的农家肥施用量，而以16.875kg-33.75kg/亩的量是“米林羌纳辣椒”、“朗县朗镇辣椒”、“墨脱甘登辣椒”等地方品种优质高效栽培的氮肥适宜用量。