滇山茶多倍性栽培品种的遗传多样性研究

Camellia reticulata, a Chinese endemic species, the second-class national protected plant, the key of "eight famous flowers" in Yunnan Province, the city flower of Kunming, is famous of high tree and big flower. With complex ploidy, the C. reticulata has about 160 cultivars. In recent years, however, 38 cultivars have lost. Now, more than 40 cultivars' status is still unknown. Thus, the cultivar protection should be strengthened. Meanwhile, the cultivation range of C. reticulata is limited in central Yunnan for long term due to the lack of cultivars of heat resistance and cold resistance. So, the cultivar development is very necessary so as to broaden the market of C. reticulata. The genetic diversity is an important basis for the protection and development of germplasm resources. Therefore, in this project, the genetic diversity of polyploidy cultivars in C. reticulata will be studied by morphology, cell ploidy, genic-SSR fluorescence markers based on transcriptome data, and sequence analysis of nrDNA ITS and cpDNA rpl16. In addition, the cultivar classification system of C. reticulata will be established according to the cell ploidy as "cultivar group". The molecular identity system of C. reticulata cultivars will also be established based on SSR markers. This project will provide the technical basis for the identification and classification of C. reticulata cultivars, and lay the foundation for the protection and development of C. reticulata cultivars, so as to promote the industry of C. reticulata.

滇山茶为中国特有种、国家二级保护植物、云南省八大名花之首、昆明市市花，以树高花大而驰名中外。滇山茶栽培种质的倍性复杂，品种约有160个，但近年已有38个品种相继流失，当前仍有40多个品种现状不明，因此，品种的保护亟待加强。同时，滇山茶因缺乏耐热、抗寒品种，其栽培范围长期受限于滇中地区，为拓宽市场，新品种的开发十分必要。遗传多样性是种质资源保护与开发的重要依据，为此，本项目将综合植株形态观测、细胞倍性鉴定、基于转录组测序开发的genic-SSR荧光标记、nrDNA的ITS与cpDNA的rpl16序列分析，探讨滇山茶多倍性栽培品种的遗传变异水平及其分布格局，并整理出拟以细胞倍性划分“品种群”的滇山茶品种分类系统，构建基于SSR标记的滇山茶品种分子身份证。项目的实施，将为滇山茶的品种鉴定与分类提供技术支撑，为滇山茶的品种保护与开发提供科学依据，进而推动滇山茶产业的持续发展。

滇山茶为中国特有种、国家二级保护植物、云南省八大名花之首、昆明市市花，以树高花大而驰名中外。滇山茶栽培种质的倍性复杂，品种约有160个，但近年已有38个品种相继流失，当前仍有40多个品种现状不明，因此，品种的保护亟待加强。同时，滇山茶因缺乏耐热、抗寒品种，其栽培范围长期受限于滇中地区，为拓宽市场，新品种的开发十分必要。遗传多样性是种质资源保护与开发的重要依据。.本项目对滇山茶品种的遗传多样性进行了较为全面的研究，主要结果如下：.1）通过流式细胞术倍性估计，在63个滇山茶品种中，六倍体29个，占比46.03%；八倍体31个，占比49.21%。十倍体3个，占比4.76%。.2）基于滇山茶转录组和基因组数据开发的5个单拷贝核基因位点（538-1038 bp），对来自昆明、楚雄、大理和保山的100个滇山茶栽培品种进行了测序及分析，结果表明：5个序列的总长度为3,481bp，含71个多态性突变位点（2.04％）和91个单倍型，单倍型多样性为0.9974，核苷酸多样性为0.0077；昆明、楚雄、大理、保山的单倍型多样性分别为1、0.9825、1、0.9957，核苷酸多样性分别为0.0068、0.0066、0.0081、0.0084；栽培区之间的遗传分化系数分别为Fst=0.0199，Nm=12.300；四个栽培区内滇山茶品种的遗传多样性参数水平为：大理>保山>昆明>楚雄；滇山茶品种的遗传变异主要存在于栽培区内，不同栽培区之间的基因交流非常频繁；聚类分析将滇山茶栽培品种分为了四枝，其中三枝分别与异源六倍体滇山茶的三个亲本种（二倍体滇山茶、西南山茶和怒江山茶）成簇；第四支涉及滇山茶的另一未知种源，它可能与异源六倍体滇山茶再次杂交多倍化形成八倍体滇山茶有关。.3）基于叶绿体rpl16内含子的序列分析，结果表明：滇山茶品种的杂交母本种源为滇山茶异源六倍体；异源六倍体滇山茶的母本杂交种源为滇山茶异缘四倍体；滇山茶异缘四倍体的杂交母本种源为西南红山茶。.项目的实施，将为滇山茶的品种鉴定与分类提供技术支撑，为滇山茶的品种起源与演化、保护与开发提供科学依据，进而推动滇山茶产业的持续发展。