【作者】 刘忠；

【导师】 廖明安；

【作者基本信息】 四川农业大学 ， 果树学， 2012， 博士

【摘要】 中国是世界荔枝(Litchi chinensis Sonn.)的起源中心和荔枝栽培驯化的发源地。从海南岛到长江上游的河谷地带均有荔枝分布,有2000多年的栽培历史和丰富的种质资源。近年来,我国对荔枝资源的研究主要集中在广东、广西和福建等纬度较低地区。而对分布在北界-长江上游地区的荔枝研究甚少,尤其是对所属岷江下游的荔枝种质资源缺乏系统研究。该地区由于地理、气候等与华南地区差异较大,是荔枝资源分布比较特殊的地区,该地区的荔枝资源是我国荔枝资源的重要组成部分,对其研究是十分必要的。为此,通过2006-2011年实地调查和室内分析,考查了现有岷江下游荔枝古树的分布情况并研究了它们的种质特点,通过其果实形态特征对岷江下游荔枝古树资源进行了初步的分类；对该地区所引种荔枝的生物学和农艺学性状进行了比较研究,并对适宜品种进行了筛选。同时采用SRAP分子标记对岷江下游荔枝资源进行了遗传多样性分析。本研究对发展该地区的荔枝产业具有重要理论和实践意义。主要研究结果如下：1、通过实地调查,对岷江下游地区荔枝的分布区域进行了系统研究,全面调查了岷江下游荔枝古树资源的分布情况。结果表明,荔枝古树资源主要分布在岷江下游的犍为县、乐山市市中区、乐山市沙湾区、夹江县、洪雅县。目前有658株荔枝古树。沿岷江及其支流的河谷地带分布。纬度范围29°05’N-29°48’N,海拔320m至600m。历史上分布的眉山、成都、雅安等地已经没有了荔枝古树的踪迹。根据调查荔枝古树果实的形态特征初步将岷江下游的荔枝古树种质资源分为挂绿、合江荷包荔枝、转窝子荔枝、白荔枝、乌泡和酸荔枝6种类型,其中属于果皮龟裂片隆起,龟裂纹明显,裂片峰尖锐的有2种；属于果皮龟裂片平坦、龟裂纹明显、无裂片峰的有2种,其中1种裂片峰有刺状感；属于龟裂片隆起,龟裂纹明显,裂片峰钝圆的有2种。2、岷江下游荔枝古树为高大乔木,树体高多超过10m,板根发达,树冠浓郁、宽广。树龄高,100a以上,最大超过300a,干周大,最大3.05m,羽状复叶,小叶3-5对,以4对为主,小叶有对生和互生,以对生为主,小叶长7.00-15.00cm,小叶宽2.50-5.00cm；根据对荔枝古树形态特征,古树间于野生和栽培荔枝之间。岷江下游荔枝古树4月上旬开花,5月上旬花期结束。果实成熟期6月下旬至7月上旬。果实形状多样,有近球形、心形、椭圆形等多种形态,果皮有红色、紫红色、有红绿、红黄绿杂合的多种颜色。荔枝古树果实单果重为9.2-25.5g,可食率为45.3-72.9%,焦核率为0-30%,Vc含量为25-39mg/100ml果汁。3、利用SRAP对41份荔枝古树资源和3份引种荔枝包括合江大红袍、糯米糍和楠木叶为试验材料,选用32对SRAP引物进行PCR扩增,共检测出222条清晰条带,其中产生182条多态性条带,多态率为81.9%。32对引物组合遗传多样性在0.0329(me22/em19)～0.4990(me21/em18)之间,平均为0.2915,表明岷江下游荔枝资源遗传多样性较低,遗传基础较为狭窄。44份材料相似系数在0.5586-0.9279,平均相似系数为0.7913,根据荔枝种质之间的遗传相似系数,利用UPGMA (Unweighted pair group method arithmetic average)进行聚类分析,获得了一个丰富的聚类图。岷江下游荔枝古树可在相似系数0.67处划分出4个大组,已经发现的6种类型分属与四个组中。进一步可以划分出更多的小类,从分子生物学角度证明岷江下游荔枝种质资源存在遗传多样性。聚类分析表明,岷江下游荔枝古树资源与引进的合江荔枝包括合江大红袍、合江糯米糍、楠木叶之间的遗传相似系数较高。表明合江荔枝与岷江下游的荔枝古树资源之间有一定的亲缘关系,但可以在相似系数0.67处明显区分。4、对1980年代、1990年代从合江县引入的鹿沃、合江大红袍、合江糯米糍、楠木叶四个品种在岷江下游的栽培表现进行了观察比较。研究表明：鹿沃结果率很低,合江糯米糍虫害严重。以合江大红袍和楠木叶适宜于岷江下游乐山、犍为等地栽培,能正常的生长、开花、结果。合江大红袍表现最佳。合江大红袍在4月下旬开花,7月中旬成熟,16a龄果树的平均株产为54kg、平均单穗重860g、平均单果重26g。楠木叶在4月下旬开花,8月中旬成熟,成熟期晚。23a龄果树平均株产25Kg、平均单穗重518g、平均单果重18.5g。对荔枝发梢抽穗规律进行研究发现,荔枝在岷江下游一年内会多次抽梢,并且不规则。比较了夏梢、秋梢等作为结果母枝的抽穗、开花、结果情况。传统以春梢和夏梢作为结果母枝,容易发冬梢而抽穗率低。而以晚夏梢和早秋梢作为结果母枝,其抽穗、开花、结果率较高。5、对岷江下游危害荔枝的病虫害调查结果表明岷江下游荔枝的主要虫害有14种,分属昆虫纲5目7科13种,蜘蛛纲1科1种。其中危害最为严重的是荔枝细蛾Conopomorpha sinensis Bradley,荔枝蝽象Tessaratoma papillosa(Drury)和星天牛Anoplophora macularia (Thompson)。更多还原

【Abstract】 China is the origin center of litchi (litchi chinensis Sonn.) and important commercial production region in the world. Litchi trees are widely distributed in the rainforest of Hainan island located in the south of China to the Yangtze river. There were abundant germplasm resources in China with a long history, more than2000years. During the recent decades, the study on the germplasm resources of litchi were mainly concentrated on the southern area including Guangdong, Hainan province and the Guangxi autonomous region of China. However, the upper reach of Yangtze river, as well as the north boundary of litchi distribution is another special area with a long history of litchi cultivation. There was rarely research on the litchi germplasm resources distributed especially in the lower reach of Minjiang river, one tributary of the Yangtze river. The basic research on litchi germplasm resource was extremely necessary for breeding and local litchi industry. Hence, an investigation on the distribution of the germplasm resource was carried out from2006-2011in the lower reach of Minjiang river. The classification for the old litchi trees was studied according to the fruit characteristics. The genetic diversity of these litchi germplasm was analyzed by Sequence-related amplified polymorphism (SRAP). And the investigation was carried out for cultivar introduction from Hejiang county, Sichuan province. The main results were as follow:1. The distribution of the ancient litchi trees in the lower reach of Minjiang river was mainly in the center district, Shawan county of Leshan city, the Qianwei county, Jiajiang county and Hongya county, which located in from29°05’N to29°48’N. At last, six hundred and fifty eight ancient litchi trees were found. This district belongs to the narrow valley area along the Minjiang river and its tributaries as Dadu river and Qingyi river. However, there was no living litchi trees in the district such as Chengdu, Meishan, Yaan city where litchi trees were found long before. According to the characteristics of the fruit exocarp, these germplasms could be classified into6types including Gulv, Hejianghebaoli, Wupao, Zhuanwozi, Bailizi, and Suanliz. Two of them characterized with the protruding and hard protuberances. Two of them were belong to the group which the protuberances were sparse or hairlike, fine or sharp pointed. Two of them were in the group which the protuberances were smooth or not evident.2. The ancient litchi trees found in the lower reach of Minjiang river characterized with tall plant above10m, developed roots system and thick canopy. These ancient trees were above100years old, and the oldest one may be over300years. The largest trunk girth was3.05m. The pinnate is with3-5pairs leaflet arranging opposite or alternate. The length of the leaflet varied from7cm to15cm and the width of the leaflet varied from2.5cm to5.0cm. The florescence of the ancient litchi was from the early April to the early May.The maturity date focused on from the late June to the middle of July.The shape of the fruits collected from the ancient litchi trees showed oval, heart, long-egg round, nearly round, ellipse and etc. The color of the fruit exocarp appeared red, dark-red, yellow and combined colors as red-yellow, red-green and others. The average fruit weight varied from9.2g to25.5g. The edible rate of the fruits varied from44.3%to72.5%.The rate of aborted seed was0%-30%. The vitamin C content of fruit juice was between25mg/100ml to39mg/100ml.3. In the present paper,41samples collected from the ancient litchi trees and3another cultivars including Hejiang dahongpao, Hejiangnuomici and Nanmuye introduced from Hejiang county, Sichuan province were analyzed with SRAP (Sequence-related amplified polymorphism). Thirty-two SRAP primer combinations were used and182polymorphic bands out of222were observed with an average of5.6per primer combination. The genetic diversity ranged from0.0329to o.4990, with an average level of0.2913. The unweighted pairgroup method arithmetic average (UPGMA) analysis demonstrated that the accessions had a similarity range from0.5586to0.9279with a mean value of0.7913. And there were four clusters at the similarity level of0.6700, indicating more extensive genetic variation among ancient trees. The cluster analysis results showed that the ancient litchi resources in lower reach of Minjiang river might share close relationship each other. Nevertheless, the Sul(Gualv) collected from Zhangba village, Suji town could be singly classified one group. The others as Hejiang Hebaoli,Wupao, Zhuanwozi, Bailizi, and Suanlizi were clustered in the other2groups. The cluster analysis indicated that there might be more litchi types among the ancient litchi trees. It was certain that there could be some special germplasm resources of litchi in the lower reach of minjiang river valley for further breeding and biodiversity conservation. The Clustering analysis showed that the three cultivars introduced from Hejiang county including Hejiang Dahongpao, Hejiang nuomici and Nanmuye were distinctly separated from the ancient trees and could be classified into the same group at the0.6700level for similarity.4. Four cultivars including Hejiang Dahongpao, Hejiang Nuomici, Luwo and Nanmuyewer were introduced from Hejiang county in1980s,1990s respectively. The investigation on biological and agronomical characteristics demonstrated that Hejiang Nuomici, Dahongpao,Luwo and Nanmuye litchi trees could show normally growth and development. However, the Luwo was fruitless, amd Hejiang Nuomici suffered from severe pest disease. Comparably, the Hejiang Dahongpao was the best one among the introduced cultivars with flowering in April and maturing in July. As for16-years-old tree, the average fruit yield of per tree, average weight per fruit fringe and per fruit weight were54Kg,860g and26g, respectively. Also Nanmuye, a late mature cultivar of23years old, produced fruits in the mid-August with mean weight25Kg per tree,518g per fruit cluster and18.5g of per fruit.The introduced cultivars could often generate shoots for several times in one year, but developing irregularly. The shoots germination, the formation of inflorescence and the process of fruiting from different types of shoots had been investigated. Traditionally, the shoots generated in spring and summer were the bearing fruit branch. The investigation results showed that the shoots generated in the late summer and early autumn which formed inflorescence easily and bear more fruits than other type of shoots.5. The main species and epidemiologic characteristics of litchi pests in the lower reach of Minjiang river were also investigated. Fourteen species of litchi pests were found, belonging to insecta,5items,7families,13species and arachnida,l family,1species. The main pests including Conopomorpha sinensis Bradley, Tessaratorna papillosa (Drury), Anoplophora macularia (Thompson) were the serious threaten to the local litchi industry.更多还原