【作者】 陈远孟；

【导师】 李杨瑞； 李容柏；

【作者基本信息】 广西大学 ， 作物栽培学与耕作学， 2007， 博士

【摘要】 香稻是栽培稻的特殊类型，香米在国际稻米贸易市场上起着重要作用。Basmati香米以其一流的品质及独特的香味而举世闻名，印度等南亚国家作为Basmati系列香稻遗传多样性中心，拥有类型丰富的香稻种质资源。因此，引进一批南亚香稻资源并加以研究利用，不仅是对我国香稻资源的有益补充，而且对改良我国香稻品种有着重要意义。本研究利用SSR分子标记对引进的南亚香稻资源和广西种植的部分香稻品种及广西非香地方栽培稻资源进行研究，主要包括香味基因的分子标记与定位、香稻的遗传多样性分析、香稻的居群分析、香稻育种核心种质的初步构建等方面内容，获得如下研究结果：1．利用优质稻“中大14”作为母本，南亚香稻UPRB45作为父本，用BSA法构建F₂作图群体。在F₂分离群体中对220个单株进行香味鉴定，卡方测验表明，非香株与香株分离比例符合3:1的分离规律，说明香稻UPRB45的香味遗传受一对隐性基因控制。对南亚香稻UPRB45香味基因进行初步定位，发现水稻第8染色体上的RM223和RM7356与香味基因连锁，与香味基因的遗传距离分别为5.3 cM和11.0 cM。2．不同类组香稻的Nei’s遗传距离估算表明，传统的南亚香稻种质UPRH系列的遗传距离为0.78，改良的南亚香稻B系列的为0.69，广西种植的香稻和非香地方栽培稻的分别为0.59和0.58，说明传统的南亚香稻的遗传多样性显著大于改良的南亚香稻，改良的南亚香稻B系列的多样性又显著大于广西当前种植的香稻种质和广西非香地方栽培稻种质，可见外引南亚香稻种质具有丰富的遗传基础。3．比较了78份来自南亚的香稻资源和18份广西种植的香稻的遗传多样性，结果表明：在南亚的香稻资源中，每对引物检测到的等位基因数为3～13个，平均每个位点的等位基因数为5.31个；在广西的香稻资源中，每对引物检测到等位基因数2～9个，平均每个位点的等位基因数为3.44个；南亚香稻资源平均多态信息含量（PIC）为0.55，广西香稻资源平均PIC为0.41；南亚香稻资源平均基因多样性（Hs）为0.60，广西香稻资源平均Hs为0.47；说明南亚香稻资源比广西香稻资源具有更为丰富的遗传多样性。4．聚类结果分析表明：利用16个SSR标记可以明显地把香稻与非香稻品种聚类为两大类；在78份外引香稻种质中，在遗传距离分别为0.64和0.56处，43份和14份各自聚为一类，总共占73.1％；18份与广西种植的香稻品种聚类，占23.1％；3份与广西非香地方栽培稻品种聚为一类，占3.8％。聚类结果表明，大部分南亚香稻资源或大部分广西香稻资源各自聚为一类，说明大部分南亚和广西的香稻种质资源存在遗传差异性和地理远缘性。5．用5对与香味基因连锁的SSR标记对广西种植的香稻、非香地方籼型栽培稻、非香地方粳型栽培稻以及南亚香稻UPRB系列、UPRH系列、B系列共6个居群进行遗传多样性分析。结果表明，6个居群在第8染色体的遗传多样性以南亚香稻B系列居群的最大；聚类表明，南亚香稻居群与广西水稻居群各自聚为一类。这说明南亚香稻与广西水稻种质在水稻第8染色体上同样存在遗传差异，也证明了南亚香稻类群的独特性。6．结合原群体的地理来源、粳籼类型等分析，用多次聚类法初步构建香稻育种核心种质，经过4次聚类抽样，最终获得24份香稻育种核心种质资源。核心种质的平均等位基因数、有效等位基因数、总遗传多样性指数、平均基因多样性指数、基因分化系数分别为5.25、3.265、0.8656、0.6509、0.2478；而原群体的相应参数分别是6.25、3.348、0.8883、0.6525、0.2659，表明所构建的核心种质与原群体的遗传多样性参数非常接近，说明构建的香稻育种核心种质很好地代表了原群体的遗传多样性，可以在香稻育种实践中应用。更多还原

【Abstract】 Aromatic rice falls into the specialty category of cultivated rice. Aromatic rice isplaying a vital role in the international paddy rice trade market. Basmati rice is a type ofaromatic rice, grown mostly in India and Pakistan. It is renowned for its superfine grainqualities, distinct aroma and extra-elongation during cooking. South Asian countriesincluding India are the genetic diversity center of basmati rice. There is a fair aromaticrice germplasm in South Asian countries. It might be important for beneficialsupplement of aromatic rice and improvement of aromatic rice in our country tointroduce and make use of a series of aromatic rice genotypes from South Asiancountries. The objective of the present study was to reveal the molecular markers linkedto fragrance gene （fgr） and mapping of fgr, genetic diversity, population relationships,and core collection for breeding aromatic rice among aromatic rice genotypes fromSouth Asia and Guangxi of China, and non-aromatic native cultivars from Guangxi ofChina by using SSR primers. The main results of the study were presented as follows:1. A F₂ population, non-aromatic elite rice zhongdal4 as the female parent andaromatic rice UPRB45 from South Asia as male parent, was constructed by bulkedsegregant analysis （BSA）. The fragrance of 220 single plants in F₂ population was tested.The ratio of 3: 1 for non-aromatic to aromatic plants indicated that a recessive nucleargene controlled the aromatic character in the aromatic rice UPRB45. Total 384 pairs ofSSR primers located on 12 chromosomes of rice genome were used for PCR to parentsand F₂ population. The results showed that two SSR markers RM223 and RM7356 onchromosome 8 were linked with the fragrant gene. The genetic distance of the two SSRmarkers to the fragrant gene was 5.3 cM and 11.0 cM, respectively.2. Nei’s genetic distance of UPRH group （traditional aromatic rice from South Asia）, B group （evolved aromatic rice from South Asia）, and aromatic and non-aromatic nativecultivars from Guangxi of China was 0.78, 0.69, 0.59 and 0.58, respectively. Analysis ofNei’s genetic distance showed that genetic diversity in South Asia traditional aromaticvarieties was significantly larger than that in the South Asia evolved aromatic varieties,while that in the evolved aromatic varieties from South Asia was significantly largerthan that in the aromatic varieties and non-aromatic native germplasm being planted inGuangxi. These study results indicated much rich genetic basis in the aromaticgermplasm from South Asia.3. Genetic diversity of 96 rice genotypes included 78 aromatic rice genotypes fromSouth Asia and 18 aromatic rice genotypes from Guangxi was assessed. A total of 85 and55 alleles were present in South Asia and Guangxi aromatic rice at the 16 SSR loci,respectively. The number of alleles per locus for respectic South Asia and Guangxiaromatic rice ranged from 3 to 13 and from 2 to 9 with an average of 5.31 and 3.44, andthe polymorphism information content （PIC） values ranged from 0.171 to 0.872 andfrom 0.099 to 0.765 with an average of 0.55 and 0.41, and the average geneticmultiplicity index （Hs） values ranged from 0.184 to 0.884 and from 0.105 to 0.792 withan average of 0.60 and 0.47, respectively. The results indicated the genetic diversity washigher in the aromatic rice germplasm from South Asia than that from Guangxi.4. The results of cluster analysis on the aromatic and non-aromatic rice genotypeswith 16 SSR markers showed the aromatic and non-aromatic varieties were basicallyclustered into two groups. Among the 78 aromatic varieties introduced from abroad, 57or 73.1% were clustered into a group, 18 or 23.1% clustered together with 14 Guangxiaromatic varieties, whereas only 3 or 3.8% clustered together with 24 Guangxi nativenon-aromatic varieties at the genetic distance 0.56. The cluster analysis indicated thatmost of the aromatic rice germplasm from South Asia or from Guangxi could beobviously confined to one cluster respectively. And the genetic and geographicaldifferences lied between the aromatic rice germplasm from South Asia and those fromGuangxi.5. The genetic diversity of six populations was evaluated by using 5 SSR markerslinked to fgr, which included the aromatic rice, non-aromatic indica and japonicapopulations from Guangxi, and UPRB, UPRH and B populations from South Asia aromatic rice genotypes. The highest genetic diversity for chromosome number 8 wasdetected among the B population. The genetic relationships among the 6 populationswere obtained by POPGENE analysis based Nei’s genetic distance. The 6 populationswere clustered into two groups. Group I comprised the aromatic rice, non-aromaticindica and japonica populations from Guangxi. GroupⅡincluded UPRB, UPRH and Bpopulations from South Asia aromatic rice genotypes. This suggested that the geneticdifference lied between the aromatic rice genotypes from South Asia and that fromGuangxi. The genetic relationships among the 6 populations indicated that the aromaticrice genotypes from South Asia had developed a special aromatic rice type.6. Based on Nei-Li similarity coefficients matrix, japonica-india type andgeographical resource of original collection, the preliminary core collection for breedingaromatic rice, comprised of twenty-four rice genotypes, was constructed after four-timeclusters. The average number of alleles per locus, effective number of alleles per locus,total index of gene diversity, average index of gene diversity and coefficient of genedifferentiation is 5.25, 3.265, 0.8656, 0.6509 and 0.2478, respectively, in the corecollection; while 6.25, 3.348, 0.8883, 0.6525 and 0.2659, respectively, in original collection.The results indicated the genetic diversity between the core collection and the originalcollection was very similar, and the established core collection could represent thegenetic diversity of the original collection. It could be applied in breeding aromatic rice.更多还原