甘薯栽培种及其近缘野生种的DAPI核型及rDNA-FISH分析

摘要

Ipomoea batatas cv. Xushu 18 and its two wild relatives I. hederacea Jacq. from American and Hong Kong in China were studied by DAPI banding and rDNA-fluorescence in situ hybridization. The DA-PI banding showed the karyotype of I. batatas and I. hederacea Jacq. from American and Hong Kong in China are 2n=6x=90 = 72m+18sm(18SAT) with satellites on chromosome 1,3 and 6:2n = 2x=30 = 30m (4SAT);2n=2x=30 = 20m+10sm(4SAT),both with satellite on chromosome 6 and 12,respectively. The FISH data indicated that three pairs of 5S rDNA signals,located on centromere,pericentromere and the te-lomere of chromosome respectively of I. batatas (Two pairs of 45S rDNA signals, located on chromosome 6 and 12 were detected on both I. hederacea Jacq. ; While 1 pairs of 5S rDNA signals presented on chromosome 6 of I. hederacea Jacq. from Hong Kong, 2 pairs of 5S rDNA signals occurred on the chromosome 6 and 12 of that from American. Taking all the data obtained in the study, both I. hederacea Jacq. were distant from the sweet potato, and there were some differentiations in the chromosomes of the I. hederacea Jacq. from different territories.%利用DAPI显带和rDNA-FISH技术对栽培种甘薯(‘徐薯18’)(Jpomoea batatas cv.Xushu No.18)及2种不同产地近缘野生种(Ipomoea hederacea Jacq.)进行了细胞遗传学研究.DAPI核型分析表明,‘徐薯18’核型公式为2n=6x=90=72m+18sm(18SAT),随体位于第1、3、6染色体上;美国近缘野生种核型公式为2n=2x=30=30m(4SAT),香港近缘野生种核型公式为2n=2x=30=20m+ 10sm(4SAT),随体均位于第6、12染色体上.rDNA-FISH结果显示,栽培种甘薯基因组中含有3对5S rDNA位点,分别位于着丝粒区、亚着丝粒区和染色体端部；美国近缘野生种基因组中含有2对5S rDNA位点,香港近缘野生种基因组中含有1对5S rDNA位点,均位于随体部位；两种不同地域来源的近缘野生种基因组中均含有2对45S rDNA位点,分别位于第6和第12染色体上.