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1.
End-use quality of wheat for noodles is influenced by polyphenol oxidase activity and its corresponding substrates. This study investigated the chromosomal location of genes that determine phenol colour reaction of kernels in tetraploid wheat using aneuploid stocks. Polyphenol oxidase activity was estimated by the colour reaction of kernels to phenol solution. It was found that the genes located on homoeologous group 2 chromosomes have an important effect on the level of phenol colour reaction of kernels. The genes (Tc1 and Tc2) responsible for high phenol colour reaction of kernels were mapped to the long arms of chromosome 2A and chromosome 2B, respectively. The map distances were estimated to be 46.8 cM for Tc1 and 40.7 cM for Tc2 from the centromere using double-diltelosomics of durum wheat. 相似文献
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【目的】黄瓜（Cucumis sativus L.）遗传基础狭窄,种质资源多样性较为有限,遗传育种研究相对落后。本试验旨在创制整倍体和非整倍体黄瓜种质材料,建立其准确的染色体组成鉴定方法,为进一步选育黄瓜各种染色体系、目标性状的染色体定位及遗传育种研究奠定基础。【方法】以华北生态型黄瓜‘长春密刺’的高代自交系为材料,0.4％秋水仙素溶液处理萌动种子,诱导染色体数目加倍。为获得同源三倍体材料,以诱导获得的同源四倍体为母本,二倍体为父本进行杂交,授粉35-45 d后采收成熟果实进行胚拯救。采用染色体计数,结合形态学、叶片气孔电镜观察,对诱导株及杂交后代的倍性进行鉴定。利用染色体特异的探针进行荧光原位杂交（fluorescence in situ hybridization,FISH）,通过观察特异探针在染色体上杂交信号的数目、强弱及位置,结合黄瓜的染色体形态参数,对诱导株的染色体组成进行鉴定。【结果】对经秋水仙素处理的‘长春密刺’材料进行有丝分裂中期染色体计数观察,结果显示诱导获得8株四倍体（2n=28）,3株非整倍体（2n=16,19,27）材料。将四倍体与二倍体杂交获得了三倍体材料（2n=21）。经荧光原位杂交分析,根据黄瓜着丝粒探针Type III和核糖体45S rDNA两类信号在染色体上的信号特征可以看出,与二倍体相比,三倍体与四倍体上杂交信号为倍性变化关系,进一步验证创制出的整倍性材料为三倍体与四倍体。不同倍性‘长春密刺’植株的形态学特征存在一定差异,四倍体植株的形态指标与二倍体差异显著;三倍体植株与二倍体在形态学上差异不显著;非整倍体植株与二倍体在形态学上差异也不显著,但其长势较二倍体弱,且花期推迟,雌雄花花期不遇,坐果率明显低于二倍体。经叶片气孔电镜观察,‘长春密刺’二倍体、三倍体与四倍体植株叶片气孔的大小与密度均存在差异,随着倍性提高,气孔的长度和宽度增加,而气孔密度则下降,说明形态学筛选和叶片气孔电镜观察可以作为鉴定黄瓜倍性的辅助方法。以上述两类黄瓜重复序列（Type III和45S rDNA）和染色体特异的单拷贝基因Csa006700为探针,对染色体数目为16的一株非整倍体诱导株进行染色体组成鉴定。重复序列的荧光原位杂交结果显示,额外的两条染色体为1号或2号染色体。进一步利用黄瓜2号染色体端部的基因Csa006700探针检测,发现该基因只在其中一对染色体上有信号,由此明确该材料为附加两条1号染色体的四体材料（2n=14+2）。研究表明秋水仙素不仅可直接诱导出同源多倍体,同时可诱导各种非整倍体植株。【结论】利用秋水仙素处理黄瓜萌动种子,诱导染色体倍性的变化,结合染色体特异探针的荧光原位杂交鉴定,可快速创制并筛选出各种染色体组成的特异新种质。 相似文献
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通过空间诱变得到半矮秆突变体hya 1,该突变体半矮秆性状遗传稳定性丧失。与其野生型特籼占13相比,hya 1株高显著降低、分蘖少、茎秆细弱、每穗粒数减少、结实率降低、发芽率降低。单株收获半矮株hya 1自交种子,对半矮生性状进行连续选择,发现该性状无法纯合稳定,自交群体株高长期分离（半矮秆和野生型）;分离群体中的野生型个体自交,其株高性状稳定。利用hya 1与特籼占13配制杂交组合,其F1及F2株高表型不符合孟德尔分离规律。hya 1自交收获种子根尖细胞染色体数目出现了2n=22、23、24、25、36的变异,且在减数分裂终变期发现了二价体数目为11的异常花粉母细胞。荧光定量结果表明, hya 1自交后代野生型个体12条染色体的基因拷贝数与对照接近,而半矮秆个体在第8和第11染色体上的基因拷贝数与对照存在显著差异。综合以上结果,推断hya 1为水稻新型非整倍体材料,其染色体数目异常导致表型异常和遗传不稳定性,对其深入研究有助于了解水稻减数分裂分子调控机理。 相似文献
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雄性三倍体虹鳟(Oncorhyncus mykiss)可以发育至生理成熟并表现出较强的雄性副性征,性腺发育基本正常;雌性三倍体虹鳟性腺几乎不发育,并且存在着类雄性化的发育趋势.本研究拟通过对虹鳟杂交胚胎(2n♀×3n♂)发育状况及其DNA倍性的分析,进而确认三倍体虹鳟是否具有与二倍体虹鳟类似的生育能力并分析其原因.选取经两个世代家系选育的虹鳟优良品系二倍体雌性虹鳟作为母本,以热休克方法人工诱导的优质雄性三倍体虹鳟为父本,常规人工采集精卵授精,获得三倍体雄性与二倍体雌性杂交胚胎,观察杂交胚胎的发育进程,通过流式细胞仪检测杂交胚胎的DNA含量,进而与二倍体雌雄交配获得的胚胎对照确定杂交胚胎的倍性.结果表明,杂交胚胎的受精率、发眼率和孵化率均显著地低于对照组,杂交胚胎多数在发眼期之前死亡,破膜的胚胎在仔鱼期上浮前全部死亡.杂交胚胎的DNA含量分布范围较大,大致可以分为两个水平,接近84％的胚胎的DNA含量介于二倍体与三倍体之间,约为对照组DNA含量的2.5倍;约有16％的胚胎的DNA含量在三倍体和四倍体之间.本研究认为,染色体非整倍体化可能会引起杂交胚胎细胞核质不相容,进而导致基因表达调控紊乱,从而使杂交胚胎不能正常发育,无法完成由母体卵黄供给的内源营养向外源营养的转换,成为导致杂交胚胎发育过程中大量死亡,以及杂交仔鱼在破膜之后开始进食之前全部死亡的一个重要原因. 相似文献
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Summary Karyotypes, chromosome association and pollen fertility of aneuploid varieties (2n=25), Ochibagoromo, Matsusakatsukasa and Isehomare in Iris ensata were analysed and compared with those of eu-diploid varieties (2n=24), Shishinden, Kachô and Asahimaru. The somatic chromosome complement of the aneuploid varieties consisted of 11 pairs and 3 singles of chromosomes and that of the eu-diploid varieties 12 pairs of chromosomes. The singles of chromosomes in the aneuploid varieties had similarity with one another and with a pair of chromosomes in the eu-diploid varieties. The high frequency of normal association was present in the eu-diploid varieties, and this indicated that 12 pairs of chromosomes had full homology between each other. In contrast, the mean chromosome association per cell in an aneuploid variety Ochibagoromo was 4.615I+10.067II+0.077III+0.005IV, indicating that the chromosome complement of this variety consisted of 11 pairs and 3 singles and that these singles had partial homology among them. The eu-diploid varieties exhibited high pollen fertility due to their regularity of chromosome association; the aneuploid varieties considerably lower fertility, i.e. 28.2% for Ochibagoromo, 31.8% for Isehomare and 43.8% for Matsusakatsukasa. The primary cause for the low fertility of these varieties seemes to be the partial homology among 3 single chromosomes. Finally, the origin and the development of the aneuploid varieties were discussed. 相似文献
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Summary In order to elucidate the mechanism of low fertility of Brassicoraphanus, i.e., amphidiploids between Brassica japonica Sieb. and Raphanus sativus L., the chromosome number of 253 plants was studied during the 3rd–9th generations for their seed fertility. Meiotic irregularity showed no connection with degree of sterility. Brassicoraphanus consisted of euploids (2n=38), hyperploids (2n=39–43) and hypoploids (2n=34–37) with white or yellow flowers. The number of plants was highest in euploids and became lower as the chromosome number diverged from the euploid number. Further, seed fertility was highest and the range of its variation widest in euploids. The seed fertility of aneuploids became lower and its variation narrower in proportion to the number of chromosomes additional to or missing from the euploid number. Yellow-flowered plants were superior in seed fertility to white-flowered plants. Seed fertility of plants is primarily affected by their chromosome numbers and secondarily modified by genic effects. As a whole, seed fertility of Brassicoraphanus increased gradually and its variation widened with the advance of generations. This was explained mainly by the increase of balanced combinations of genes. 相似文献
8.
Liguleless phenotypes of wheat lack ligule and auricle structures on all leaves of the plant. Two recessive genes principally control the liguleless character in tetraploid wheat. The F2 progenies of k17769 (liguleless mutant)/Triticum dicoccoides and k17769/T. dicoccum segregated in a 15:1 ratio, whereas the F2 progenies of k17769/T. durum and k17769/T. turgidum segregated in a 3:1 ratio. A new gene, lg3, was found on chromosome 2A. Segregation of F2 progenies between k17769 and chromosome substitution lines for homoeologous group 2 chromosomes suggested that the liguleless genotype had occurred by mutation at the lg3 locus on chromosome 2A, and then by mutation at the lg1 locus on chromosome 2B, in the process of domestication of tetraploid wheat. The gene (lg1) was linked to Tc2 (11.9 cM), which determines phenol colour reaction of kernels, on the long arm of chromosome 2B. The distance of lg1 to the centromere was found to be 60.4 cM, and microsatellite mapping established the gene order, centromere – Xgwm382 – Xgwm619 – Tc2 – lg1 on the long arm of chromosome 2B. 相似文献
9.
Telosomic mapping of the homoeologous genes for the long glume phenotype in tetraploid wheat 总被引：1，自引：0，他引：1
Triticum turgidum ssp. polonicum and T. ispahanicum were characterized by the long glume phenotype. P
1 gene determines the long glume phenotype of T. polonicum, and locates on chromosome 7A. T. ispahanicum has shorter glume than T. polonicum and the long glumephenotype is determined by P
2 gene located on chromosome 7B. In the present study, aneuploid stocks of `Langdon' durum wheat were used to map the genes, P
1 and P
2. P
1 located on the long arms of chromosome 7A and its map distances from the centromere was 14.5 cM. On chromosome 7B, four loci located as cc (chocolate black chaff) – Pc (purple culm) – centromere – P
2 – cn-BI (chlorina). P
2 located on the long arms of chromosome 7B and its map distances from the centromere was 11.7 cM. It was suggested that a paralogous gene set conditions long glume phenotype in the homoeologous group 7 chromosomes. The P
1 and P
2 genes may be useful as genetic markers in tetraploid wheat. 相似文献
10.
微卫星分离模式显示雄性三倍体鲫产生非整倍体精子 总被引：1，自引：1，他引：0
三倍体鲫(Carassius auratus)行天然雌核发育,其自然种群中却有较高比例的雄性个体,这些雄性个体的性腺发育正常,能产生有活力的精子。而且其精子的DNA含量约为体细胞的一半,显示三倍体鲫精子发生过程中可能经历了均等的减数分裂。流式细胞术虽然能够较准确地测定细胞群的平均DNA含量,但是却很难检测到单个精子中的个别染色体增减,要明确回答雄性三倍体鲫产生的精子是否为整倍体需要定量地检测单个精子的遗传组成。本研究用微卫星标记检测以雌性鲤(Cyprinus carpio)与雄性三倍体鲫为亲本构建的杂种家系的基因型,结果发现母本鲤的多态位点在子代中呈孟德尔分离,父本三倍体鲫具有三套鲫基因组,其等位基因在子代中呈随机分离。上述研究结果提示:三倍体鲫起源于二倍体鲫的同源加倍,而非二倍体鲫和鲤的种间杂交;三倍体鲫通过染色体的随机分离产生非整倍体的精子,其精子发生过程中没有均等的减数分裂。三倍体鲫行雌核发育生殖,却可能并非起源于种间杂交且群体中的雄性个体可育,因而是单性生殖鱼类中的一个特例。 相似文献