Cytological and molecular studies on genomic exchange and reconstitution in the synthetic allotetraploid cucumis hytivus

采用细胞学和分子标记方法对甜瓜属人工异源四倍体（C. hytivus Chen and Kirkbride，2n = 4x = 38）的亲本染色体组间的交换重组进行了研究。通过对减数分裂中期I染色体行为观察，在108个花粉母细胞中有50个细胞具有多价体，占46.3%，染色体的平均构型为0.56I+17.36II+0.35III+0.26IV+0.046V+0.056VI，表明两亲本染色体组间发生了广泛的重组交换。通过对446条随机引物进行筛选，有5条引物扩增出6条C. hytivus特征带。选取其中3条转换成SCAR标记，对13种甜瓜属不同基因型材料的DNA进行扩增，结果仅有SAP-03/700标记表现为特异性。进一步分析这一标记在人工异源四倍体（C. hytivus）、栽培黄瓜（C. sativus var. sativus）及野生黄瓜（C. sativus var. hardwickii）中扩增出的3条不同分子量条带序列，发现两端序列较为一致，中间部分不同，与黄瓜线粒体基因组序列有200 bp左右的大小相同，但方向相反。 The exchanges and reconstitutions between the two genomes in the allotetraploid Cucumis hytivus Chen and Kirkbride (2n = 4x = 38) were investigated by cytological and molecular means. Among the 108 pollen mother cells (PMC) observed, 50 PMC (about 46.3%) had multivalents, indicating the wide genomic exchange and reconstitution. The average chromosome configuration was 0.56I+17.36II+0.35III+0.26IV+0.046V+0.056VI. Among 446 arbitrary primers, only 5 primers could produce 6 specific bands of C. hytivus. Three of them were selected and converted into s