(亚洲棉×司笃克氏棉)不同倍性杂种一代的育性和花粉母细胞减数分裂行为的研究

COMPARATIVE CYTOGENETICS AND FERTILITY OF DIPLOID AND AMPHIPLOID IN F_1 HYDRID 〈G.ARBOREUM X G.STOCKSII〉

亚洲棉与司笃克氏棉杂交,获得了125粒杂种种子,用0.05%秋水仙素水溶液处理,获得7株加倍的四倍体F_1植株。1984-1987年的研究结果表明,二倍体F_1花粉母细胞减数分裂不正常,中期Ⅰ染色体构型是20.53Ⅰ+2.45Ⅱ+0.19Ⅲ,二价体交叉频率为1.07;后期Ⅰ和后期Ⅱ染色体分向两级不均衡,产生各种类型的异常四分孢子,由此发育的花粉无生活力,用亚洲棉回交或自然授粉均未结铃。四倍体F_1减数分裂较正常,中期Ⅰ染色体构型为0.1Ⅰ+25.9Ⅱ,二价体交叉频率为1.96,后期Ⅰ和后期Ⅱ染色体走向两极较均衡,产生的花粉部分可育,授陆地棉花粉或自然授粉能结少数种子。

Gossypium arboreum was crossed as the female parent to G. stocksii. 125 hybridseeds were obtained in 1984, producing seven amphiploid plants after the seeds weretreated with colchicine. The pollon mother cells from the diploid plants of F_1 hybridwere observed during meiosis, and the chromosome configuration at motaphase Iwas 20.53I+2.45II+0.19III on average. with the mean number 1.07 chiasmate perbivalent. Because chromosomes at anaphase I and II were unequally distibuted to cellpoles, tetraspores were abnormal resulting highly sterile male gametes. Where as thechromosome configuration of the amphiploid F_1 at metaphase I was 0.1I+25.95II,with 1.98 of chiasmate per bivalent. The chromosomes were divided equally at ana-phase I and II and pollens were partly fertile. When allowed to open pollinate orbackcrossed to G. arborum, diploid F_1 hybrid plants failed to produce seeds. Butamphiploids produced seeds, in both open-pollinated plants or ones derived from crossto upland cotton.