同源四倍体水稻恢复系TP-4和D明恢63与保持系D46B的细胞遗传学比较

Cytogenetical comparison of restorers TP-4 and D minghui63 and maintainer D46B of autotetraploid rice

以高结实率的同源四倍体水稻恢复系TP-4和D明恢63及优良保持系D46B为材料进行细胞遗传学研究。所有四倍体材料的染色体组成均为2n=48,这与有丝分裂的结果一致。恢复系TP-4和D明恢63及保持系D46B的中期Ⅰ单价体和三价体的比例都很低,配对染色体的比率在99%以上,具有优良的细胞学特征。恢复系TP-4和D明恢63在中期Ⅰ四价体频率分别为2.00/PMC和2.26/PMC,而保持系D46B在中期Ⅰ四价体频率为6.00/PMC,极显著地高于恢复系品系因而具有更好的染色体配对性质;后期Ⅰ保持系D46B的染色体滞后频率为10.62%,远低于恢复系材料TP-4的19.44%和D明恢63的23.14%,接近二倍体对照明恢63的7.30%水平;末期Ⅰ保持系D46B具有比恢复系更低频率的微核数而末期ⅡD46B的正常四分小孢子比率不但高于恢复系品系甚至高于二倍体对照。相关分析表明后期Ⅰ染色体滞后细胞比率同末期Ⅰ异常细胞比率呈极显著的正相关,推测后期Ⅰ染色体分离和末期Ⅰ微核形成可能是由相同的显性单基因或主效基因控制。

Cytogenetical comparison was made between high seed set restorers TP-4 and D minghui63 and eminent maintainer line D46B of autotetraploid rice. The meiosis observation demonstrated the genomes of our autotetraploid materials were all 2n = 48, the same as those in mitosis observation. Low percentages of univalent and trivalent in metaphase I （MI） of restorers TP-4 and D minghui63 and in metaphase I （MI） of maintainer line D46B of autotetraploid rice were observed. And the percentages of chromosome pairing were all over 99%, showing eminent cytological character. The frequency of TP-4 and D minghui63 in metaphase I （MI） was 2.00/PMC and 2.26/PMC, respectively. However the frequency of D46B was 6.00/PMC, significantly higher than those of TP-4 and D minghui63. It indicated that the maintainer D46B has better chromosome pairing capability in metaphase I （MI）. While, the frequency of lagging chromosomes of the maintainer D46B in anaphase I （AI） was 10.62%, significantly lower than that of TP-4 （19.44%） or D minghui63 （23.14%）, and it was close to the level of diploid control （7.30%）. In telophase I （TI）, maintainer D46B exhibited a lower frequency of microkemel, and in telophaselI （TII） the frequency of normal quartered microspore of maintainer D46B was not only higher than that of TP-4 or D minghui63 but also than that of diploid control. The percentage of the cell observed chromosome lagging in A1 and the percentage of abnormal cell in TI showed a greatly significant positive correlation. That may demonstrate chromo some separation in anaphase I （AI） and microkemel formation in telophase I （TI） are controlled by the same dominant single gene or the major gene of QTL.