活体保存对栽培棉种间四元杂种育性和染色体构型的影响

Effect of Plant Preservation on the Fertility and Chromosome Configuration of a Quadri-specific Hybrid Derived from 4 Cultivated Cotton Species

将(亚洲棉×草棉)F1进行染色体加倍,再与(陆地棉×海岛棉)F1进行杂交,产生亚洲棉、草棉、陆地棉和海岛棉四元杂种。对四元杂种F1进行15年的嫁接保存,对其花粉活力进行几年连续测定,并进行自交和回交。结果表明,四元杂种可育花粉率和弱生活力花粉率在逐年增加,不育花粉率逐年减少,其中弱生活力花粉增加到占10%以上,并能获得回交和自交种子。染色体组分析结果表明,四元杂种PMC减数分裂中期的染色体构型为2n=52=4.92Ⅰ+14.62Ⅱ+2.29Ⅲ+1.56Ⅳ+0.71Ⅴ+0.19Ⅵ,而15年前该四元杂种的染色体构型为2n=52=8.4Ⅰ+8.1Ⅱ+5.7Ⅲ+1.9Ⅳ+0.6Ⅴ。长期活体保存使四元杂种PMC减数分裂中期的每个细胞单价体数减少3.5个,二价体数增加6.5个,且多价体数也有明显减少。说明活体保存有利于协调染色体组之间的关系,使其染色体构型趋于协调和平衡,育性逐渐改善和恢复。

A quadri-specific hybrid F1（ G. a rboreum, G, herbaccum , G. hirsutum , and G. barbadense） were produced by crossing the chromosome doubled （G. arboreum×G. herbaccum） F1 with （G. hirsutum × G. barbadense） F1. The hybrid plants were preserved for 15 year via the method of grafting. The hybrid flowers were self-crossed and back crossed every year, and the pollen vigor was tested as well. The results showed that the percentage of fertile pollens and poor vigor pollens was increasing with the time of plant preservation,especially for those with of poor vigor that occupied about 10% of the total pollens after 15 years growth. Meanwhile, the percentage of the sterile pollens was decreasing with the plant preservation,and the fertility of the quadri-specific hybrid was recovered partially. After plant preservation for more than 10 years,some backcrossed seeds were obtained via backcrossing with the upland cotton parent,and a few self-crossed seeds were produced finally. The characteristics of chromosome behavior and the chromosome configuration during the meiosis were studied and the results showed that the chromosome configuration of the quadri-specific hybrid grown plant for 15 years was 2n=52=4.92 Ⅰ ＋ 14.62Ⅱ＋2.29Ⅲ ＋1.56 Ⅳ ＋0.71 V＋0.19Ⅵ, while the chromosome configuration from that plants 15 years ago was 2n=52=8.4 Ⅰ ＋8.1Ⅱ＋5. 7Ⅲ＋1.9Ⅳ＋0.6V. It was showed that the univalents were decreased about 3.5 per cell,bivalents were increased by 6.5 per cell,and the number of multivalents was decreased obviously as well. It was found from this experiment that extendedthe growth period by the method of grafting with cultivated plants would be helpful to harmonize the relationship among the different chromosome groups which came from different parents, and balance the chromosome configuration,which led to the partially recovering in plant fertility of the interspecific hybrids.