四种栽培棉合成的四元杂种F_1细胞遗传学研究

Study on Cytological Characters of a Quadrispecific Hybrid F_1 from Four Cultivated Species in Gossypium

用(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。对四种栽培棉的四元杂种F1花粉母细胞减数分裂各时期染色体行为观察结果表明,四元杂种F1的减数分裂异常,染色体丢失现象普遍,部分染色体不能联会配对,以单价体的形式存在,并出现三价体、四价体、五价体等多价体,在减数分裂的末期形成大量的不正常多分孢子,导致四元杂种F1高度不育。然而,四元杂种F1减数分裂中大多染色体仍能配对,形成环状或棒状二价体,并有较多的三价体、四价体、五价体等多价体,表明四种栽培棉种之间的亲缘关系相对较近,可以通过遗传重组产生综合四个栽培棉种性状的新种质。

The quadrispecific hybrid F1 (G.arboreum, G.herbaccum, G.hirsutum and G.barbadense) was produced by crossing the doubled (G.arboreum×G.herbaccum) F1 with (G.hirsutum×G.barbadense) F1. The characteristic of chromosome behavior during the meiosis in the quardispecific hybrid F1 was studied. The results showed that the meiosis of the quardrispecific hybrid F1 was abnormal, and some of the chromosomes were lost in most PMC. Most of the chromosomes could not pair into bivalents, many univalents were found, and a few multivalents were found occasionally in PMC during the meiosis MI. Many abnormal Multispores were also formed in the telophase II, which may be the most important reason for the sterility of quardrispefic hybrid F1. However, most of the chromosomes of the quardrispecific hybrid F1 still paired into bivalents, or even trivalents, quadrivalents, quinquevalents and so on, which showed that the relationship of four cultivated cottons is relatively closed, and it is possible to produce a new germplasm with good characters of four cultivated cottons through genetic recombination.