摘要
以棉属(Gossypium)的四个栽培种的种间杂种F_1植株为材料,观察花粉母细胞减数分裂的染色体行为和测定花粉萌发率。结果表明:在中期Ⅰ,二元杂种(亚洲棉×草棉)F_1出现一个四体环;(陆地棉×海岛棉)F_1通常联会成26个二价体。三元杂种[(亚洲棉×草棉)F_1×陆地棉]F_1,[(亚洲棉×草棉)F_1双二倍体×陆地棉)F_1和四元杂种[(陆地棉×海岛棉)F_1×(亚洲棉×草棉)F_1双二倍体]F_1分别出现11.7个、8.8个和8.4个单价体以及1.2个,5.6个和5.7个三价体。在后期Ⅰ,两个二元杂种F_1的染色体分离较规则,而三元和四元杂种F_1极不规则。在四分体形成时期,两个二元杂种F_1的异常四分体频率为18.3～20.2％,三元和四元杂种F_1高达71.2～74.7％。各杂种F_1及其亲本花粉萌发率测定表明:(亚洲棉×草棉)F_1花粉的萌发率为54.3％,表现半不育;(陆地棉×海岛棉)F_1为85.7％,与其双亲基本一致;而三元和四元杂种F_1的花粉萌发率极低,仅为7.1～12.4％,表现高度的不育。
Plants of interspecific F1 hybrids of four cultivated species in Gossypium were used to study their PMC meiotic chromosomal behavior and their pollen germination rate. Results showed that dispecific hybrid (arbor sum × herbaceum) F1 had a four-chromosome-ring, and ( hirsutum × barbadense) F1 usually had 26 bivalents at metaphase I. Trispecific hybrid ( ( ar-boreum × herbaceum) F1 × hirsutum] F1, [ (arboreum × herbaceum) F1 amphidiploid x hirsutum) F1 and quadrispecific hybrid C ( hirsutum x barbadense) F1 × (arboreum × herba-ceum)F1 amphidiploid] F1 had 11.7, 8.8, 8.4 univalents and 1.2, 5.6, 5.7 trivalents, respectively at metaphase I. Chromosomes of two dispecific F1 hybrids Segregated regularly, and those of tris-pecific and quadrispecific F1 hybrids segregated very irregularly at anaphase I. During tetrad forming stage, the percentage of abnormal tetrads of two dispecific F1 hybrids was 18.3-20.2%, while that of trispecific and quadrispecific F1 hybrids increased to 71.2-74.7%. Examination of pollen germination rate on hybrids find their parents showed that the germination rate of ( arboreum × herbaceum) F1 was 54.3 %, being semisterile; that of (hirsutum × barbadense ) F1 was 85.7%, being similar to both parents; and that of trispecific and quadrispecific F1 hybrids was very low, being only 7.1-12.4%. Conseqently, trispecific and qurdrispecific F1 hybrids were highly sterile.
关键词
棉花
杂种F1
减数分裂
染色体
G. herbaceum L.I G. arboreum L.
G. hirsutum L.
G. barbadense L.
interspecific hybrids
meiotic chromosomal behavior
pollen germination rate
