二倍体棉种间杂种F_1的形态和细胞学

Cytology and Morphology of F_1 Hybrids Among Some Diploid Gossypium Species

研究了中棉(Gossypium arboreum race sinense)×长须棉(G.barbosanum Phillips ＆ Clement)、草棉(G.herbaceum race kuljianum)×长须棉、草棉×异常棉(G·anomalum Wawra ＆ Peyr)、草棉×司笃克氏棉(G.stocksii Master in Hooker)四个种间杂种F_1的一些形态性状的遗传变异及花粉母细胞减数分裂的染色体行为.四个种间杂种一代,有的性状表现双亲类型,有的则表现超亲.减数分裂中期Ⅰ的染色体构型各不相同,依次分别为:2.18 Ⅰ+11.06 Ⅱ+0.032 Ⅲ +0.37 Ⅳ+0.008 Ⅵ+0.008 Ⅶ;3.63Ⅰ+11.17 Ⅱ+0.01 Ⅳ;3.07+11.42 Ⅱ+0.027 Ⅲ和15.56Ⅰ+5.21Ⅱ+ 0.01 Ⅲ.这一结果表明,草棉与长须棉、异常棉的亲缘关系比较近,与司笃克氏棉的亲缘关系较远;而中棉与长须棉之间存在染色体易位等结构变异.由此推断,草棉比中棉更接近B染色体组棉种,可能草棉由B组棉种进化而来,然后由草棉经过染色体结构变异,进化产生了中棉.试验中还发现在减数分裂四分体形成时期存在多分孢子等现象.

The F1 generation of four interspecific hybrids in Gossypium,G. arboreum race sinense (2n = 26, A2) X G. barbosanum Phillips & Clement (2n = 26,B3), G. herbaceum race kuljianum (2n = 26,A1) X G. barbosanum,G. anomalum Wawra & Peyr (2n = 26,B1) and G. stocksii Masters in Hooker (2n = 26, E1) , were observed for their chromosome behavior in meiosis of pollen mother cells and the inheritance of some morphological characters. The F1 hybrids showed obvious transgressive inheritance and most of their characters were intermediate between their parents. They differed from each other in chromosome configuration at metaphase Ⅰ ,with 2. 18 Ⅰ + 11. 06 Ⅱ + 0. 032 Ⅲ + 0. 37 Ⅳ + 0. 008 Ⅵ + 0. 008 Ⅶ in G.arboreum × G. barbosanum , 3. 63 Ⅰ + 11. 17 Ⅱ + 0. 01 Ⅳ in G. herbaceum × barbosanum ,3. 07 Ⅰ +11.42 Ⅱ + 0.027 Ⅲ in G. herbaceum × G. anomalum and 15.16 Ⅰ + 5. 21 Ⅱ + 0. 01 Ⅲ in G. herbaceum × G. stocksii . The results indicated that G. herbaceum was more closely related to G. barbosanum and G. anomalum than to G. stocksii . Chromosome structural changes such as translocations Were found between G. arboreum and G. barbosanum . It is concluded that G. herbaceum was evoluted from B genome species and then evoluted into G. arboreum . Aneuspory ap-peared frequently during the tetrad formation in PMC meiosis of F1 hybrids. The evolutionary relation-ships among the four species and the use of their interspecific hybrids are discussed.