Meiotic observations on pollen mother cells of sexual progenies of citrus somatic hybrid
GAO Juan,YI Hua-lin,HU Zhi-yong (National Key Laboratory on Crop Genetic Improvement,The National Breeding Center on Citrus,Huazhong Agricultural University,Wuhan,Hubei 430070 China)
The sexual progenies of citrus somatic hybrid possess three parents' genetic materials. In order to investigate their cytological behavior,the sexual progenies of a cross between allotetraploid hybrid [Hamlin sweet orange(Citrus sinensis Os-back)+Rough Lemon(C. jambhiri Luss)] (as the pollen parent) and mono-embryonic diploid type Iben No. 4 [Huanongben-dizao tangerine (C. reticulata Blanco)×Ichang papeda (C. ichangensis Swingle)] was used as materials for observing the meiotic course of their pollen mother cells. The results showed that the PMC of diploid progenies showed normal meiosis,while a series of abnormal meiotic phenomena were observed in triploid progenies,such as univalent(56.9%)and multi-valent,one to three chromosomes beside the equatorial plate at metaphaseⅠ(51.2%)or metaphaseⅡ(38.7%). Chromosome bridges,chromosomes fragment,lagging chromosomes at anaphaseⅠor anaphaseⅡ and the small nucleus in tetrads were also frequently observed. Meanwhile,the relationship between the meiotic stage and diameter of floar bud was analyzed.