Abstract:

Somatic hybridization is an available way to create new germplasm and enrich breeding materials. Somatic hybridization between B. napus and D. sophia has been finished by the authors in 2005. Present research is to continue progeny studies of the somatic hybrids with the objective of carrying out desirable genes transfer from D. sophia to B. napus. Fertile progenies of the somatic hybrids between Brassica napus (2n=38) and Descurainia sophia (2n=38) selfed in three consecutive generations, resulting in F₂, F₃, and F₄ populations. The number of somatic chromosome, chromosome behavior and genetic components from D. sophia in these progenies were observed and analyzed by cytological and SSR analyse. The average number of chromosomes in F₂, F₃, and F₄ populations were 38.47±3.17, 37.65±3.23, and 36.66±2.95, respectively, and the maximum number was 56, 50, and 45, respectively, showing that chromosome number tended to reduction with the generation progression. Abnormal chromosome behaviors such as chromosome bridges, lagging chromosomes, meiotic cycle asynchrony, chromosome unequal distribution at meiosis stage were often observed in the three populations. SSR marker detections with 22 pairs of primers showed that the average frequency of plants with bands characteristic of D. sophia in the F₂, F₃, and F₄ populations was 9.62%, 2.99%, and 0.31%, respectively. Therefore, achieving germplasm of D. sophia filter into B. napus should attach importance to select progenies of the somatic hybrid in F₂ population.

Key words: Brassica napus, Descurainia Sophia, Somatic hybrid, Chromosome behavior, SSR