Meiotic behaviour in three interspecific three-way hybrids between Brachiaria ruziziensis and B. brizantha (Poaceae: Paniceae)

Journal of genetics

Maria Suely Pagliarini1¹  Eleniza De Victor Adamowski¹  Cacilda Borges Do Valle² 

[1] Department of Cell Biology and Genetics, State University of Maringá, 87020-900 Maringá PR, Brazil$$;Embrapa Beef Cattle, P.O. Box 154, 79002-970 Campo Grande MS, Brazil$$

关键词: B. brizantha;    B. ruziziensis;    three-way hybrids;    genome affinity;    meiotic abnormalities;    forage grass.;   

DOI  :  

学科分类：生物科学（综合）

来源: Indian Academy of Sciences

【 摘 要 】

The meiotic behaviour of three three-way interspecific promising hybrids (H17, H27, and H34) was evaluated. These hybrids resulted from the crosses between B. ruziziensis × B. brizantha and crossed to another B. brizantha. Two half-sib hybrids (H27 and H34) presented an aneuploid chromosome number ($2n = 4x = 33$), whereas hybrid H17 was a tetraploid ($2n = 4x = 36$), as expected. Chromosome paired predominantly as multivalents suggesting that genetic recombination and introgression of specific target genes from B. brizantha into B. ruziziensis can be expected. Arrangement of parental genomes in distinct metaphase plates was observed in H27 and H34, which have different male genitors. Hybrids H17 and H34 have the same male genitor, but did not display this abnormality. In H17, abnormalities were more frequent from anaphase II, when many laggard chromosomes appeared, suggesting that each genome presented a different genetic control for meiotic phase timing. Despite the phylogenetic proximity among these two species, these three hybrids presented a high frequency of meiotic abnormalities, mainly those related to irregular chromosome segregation typical of polyploids, H34, 69.1%; H27, 56.1% and H17, 44.9%. From the accumulated results obtained through cytological studies in Brachiaria hybrids, it is evident that cytogenetical analysis is of prime importance in determining which genotypes can continue in the process of cultivar development and which can be successfully used in the breeding. Hybrids with high frequency of meiotic abnormalities can seriously compromise seed production, a key trait in assuring adoption of a new apomictic cultivar of Brachiaria for pasture formation.

【 授权许可】

Unknown