Meiotic behavior in nonaploid accessions of Brachiaria humidicola (Poaceae) and implications for breeding.

Brachiaria humidicola is a grass adapted to seasonally swampy grasslands in Africa; two cultivars, 'common' and Llanero, are widely used in Brazilian pastures. New cultivars are in great demand in order to diversify current production systems to achieve improved quality and yield. Cytological analyses of 55 accessions of this species available from the Embrapa Beef Cattle germplasm collection revealed that 27 are apomictic and have 2n = 54 chromosomes.

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

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 X B.

Abnormal cytokinesis in microsporogenesis of Brachiaria humidicola (Poaceae: Paniceae).

Microsporogenesis was evaluated in the Brachiaria humidicola collection of the Embrapa Beef Cattle Center, represented by 60 accessions. One accession (H121) presented an abnormal pattern of cytokinesis that had never been reported in this genus. Among 900 meiocytes analyzed in the first division, 10.

Cytogenetic characterization of Brazilian Paspalum accessions.

Chromosome number, pairing relationship and meiotic behavior were evaluated in 24 Brazilian accessions of different Paspalum species as an initial screening to determine which of them might be useful in an interspecific hybridization program. The analysis showed that six were diploids, 16 tetraploids and two hexaploids. The pairing relationship was typical for the ploidy level and agreed with reported data.