Meiotic behavior in nonaploid accessions of Brachiaria humidicola (Poaceae) and implications for breeding.
Meiotic behavior in nonaploid accessions of Brachiaria humidicola (Poaceae) and implications for breeding.
Author(s): BOLDRINI, K. R.; ADAMOWSKI, E. V.; SILVA, N.; PAGLIARINI, M. S.; VALLE, C. B. do
Summary: 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. Chromosome pairing as bi- to nonavalent associations at diakinesis indicated a basic chromosome number in this species of x = 6, as found in other closely related Brachiaria species. Thus, these 27 accessions are nonaploid (2n = 9x = 54). Abnormalities were found in the meiosis of these accessions, at variable frequencies. The most common abnormalities were those related to irregular chromosome segregation, which led to unbalanced gamete formation; but chromosome stickiness, cell fusion, and absence of cytokinesis were also recorded. Although some accessions have a low frequency of meiotic abnormalities, ensuring potentially good pollen viability, these cannot be used in hybridization due to a lack of sexual accessions with the same ploidy level.
Publication year: 2011
Types of publication: Journal article
Unit: Embrapa Beef Cattle
Observation
Some of Embrapa's publications are published as ePub files. To read them, use or download one of the following free software options to your computer or mobile device. Android: Google Play Books; IOS: iBooks; Windows and Linux: Calibre.
Access other publications
Access the Agricultural Research Database (BDPA) to consult Embrapa's full library collection and records.
Visit Embrapa Bookstore to purchase books and other publications sold by Embrapa.