Related GMR Articles
Microsporogenesis was analyzed in five accessions of Brachiaria dictyoneura presenting x = 6 as the basic chromosome number. All accessions were tetraploid (2n = 4x = 24) with chromosome pairing in bi-, tri-, and quadrivalents. The recorded meiotic abnormalities were those typical of polyploids, including precocious chromosome migration to the poles, laggard chromosomes, and ... more
In the hexaploid (2n = 6x = 54) accession B176 of Brachiaria brizantha, one cytological characteristic differentiated it from the other accessions previously analyzed with the same ploidy level. Nearly 40% of meiocytes displayed the chromosome set arranged at two metaphase plates at the poles of the cell, close to the membrane. In these cells, both metaphase plates were ... more
The genus Brachiaria comprises more than 100 species and is the single most important genus of forage grass in the tropics. Brachiaria brizantha, widely used in Brazilian pastures for beef and dairy production, is native to tropical Africa. As a subsidy to the breeding program underway in Brazil, cytological studies were employed to determine the chromosome number and to ... more
Brachiaria humidicola (Poaceae), originally from Africa, is an economically important pasture plant in tropical South America. An accession of B. humidicola (H038) collected from the wild African savanna (Mbeya, Tanzania) showed irregular microsporogenesis. This meiotic behavior was consistent with an allopolyploid origin. Multivalent chromosome association at diakinesis ... more
Three sexual interspecific hybrids of Brachiaria (HBGC076, HBGC009, and HBGC014) resulting from crosses between B. ruziziensis (female genitor) and B. decumbens and B. brizantha (male genitors) produced by Embrapa Beef Cattle in the 1980s were cytologically analyzed by conventional methods for meiotic studies. The cytogenetic analysis showed the ... more
Analysis of DNA polymorphisms allows for the genetic identification and precise discrimination of species with a narrow genetic base such as common bean. The primary objectives of the present study were to molecularly characterize commercial common bean varieties developed at various research institutions using microsatellite markers and to determine the degree of genetic diversity among ... more
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 ... more
Estimating the performance of a rice breeding program is possible by means of indexes such as the replacement rate, which quantifies the dynamism of the breeding program and provides the rate of included, excluded, maintained and renewed genotypes year after year. We evaluated the performance of the irrigated rice breeding program in the state of Minas Gerais, ... more
Rice (Oryza sativa) is crop that adapts well to diverse soil and climate conditions; breeding programs have generally been committed to identifying and selecting genotypes that are stable and have high productivity in various environments. In this sense, studies of adaptability and stability are of paramount importance to aid in the recommendation of ... more
Endogamy places genes for several characteristics in homozygosis, which include those related to meiosis causing abnormalities that may impair gamete viability. An original population (S0) of popcorn (CMS-43) produced by Embrapa Maize and Sorghum was self-pollinated for seven years, generating inbred lines (S1 to S7). Conventional studies of microsporogenesis revealed ... more