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This paper reports the occurrence of chromosome elimination during microsporogenesis in an interspecific hybrid between a sexual diploid accession (SEX) of Brachiaria ruziziensis (2n=2x=18) and an apomictic tetraploid accession (APO) of B. brizantha (2n=4x=36). Meiosis was very abnormal in the triploid hybrid (2n=3x=27); we observed a distinct asynchrony(More)
Apomixis is widely distributed among tropical forage grasses, and has long been merely regarded as an impediment to breeding. Panicum maximum is presented as the first opportunity for Brazilian geneticists to develop and test original breeding schemes adapted to an apomictic species. A large and representative germplasm of P. maximum has been introduced and(More)
Guineagrass (Panicum maximum Jacq.) is a forage grass found in tropical and subtropical regions. It is an apomictic and tetraploid species from Africa. The objective of this study was to evaluate the genetic diversity of guineagrass accessions sampled from its regions of origin, which is in Tanzania and Kenya. In this study, a total of 396 accessions were(More)
Microsporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata (BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains were prepared by squashing and staining with 0.5% propionic carmine. The meiotic process(More)
Male meiosis is generally synchronous in higher plants. The regulation of the cell cycle is still not well understood, and a powerful tool for gaining an understanding of this regulation is the development of mutations that affect cell-cycle synchrony. We report here asynchronous microsporogenesis in an interspecific hybrid between two important tropical(More)
Guinea grass (Panicum maximum Jacq.) is a tropical African grass often used to feed beef cattle, which is an important economic activity in Brazil. Brazil is the leader in global meat exportation because of its exclusively pasture-raised bovine herds. Guinea grass also has potential uses in bioenergy production due to its elevated biomass generation through(More)
Microgametogenesis was analysed in an interspecific hybrid resulting from a cross between an artificially tetraploidized sexual accession of Brachiaria ruziziensis (2n = 4x = 36) and the apomictic cultivar (cv. Basilisk) of B. decumbens (2n = 4x = 36). Although each microspore initiated its differentiation by pollen mitosis, polarization of the nucleus was(More)
Centrosema pubescens Benth is a forage legume widespread in tropical America. Twenty-six polymorphic microsatellite markers were isolated and characterized in 15 genotypes of C. pubescens from the Cerrados Research Center Germplasm Bank of the Brazilian Agricultural Research Corporation (Embrapa). The number of alleles observed for each locus ranged from 2(More)
The objective of this study was to evaluate the genotypic stability of agronomic traits in hybrids of Panicum maximum. Hybrids originating from the crosses between two sexual parents and cultivars Mombasa and Tanzania were evaluated in an incomplete-block design. Evaluated traits were total dry matter, leaf dry matter, stem dry matter, percentage of leaves,(More)
In this study, we used microsatellite loci to estimate the outcrossing rate of Centrosema pubescens in open-pollinated populations of 10 progenies that each contained 20 genotypes. The multilocus outcrossing rate was 27%, which suggested a mixed mating system with a predominance of autogamy. The single locus outcrossing rate was 13%. The difference was(More)