02509naa a2200253 a 450000100080000000500110000800800410001902400440006010000180010424501080012226000090023052017720023965000150201165000140202665000250204065000250206570000190209070000160210970000230212570000170214870000260216570000180219177300460220921403322022-02-23       2021    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1002/csc2.205422DOI1 aMORAES, I. C.  aKaryotype analysis and mode of reproduction of two species of Urochloa P. Beauv.h[electronic resource]  c2021  aGrasses with desirable traits for agriculture and livestock production are continuallybeing sought. The genusUrochloacomprises many species of good forage poten-tial, although studies have mostly focused on commercial cultivars. Karyotype datacan be used to characterize species and generate information for taxonomy and evo-lutionary studies and contribute to breeding programs. The mode of reproductionis also an essential piece of information to determine breeding strategies. This studyaimed to characterize the karyotypes ofUrochloa arrecta(Hack. ex T. Dur. & Schniz)O. Morrone & F. Zuloaga and a pentaploid cytotype ofU. brizantha(Hochst. exA. Rich.) R. Webster, including the mapping of ribosomal DNA (rDNA) sites andnuclear DNA content and indicating the mode of reproduction. Slides were pre-pared using the flame drying technique and were subjected to fluorescent in situhybridization with 35S and 5S rDNA probes. DNA content was estimated by flowcytometry. The classification of the reproduction mode was based on the amplifica-tion of the primers N14 and p779/p780.Urochloa arrectapresented 2C=2.66 pgof DNA, karyotype formula 2n=4x=34 m+2sm, four chromosomes with 35SrDNA sites, and four other chromosomes with 5S rDNA sites. The absence of ampli-fication products with the primers N14 and p779/p780 provided evidence of sexualreproduction.Urochloa brizanthapresented 2C=4.52 pg of DNA and karyotypeformula 2n=5x=45 m. Five chromosomes presented 35S rDNA, and eight otherchromosomes displayed 5S rDNA sites. Polymerase chain reaction results indicatedthat this cytotype has an apomictic mode of reproduction. The organization of kary-otypes suggests an allopolyploid origin for both genotypes. Possible applications ofthe information found are discussed.  aCariótipo  aGramínea  aGramínea Forrageira  aReprodução Vegetal1 aPEREIRA, W. A.1 aNANI, T. F.1 aPAULA, C. M. P. de1 aROCHA, M. J.1 aSOUZA SOBRINHO, F. de1 aTECHIO, V. H.  tCrop Science.gv. 61, p. 3415-3424, 2021.