Molecular Cytogenetic Characterization of the Native Forage Grass Trichloris crinita

NOVO, P. E.; KOZUB, C.; CAVAGNARO, P. F.; LAS PENAS, L.

CROP SCIENCE

CROP SCIENCE SOC AMER

Lugar: Baltimore; Año: 2019 vol. 59 p. 1 - 13

0011-183X

Trichloris crinita is a perennial forage grass native to ?and of wide distribution in- arid and semi-arid regions of the American continent. Its forage value in these dry lands obeys, in addition to its good forage quality, to its high tolerance to drought, salinity, trampling and grazing. Genetic and cytogenetic information for T. crinita is very scarce, hindering progress in genetic research and breeding of the species. Chromosome numbers, karyotypes, heterochromatin distribution, physical mapping of rDNA genes (18-5.8-26S and 5S) by FISH, and chromosome pairing in meiotic cells were described, for the first time, in T. crinita accessions. Karyotype based on chromosome morphology and cytogenetic landmarks are presented for eight T. crinita accessions. Physical mapping of rDNA loci revealed variation in the number, size and intensity of the 18-5.8-26S FISH signals, whereas 5S rDNA produced two signals per accession. Considering a basic chromosome number of 10, as reported for most Chloridoideae species, the facts that all 20 T. crinita accessions analyzed had 40 somatic chromosomes, that only bivalent chromosome pairings were observed in meiosis, and that chromosome morphology and sizes revealed high similarity between pairs of chromosomes, along with other reproductive features of the species, strongly suggest that T. crinita is an allotetraploid (2n=4x=40). Our cytogenetic data represent a useful resource for advancing cytogenetic research and breeding in T. crinita.