NUCLEAR DNA CONTENT AND PLOIDY LEVEL IN APOMICTIC BUFFELGRASS GENOTYPES

Abstract

Buffelgrass [Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.] is a polyploid fodder grass that reproduces mostly via apomixis. The wide genomic and cytological diversity present in the species indicates that the active field collection at Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV) of the National Institute of Agricultural Technology (INTA) might contain individuals with different ploidy levels. This researche aimed to determine nuclear DNA content and ploidy level of introduced apomictic germplasm of buffelgrass. Cytological studies showed different ploidy levels in the germplasm. Genetic resources include tetraploid (2n = 4x = 36) and aneuploid (2n = 43 and 44) individuals. The 10 materials that exhibited 2C values ranging between 3.04 and 3.17 pg were tetraploid cytotypes. The values of the four aneuploid individuals with 43 chromosomes ranged between 3.83 and 3.86 pg, whereas aneuploid individual with 44 chromosomes had a 2C value of 3.94 pg. Number of chromosomes and nuclear DNA content were correlated. In addition, a model equation was obtained to estimate DNA ploidy value in buffelgrass genotypes.