The genomic composition of Tricepiro. A. synthetic forage crop

MARIA ROSA FERRARI, EDUARDO J. GREIZERSTEIN, HÈCTOR A. PACCAPELO, CARLOS A. NARANJO, ANGELINES CUADRADO, NICOLÀS JOUVE, LIDIA POGGIO

GENOME

Lugar: Canadà; Año: 2005 vol. 48 p. 154 - 159

0831-2796

Abstract: Chromosome in situ hybridization (FISH and GISH) is a powerful tool for determining the chromosomal location  of specific sequences and for analysing genome organization and evolution. Tricepiro (2n = 6x = 42) is a synthetic  cereal obtained by G. Covas in Argentina (1972), which crosses hexaploid triticale (2n = 6x = 42) and octoploid  Trigopiro (2n = 8x = 56). Several years of breeding produced a forage crop with valuable characteristics from Secale, Triticum, and Thinopyrum. The aim of this work is to analyse the real genomic constitution of this important synthetic  crop. In situ hybridization using total DNA of Secale, Triticum, and Thinopyrum as a probe (GISH) labelled with biotin  and (or) digoxigenin showed that tricepiro is composed of 14 rye chromosomes and 28 wheat chromosomes. Small  zones of introgression of Thinopyrum on wheat chromosomes were detected. The FISH using the rye repetitive DNA  probe pSc 119.2 labelled with biotin let us characterize the seven pairs of rye chromosomes. Moreover, several wheat  chromosomes belonging to A and B genomes were distinguished. Therefore, tricepiro is a synthetic hexaploid (2n= 6x = 42) being AABBRR in its genomic composition, with zones of introgression of Thinopyrum in the A genome of wheat. Key words: tricepiro, trihybrid, Triticum, Secale, Thinopyrum, in situ hybridization, FISH, GISH, genomic composition,  synthetic forage crop.