Meiotic behaviour and chromosome identification in the Portuguese cultivar of triticale ‘Douro’ using in situ hybridisation

A. Carvalho

Department of Genetics and Biotechnology, CGB/ICETA, University of Tras-os-Montes and Alto Douro, 5000-911 Vila Real, Portugal (Portugal)

H. Guedes-Pinto

Department of Genetics and Biotechnology, CGB/ICETA, University of Tras-os-Montes and Alto Douro, 5000-911 Vila Real, Portugal (Portugal)

J. S. Heslop-Harrison

Department of Biology, University of Leicester, Leicester LE1 7RH, United Kingdom (United Kingdom)

J. Lima-Brito

jbrito@utad.pt
Department of Genetics and Biotechnology, CGB/ICETA, University of Tras-os-Montes and Alto Douro, 5000-911 Vila Real, Portugal (Portugal)

Abstract

The wide hybridisation has been applied to cereals breeding allowing to the production of new amphiploids. Triticale (X Triticosecale Wittmack) was the first synthetic amphiploid of the Triticeae tribe and performed well in comparison with its parent’s wheat and rye. In this work we aimed to analyse the meiotic behaviour and to identify the chromosomes present in both mitotic and meiotic metaphase cells of the portuguese cultivar ‘Douro’ (2n=42, AABBRR) using in situ hybridisation technique with genomic DNA from rye and repetitive DNA sequences as probes. Triticale ‘Douro’ presented a high level of homologous pairing. The mean number of bivalents was 20.14 and the average of ring bivalents was higher than rod bivalents. The total frequency of univalents was reduced (1.72), presenting the wheat univalents a higher frequency comparatively to the rye univalents. No multivalent configurations were seen, confirming the high meiotic regularity and stability of triticale ‘Douro’. The simultaneous use of pSc119.2 and pSc250 repetitive DNA probes on mitotic and meiotic chromosomes allowed the identification of all rye chromosomes. The pSc119.2 probe identified some wheat chromosomes, namely from B genome, and the chromosome pairs 4A and 5A.

Keywords:

chromosome identification, in situ hybridisation, meiotic pairing, repetitive DNA clones, Secale cereale, triticale