Cytological investigation of Triticale

Abstract

A cytological investigation of 15 different 56-chromosome Triticale and 16 Triticale with 42 chromosomes was carried out. 4 were primary Triticale and 12 were secondary Triticale. Chromosome pairing was not disturbed; 21 and 28 bivalents were found in the hexaploids and octoploids, respectively. Meiotic irregularities were established, however, in all the Triticale studied; in octoploids the frequency of the irregularities was 22–88% and in hexaploids it was 12–87%. In metaphase and anaphase asynchronous separation of chromosomes was noted. Incompatibility between wheat and rye genomes and the inactivation of single loci of rye chromosomes are suggested as the main causes of the irregularities in meiosis. Mitotic disturbances were found in all the amphidiploids. The frequency of anomalies in mitosis was considerably lower than in meiosis: in octoploids they made up 5%–11% and in hexaploids 6.2%–15.2%. In all the amphidiploids studied chimera plants were found containing pollen mother cells with different chromosome numbers. The chromosome number in the aneuploid cells varied from 8–48 in hexaploids and from 8–62 in octoploids. Octoploid Triticale had 29.4%–72.9% aneuploid pollen mother cells, while hexaploid Triticale had 5-2%–55-7%.