Changes in triticale chromosome heterochromatin visualized by C-banding

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Abstract
The distribution and characterization of heterochromatin in a series of cultivars, parents, new amphiploids and progeny of hexaploid triticale were comparatively studied using C-banding and morphometric analysis. A high level of intervarietal polymorphism was detected for the banding pattern. The chromosome pairs 4A and 1R presented the most constant pattern of heterochromatin distribution among 31 triticale lines studied. A total of 126 bands have been catalogued, from which 28, 59, and 39 belong, respectively, to the A, B and R genomes. The ratio of polymorphic bands per genome was 23/28, 36/59, and 30/39. The chromosomes displayed heterochromatin modifications consistent in both presence–absence and relative length of their content per genome, when passed from the parents to the amphiploids. Variations in the heterochromatin were also observed among sister plants coming from crosses between wheat and triticale. The heterochromatin content showed gradual tendencies either to increase or decrease in each genome during successive self-cross generations after that cross. The existence of a systematic process of variation of heterochromatin content in triticale is assumed, and the nature of this phenomenon is discussed.Key words: triticale, tetraploid wheat, rye, C-banding, heterochromatin.