Rediscovery of a diploid cytotype of Dasypyrum breviaristatum in Morocco
2002
Ohta, S. | Koto, M. | Osada, T. | Matsuyama, A. | Furuta, Y.
The chromosome numbers of a total of 273 Dasypyrum breviaristatum plants sampled from 20 Moroccan and one Greek natural populations were examined. 270 plants from all of the populations were tetraploids. Among them, 223 were eu-tetraploids with 28 chromosomes and 47 were aneuploids with 25, 27 and 29 chromosomes. Besides, three plants were found to be diploids among 16 plants from a population in the Moyen Atlas Mountains of Morocco. This is the second report of a diploid cytotype of D. breviaristatum since the first communication in 1957. Morphologically, the diploids were similar to but smaller than the tetraploids in plant height, spike length, spikelet number and leaf epidermis cell size. However, it was not possible to distinguish between the two cytotypes based on those morphological characteristics alone. A distinct difference was found between the two cytotypes only in the number of trichomes on the leaf surfaces. The karyotype of the diploid cytotype consisted of a pair of SAT-chromosomes, five pairs of metacentric and a pair of submetacentric chromosomes. Based on the similarity in karyotype and in plant morphology between the two cytotypes of D. breviaristatum, we suggest that the diploid cytotype is the most probable candidate for the ancestral form of the tetraploid cytotype.
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