Abstract
A chromosome derived from Aegilops cylindrica (2n=4x=28, genomically CCDD) causes chromosome breakage in the gametes lacking the alien chromosome in a common wheat (Triticum aestivum, 2n=6x=42, AABBDD) cv. Chinese Spring. The Ae. cylindrica chromosome was studied by monosomic analysis and demonstrated to successfully substitute for chromosomes 2A, 2B, and 2D in the disomic condition. From its morphology and C-banding pattern, the Ae. cylindrica chromosome was assumed to have been originated from the C genome. Therefore, the present author proposed to designate this alien chromosome as 2C. During this study, a telosome of the long arm, an isochromosome of the long arm, and a deletion in the long arm of the Ae. cylindrica chromosome were obtained. Their abilities of inducing chromosome breakage suggested that a gene responsible for the chromosome breakage was located on the distal half of the long arm of the alien chromosome.
