ALLOCATION OF A GAMETOCIDAL CHROMOSOME OF AEGILOPS-CYLINDRICA TO WHEAT HOMOEOLOGOUS GROUP-2

A chromosome derived from Aegilops cylindrica (2n=4x=28, genomically C CDD) causes chromosome breakage in the gametes lacking the alien chrom osome in a common wheat (Triticum aestivum, 2n=6x=42, AABBDD) cv. Chin ese Spring. The Ae. cylindrica chromosome was studied by monosomic ana lysis 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 origi nated from the C genome. Therefore, the present author proposed to des ignate this alien chromosome as 2C. During this study, a telosome of t he long arm, an isochromosome of the long arm, and a deletion in the l ong arm of the Ae. cylindrica chromosome were obtained. Their abilitie s of inducing chromosome breakage suggested that a gene responsible fo r the chromosome breakage was located on the distal half of the long a rm of the alien chromosome.