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Identification of the double satellited chromosome
of hexaploid wheat variety Pb. C591 D. SINGH and B.C. JOSHI Division of Genetics, Indian Agricultural Research Institute, New Delhi, India BHADURI and NATARAJAN (1956) worked out the karyotype of the hexaploid wheat variety Pb. C591 and observed that it possessed (1) one long pair of satellited chromosomes, sub-medianly constricted and (2) two pairs of sub-medianly constricted medium sized chromosomes with satellites. The first pair of satellited chromosomes was found to be unique to this variety. This pair had a doubly constricted sat.-segments, i.e. there was a chromatic segment intervening the achromatic sat.-thread of the satellited chromosomes. This note reports the identification of this double constricted satellited chromosome. Root tip squashes of seeds derived from monosomic lines (2n=41) 1B, 6B and 5D of Pb. C591 were made and the somatic chromosome complement of the monosomic seed was studied. It was observed that in the aneuploid line 1B only one doubly constricted chromosome was present, whereas monosomic seeds of line 6B and 5D contained a pair of this chromosome. This chromosome is thus identified as 1B chromosome of the complement of Pb. C591. (Received July 8, 1969) |