Asynapsis and spontaneous centromeric breakage in an inbred line of Pennisetum americanum (L.) Leeke

In one of the plants of the inbred line IP 1475 of Pennisetum americanum (L.) Leeke, spontaneous chromosome breakage was observed. Distribution of the breaks was non-random and was confined to the centromeres and to the chromosome ends. Breakage in the centric region was twice as frequent as that in the end segments. Further, nucleolar chromosomes were involved less frequently than others in breakage and stickiness. Other meiotic abnormalities like asynapsis, exaggeration and stretching of the centromere, chromosome stickiness and neocentric activity were also observed in the same plant. All these abnormalities were interpreted to be the features of breakdown of the genetic system resulting from the enforced inbreeding of the normally cross pollinated species.