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Nucleolus‐Organizing Accessory Chromosomes in Pearl Millet, Pennisetum typhoides 1
Author(s) -
Powell Jerrel B.,
Burton Glenn W.
Publication year - 1966
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1966.0011183x000600020008x
Subject(s) - biology , pennisetum , nucleolus , chromosome , meiosis , genetics , botany , gene , cytoplasm
Accessory chromosomes were discovered in an inbred line of pearl millet, Pennisetum typhoides (Burm.) Stapf and C.E. Hubb. The accessory chromosomes organized nucleoli which were independent of the A‐chromosome nucleolus in some microsporocytes and associated with the A‐chromosome nucleolus in others. Two A‐chromosomes in this inbred line associated with a single nucleolus in contrast to only one nucleolus‐organizing A‐chromosome commonly found in most pearl‐millet lines. Accessory chromosomes ranged from one to five within plants, and varied in number from plant to plant, head to head, spikelet to spikelet, and cell to cell. Small, intermediate, and large accessories were obesrved. Characteristic folding back on itself at diakinesis exhibited by the larger accessory suggested an isochromosome derived from the intermediate‐sized accessory. The number of accessories per cell appeared to have little effect on A‐chromosome pairing. Microsporocytes with the least amount of accessory‐chromosome association also had the least A‐chromosome pairing.