Cytomorphological Behaviour and Origin of Aneuploids in Tetraploid Pearl Millet (Pennisetum americanum (L.) K. Schum)

Abstract

Aneuploids with 27- to 30-chromosomes were isolated in the progenies of induced tetraploids of pearl millet in a lower frequency in C2 generation. These aneuploids were apparently recovered through female transmission, which varied for aneuploid gametes with different chromosome numbers. Aneuploids could be distinguished from eu-tetraploids on a morphological basis. Cytological study showed that 27-chromosomes variant was characterized by a high frequency of univalents and their precocious splitting at AI followed by the formation of bivalents in addition to rare presence of trivalents and quadrivalents/cell. But bivalents were highly frequent in both hypertetraploids. Thus, a frequency of bivalent is suggestive of “preferential pairing”. Moreover, the induced bivalentization noted in both eu-and aneuploids of advanced generation tetraploids of pearl millet may be accounted to high selection pressure. © 1983, Japan Mendel Society, International Society of Cytology. All rights reserved.