Metaphase I centromere co-orientation in interchange heterozygotes of pearl millet

Using interchanges T(1, 3) and T(3, 6) of Pennisetum americanum orientation types of the interchange multiple at MI were studied in different genetic backgrounds. Orientation types alternate 1 and alternate 2, in addition to adjacent 1, adjacent 2 and indefinite could be identified for both the interchanges. The relative frequencies of various orientation types were influenced by a change in the genetic background. For these interchanges, homologous centromeres do not seem to play a predominant role in the co-orientation of interchange multiple. The non-homologous co-orientation types were more subjected to genetic regulation than the homologous co-orientations.