モロコシ属の亜節間雑種の細胞遺伝学

Abstract

The dominant-recessive relationship between the foctor pairs has been determined in respect to the various quantitative characters in the two interspecific hybrids, within the genus Sorghum, between non-rhizomatous subsect. Arundinacea and rhizomatous subsect. Halepensia species, S. propinquum.Microsporogenesis has been studied both in the parental species as well as in the F1 hybrids between them laying emphasis on the nature of chromosome pairing at mid-pachytene stage and chiasma frequency at later stages. The nature of chromosome pairing, particularly at mid-pachytene stage in these two inter-subsectional hybrids, has indeed been very useful in providing considerable information bearing on the presence or absence of structural changes between the chromosomes of these species. Some of these structural changes have been considered to play a role to restrict the homology between chromosome complements of these species, thereby providing an effective mechanism in genetic differentiation. Based on cytomorphological data, it has been shown that the diversification in these parental species has gone at the structural as well as morphological levels. Therefore lumping of S. propinquum into the subsect. Arundinacea as one 'super-species' is not considered practical.