During the course of the present investigation artificially produced hybrids between the different morphological types of the
Dichanthium annulatuin complex and of
D. annulatum×
D. fecundum were analysed cytologically and morphologically so as to determine their inter-relationships.
Cytological analysis of the hybrids was made and the results compared with those of their respective parents. It was observed that the meiotic behaviour of the hybrids were similar or intermediate between their respective parents.
Morphological analysis revealed that the Tropical (2n=20, 40), Mediterranean (2n=40) and Senegal (2n=40) types are morphologically distinct races of
D. annulatum. In geographical distribution these races overlap, and are not genetically isolated. However, their morphological identity is maintained primarily through apomixis. These three ecotypic races of
D. annulatum may be grouped taxonomically under
D. annulatum var.
annulatum (2n=20, 40).
Dichanthium papillosum and
D. fecundum are isolated geographically but each overlap with
D. annulatum in their natural ranges of distribution. However, these two species are closely related to
D. annulatum and may be classified as
D. annulatum var.
papillosum (2n=60) and
D. annulatum var.
fecundum (2n=40) respectively. Furthermore,
D. annulatumn,
D. papillosum and
D. fecundum together, form one interrelated agamospecies, i.e., the
Dichanthium annulatum complex.
View full abstract