The Cytology of Brachyscome Cass. (Asteraceae: Astereae). II. Hybridisation Between B. goniocarpa (N = 4) and B. dichromosomatica (N = 2)

Abstract

Artificial hybrids between the inbreeding species B. goniocarpa Sond. & F. Muell.(n = 4) and outbreeding B. dichromosomatica C. R. Carter var. dichromosomatica (n = 2) have been produced. Morphologically, the hybrids were essentially intermediate between the parental species. Cytological investigations showed that the total length of mitotic metaphase chromosomes for the B. dichromosomatica haploid set was 1.33 times that of the B. goniocarpa set. Chromosomes derived from the parental species showed similar condensation behaviour. Meiotic pairing involved both the B. dichromosomatica chromosomes and two of the four B. goniocarpa chromosomes; the other two B. goniocarpa chromosomes formed univalents. The results suggest that the current placement of the two taxa in different superspecies is not warranted.