Hyrkas-Lyytikainen, K. 1984. Chromosomes and reproductive behaviour of Finnish Taraxacurn agamospecies. -Nord. J. Bot. 5: 127-141. Copenhagen. ISSN 0107-055X.Material consisting of 157 accessions of 69 Finnish Taraxacum agamospecies, representing 7 sections, was grown in an experimental field for comparison of certain botanical and nutritional characteristics. This paper gives the collecting data as well as cytological and reproductive characteristics of the material. The largest section Taruxacum (Vulgariu) was represented by 60 agamospecies, 59 of them triploid (2n = 24) and one tetraploid (T. penicilliforme, 2n = 32). The tetraploid and 37 triploids were chromosome counted for the first time. The diploid sexual species T. obtusilobum from Sweden was included for comparison. Other sections consisted of 3 triploids and 6 tetraploids, 3 tetraploid species of the section Erythrosperma being chromosome counted for the first time. Seedlings with deviating numbers were occasionally found. A banding technique of the chromosomes was developed but it did not allow the exact identification of other than the satellite chromosomes. Species-specific features were found in the flowering phenology and in several pollen characteristics (stainability, mean and variability of the size). There were indications of genetic variation within certain agamospecies in pollen characteristics. Isolated and emasculated (mostly only isolated) flower heads gave mostly a full seed set, which indicates obligate, autonomous agamospermy. Lower seed sets of T. adami, T. dahlstedtii and T. hamatiforme in isolation may be a sign of facultative apomixis in these species, requiring further study.
713 pollinations produced a total of 620 embryos, of which 34.4 % died on the culture medium. All the progenies attaining full growth proved to have resulted from self ‐pollination. Under greenhouse conditions only diploid red clover retained its strong self‐incompatibility: pollinations made on it produced no progenies. Nonetheless, the pollinated inflorescences produced as many globular embryos as did those of alsike or of the tetraploid clovers. These globular embryos, which died on the culture medium, were probably hybrids whose development was arrested at the globular stage by strong post‐fertilization crossing barriers between red and alsike clovers.
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