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Some notes on the origin of polyploidy in Hieracium pilosella aggr.
Author(s) -
Gadella TH. W. J.
Publication year - 1988
Publication title -
acta botanica neerlandica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0044-5983
DOI - 10.1111/j.1438-8677.1988.tb02158.x
Subject(s) - biology , hybrid , gamete , meristem , botany , chromosome number , somatic cell , protoplast , zygote , chromosome , genetics , gene , karyotype , shoot , embryogenesis , sperm
SUMMARY A cytological analysis of 1192 artificially produced hybrids in the collective apo‐amphimictic species complex, Hieracium pilosella/H. peleterianum , showed that 16 addition hybrids were formed; 15 of these were produced by the fusion of one reduced and one unreduced gamete and one by the fusion of two unreduced gametes. Zygotic chromosome doubling could be unambiguously ruled out. Polyspermaty and somatic doubling in meristematic tissue of the creeping stolons did not occur. The percentage (1.26%) of unreduced gametes is low but sufficient for the production of considerable numbers of addition hybrids, even in moderately large populations. The fact that addition hybrids are rare under natural conditions suggests that the adaptive value of these hybrids is inferior.