New Zealand Journal of Botany abstracts
B00026Received 19 July 2000; accepted 14 August 2000
Sexual reproduction in field populations of the facultative apomict,
Hieracium pilosella
GARY J. HOULISTON*
HAZEL M. CHAPMAN+
Department of Plant and Microbial Sciences
University of Canterbury
Private Bag 4800
Christchurch 1, New Zealand
*Miss E. L. Hellaby Indigenous Grassland Research Fellow
+Author for correspondence.
Email: h.chapman@botn.canterbury.ac.nz
Abstract Hand pollination under New Zealand field conditions
of capitula from each of six populations of Hieracium pilosella
(maternal parent) with the closely related but morphologically distinct H.
aurantiacum produced F1 hybrids in every case. The frequency of F1 hybrid
offspring among the populations ranged from 0.2 to 21.6%. Involucral bract
characteristics, leaf shape, and petal colour were the most useful characters
for identifying hybrid progeny. Most F1 hybrids were able to set seed by
apomixis, but a sexual individual was also recovered. The discovery that both
tetraploid and pentaploid H. pilosella can reproduce sexually, following
artificial pollination under field conditions, in New Zealand has implications
for the bio-control of this species. Sexually reproducing plants are more
likely to evolve resistance to host-specific bio-control agents than are
apomicts. These results are part of a larger, ongoing research programme
investigating the role of the environment in the expression of apomixis.
Keywords Hieracium pilosella; H. aurantiacum;
apomixis; hybrids; weed ecology
New Zealand Journal of Botany, 2001, Vol. 39: 141-146
0028-825X/00/3901-0141 $7.00 (c) The Royal Society of New Zealand 2001
PDF file of entire paper: medium quality (509K); (scanned from paper original: notes about this process)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
