Early inbreeding depression and pollen competition in Calluna vulgaris (L.) Hull.

Citation
G. Mahy et Al. Jacquemart, Early inbreeding depression and pollen competition in Calluna vulgaris (L.) Hull., ANN BOTANY, 83(6), 1999, pp. 697-704
Citations number
33
Categorie Soggetti
Plant Sciences
Journal title
ANNALS OF BOTANY
ISSN journal
03057364 → ACNP
Volume
83
Issue
6
Year of publication
1999
Pages
697 - 704
Database
ISI
SICI code
0305-7364(199906)83:6<697:EIDAPC>2.0.ZU;2-1
Abstract
We investigated whether partial self-sterility in Calluna vulgaris results from abortion of selfed offspring owing to inbreeding depression or a late- acting self-incompatibility mechanism, and whether self-pollen interferes w ith normal functioning of cross-pollen. Self-pollination resulted in 75% le ss seed set than cross-pollination. Self-pollen tubes reached ovaries and p enetrated ovules as often as those of cross-pollen. Following self-pollinat ion, examination of the size of undeveloped seeds showed that at least 70% resulted from ovule fertilization and arrest of development occurred at var ious stages. All self-pollinated plants produced seeds and self-fertility v aried among plants. These results indicate that the reduced seed set observ ed in self-pollination is more likely the result of inbreeding depression r ather than a late-acting self-incompatibility system. The fecundity compone nt of inbreeding depression was high (0.762). Seed set was reduced by an av erage of 40% when self-pollen was mixed with cross-pollen, compared to pure cross-pollination. Using genetic markers, we found about 20% of seeds resu lted from self-pollination in mixed pollinated fruits. C. vulgaris is likel y to experience self-pollination in nature and our data suggest this will r educe the number of ovules that might otherwise mature after cross-pollinat ion. (C) 1999 Annals of Botany Company.