Journal Article

Early Inbreeding Depression and Pollen Competition inCalluna vulgaris(L.) Hull

JACQUEMART, ANNE-LAURE, MAHY, GRÉGORY

1999

Overview

We investigated whether partial self-sterility inCalluna vulgarisresults from abortion of selfed offspring owing to inbreeding depression or a late-acting self-incompatibility mechanism, and whether self-pollen interferes with normal functioning of cross-pollen. Self-pollination resulted in 75% less seed set than cross-pollination. Self-pollen tubes reached ovaries and penetrated ovules as often as those of cross-pollen. Following self-pollination, examination of the size of undeveloped seeds showed that at least 70% resulted from ovule fertilization and arrest of development occurred at various stages. All self-pollinated plants produced seeds and self-fertility varied among plants. These results indicate that the reduced seed set observed in self-pollination is more likely the result of inbreeding depression rather than a late-acting self-incompatibility system. The fecundity component of inbreeding depression was high (0.762). Seed set was reduced by an average of 40% when self-pollen was mixed with cross-pollen, compared to pure cross-pollination. Using genetic markers, we found about 20% of seeds resulted from self-pollination in mixed-pollinated fruits.C. vulgarisis likely to experience self-pollination in nature and our data suggest this will reduce the number of ovules that might otherwise mature after cross-pollination.

• Publisher: Elsevier Science Ltd,Oxford University Press,Oxford Publishing Limited (England)
• Subject: Botany / Calluna vulgaris(heather) / Calluna vulgaris(heather), self-pollination, pollen tube, ovule fertilization, early inbreeding depression, pollen interference / Cross-pollination / early inbreeding depression / Fecundity / Fertility / Genetic markers / Inbreeding / Offspring / ovule fertilization / Pollen / pollen interference / pollen tube / Pollination / Seeds / self-pollination