Flowering period is independent from successful reproduction in Erica gracilis L.

Abstract

Erica gracilis is an important bedding plant in Northern Europe. Due to self-incompatibility, the development of new varieties was largely based on mutant selection from the predominant variety ’Glasers Rote‘. By crossing ’Glasers Rote‘ with wild types from South Africa in the 1980th, new cross-based varieties arose. Since the cultivation of cross-based varieties, precocious floral withering has been observed more frequently in production areas, suggesting that successful fertilization through open-pollination induces early floral senescence. A cluster analysis of current varieties based on AFLP markers confirmed the close relationship of old varieties and showed the expanded genetic diversity of cross-based varieties. Cross-experiments revealed that both, crosses of ’Glasers Rote‘-based genotypes with new cross-based genotypes and crosses between new genotypes, were successful. In contrast, selfings as well as crosses between old genotypes failed to produce seeds due to inhibition of pollen tube growth. Interestingly, we detected one self-compatible genotype, which provides new possibilities for breeding. No significant effect of open-pollination on the flowering period was observed by studying 16 genotypes, including old and new ones. This circumstance allows the mixed cultivation of different varieties in one production area. However, the flowering period was significantly affected by genotype and environment, suggesting that environmentally adapted varieties with long flowering periods can be bred.