Factors affecting variation in outcrossing rate in Eucalyptus globulus
B. Patterson, R. Vaillancourt, D. Pilbeam
2004
Citations
55
Citations
Journal
Australian Journal of Botany
Full text
Semantic Scholar
Key Takeaway Key Takeaway: High self-incompatibility and upper canopy position in Eucalyptus globulus trees significantly increase outcrossing rates, while flowering time and abundance of flowers have less consistent effects.
Abstract
The mating system of the animal-pollinated forest tree species Eucalyptus globulus Labill. was investigated in a clonal seed orchard to determine the importance of self-incompatibility, floral timing, floral abundance and canopy position on explaining variation in outcrossing rates. Outcrossing rates were highly and significantly correlated with the degree of self-incompatibility of individual genotypes (R2 = 0.92). Outcrossing rates were also significantly higher in the upper than in the lower parts of tree canopies (0.78 ± 0.1 and 0.54 ± 0.1, respectively). In contrast, neither flowering time nor abundance of flowers on individual trees revealed consistent effects upon outcrossing rates, suggesting that these factors are either less important or inherently more unpredictable because their effects partly depend on complex interactions with animal pollinators. Screening seed orchards in order to identify trees with high self-incompatibility and restricting seed collection to these trees will ensure that a high proportion of the seed used for plantations is derived from outcrossing, thereby minimising the deleterious effects of inbreeding depression.