Daily Archives: 15th of July 2010

Phylogeny and diversification of Myrtaceae

Phylogeny and diversification of Myrtaceae

Myrtaceae

Fleshy fruits have evolved independently several times amongst Myrtaceae. Using a family-wide phylogeny, Biffin et al. (pp. 79–93) find that the parallel evolution of fleshy fruit was accompanied by a positive shift in diversification rates for the tribes Syzygieae and Myrteae, and that fleshy fruits may thus represent a ‘key innovation’ for evolution of rainforest Myrtaceae.

Regulation of tillering in sorghum: genotypic effects

Regulation of tillering in sorghum: genotypic effects

Regulation of tillering in sorghum: genotypic effects

Tillering is generally recognized as one of the most plastic traits affecting accumulation of biomass and ultimately grain yield in many field crops. Kim et al. (pp. 69–78) study five hybrids of Sorghum bicolor, derived from a common genetic background and with similar phenology and plant height but contrasting tillering. They find that genotypic differences in tillering are associated with differences in the carbon supply–demand balance within a plant, and the results provide avenues for phenotyping mapping of populations to identify genomic regions regulating tillering.

Regulation of tillering in sorghum: environmental effects

Regulation of tillering in sorghum: environmental effects

Regulation of tillering in sorghum: environmental effects

Tillering has a significant effect on canopy development, resource capture, crop growth, and grain yield in cereal crops. Kim et al. (pp. 57–67) conduct a series of field and laboratory experiments to determine the effects of radiation and temperature on tillering in Sorghum bicolor, and develop a supply–demand framework to model regulation of tillering as a consequence of internal competition for carbohydrates. This may provide the basis for dynamic simulation of tillering in crop growth models.

Reticulate evolution in Polystachya (Orchidaceae)

 

Reticulate evolution in Polystachya (Orchidaceae)
Polystachya (Orchidaceae)

Evolutionary studies are usually based on dichotomously branching phylogenetic trees. Russell et al. (pp. 37–56) use DNA data from several plastid and low-copy nuclear genes to generate phylogenetic networks of Polystachya, showing reticulate evolution. One group of allotetraploid species has a recent history of long-distance dispersal and multiple hybrid origins; another shows considerable morphological diversity on Madagascar and the Comoros.