About this Research Topic
The timing and intensity of flowering directly determine the production of seeds and fruits. These traits are thus main targets in breeding programs focused on the increase of crop yield potential. In trees, these traits are related to phenological stages that repeatedly occur during their life cycle. In temperate climates, trees grow when the environmental conditions are permissive. Before the advent of winter they stop growing (growth cessation), their buds differentiate into either reproductive or vegetative meristems and acquired dormancy. During winter, the long exposure to cold induces the break of the bud dormancy. Subsequently, warm temperature in spring stimulates vegetative and floral bud burst. These phenology stages are highly influenced by environmental conditions, as for example ambient temperature and photoperiod. In terms of endogenous signals, the plant growth regulators, mainly the plant hormone gibberellin, and the carbohydrates play a major role in controlling flowering. The age of the plant is another relevant endogenous factor, as in many tree species flowering only occurs after an exceptionally long juvenile phase.
How these signals are integrated in genetics networks to control flowering occurrence and timing has been intensively studied in the annual model plant species Arabidopsis thaliana. However, there are specific biological questions that can only be addressed using tree species as models. For example, in many fruit trees, flower initiation can be strongly limited by an excessive crop, a phenomenon known as biennial (or alternate) bearing. Biennial bearing is therefore a decisive phenomenon for production in several tree species, as for example apple, pear, citrus, olive, mango, apricot and avocado. High quality genome sequence obtained for perennial tree species such as poplar and apple have recently opened new avenues to a deeper molecular characterization of the particular flowering phenology in trees. In addition, mathematical models able to capture the complexity of these processes have been developed. Altogether, these new tools are allowing a rapid progress towards an increased understanding of the control of flowering in trees. Moreover, in the context of the global climate change, this knowledge brings new breeding opportunities to obtain tree cultivars better adapted to the expected warmer temperatures.
In this Research Topic collection, we aim to gather articles covering the recent advances in genetic and molecular control of flowering phenology and modelling in trees. More specifically, we will pull together original and review papers focused on the following topics:
- Juvenility to adult phase change
- Floral induction and alternate bearing
- Bud dormancy and bud burst
- Modelling of tree growth and development
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.