ENVIRONMENTAL PHYSIOLOGY OF THE ONION: TOWARDS QUANTITATIVE MODELS FOR THE EFFECTS OF PHOTOPERIOD, TEMPERATURE AND IRRADIANCE ON BULBING, FLOWERING AND GROWTH

Features of the environmental control of bulbing in onions, and of flowering in long-day-plants are described and compared.
Methods for measuring the time of onion bulb initiation are critically discussed.
A model for the effects of photoperiod and temperature on the rate of bulb initiation is described, and predictions from the model are compared with field observations.
A modification of a previous model for the effects of temperature and photoperiod on inflorescence development is described and compared with field data.
Some recent models for the effects of temperature and irradiance on crop growth which are suitable for onions are outlined.
Interrelations between growth and the developmental processes of bulbing and flowering are reviewed, and it is suggested that models of the three processes run in parallel could add more precision to understanding such interactions.
The better insights into crop production practices and observations resulting from these advances in crop physiology are discussed.
Needs and possibilities for future research in the crop physiology of onions are outlined.

I International Symposium on Edible Alliaceae

J.L. Brewster

https://doi.org/10.17660/ActaHortic.1997.433.37