EFFECTS OF ENVIRONMENTAL CONDITIONS ON FLOWER INITIATION AND DEVELOPMENT OF ALLIUM SPHAEROCEPHALON L.

J. Berghoef, A.P. Zevenbergen
Flower initiation of Allium sphaerocephalon is not taking place during dry storage of the bulbs at temperatures ranging from 2–21°C. Storage for a minimum of 8 weeks at 2–13°C accelerates flowering after planting irrespective of growth conditions. Planting the bulbs in autumn requires a low temperature of 9–13°C and a daylength of 16–24 hours for flower initiation. Higher temperatures and/or a daylength of 8 hours keep the plants in the vegetative stage, the apex continues to initiate leaves.

Elongation of the inflorescence stalk is enhanced by increasing the temperature to 17–20°C after the inflorescence has become visible outside the leaf sheath. A long day of 16 hours at that time accelerates flowering and improves inflorescence quality by increasing the size.

Bulbs can be stored at 0.5°C until early July giving an acceptable percentage of flowering plants, provided that it is preceded by a storage for 12 weeks at 20–23°C.

The flowering period of Allium sphaerocephalon can be extended from April till September with a high percentage of flowering plants and reasonable flower quality. For further improvement of inflorescence quality research for optimization of growth conditions is required.

Berghoef, J. and Zevenbergen, A.P. (1992). EFFECTS OF ENVIRONMENTAL CONDITIONS ON FLOWER INITIATION AND DEVELOPMENT OF ALLIUM SPHAEROCEPHALON L.. Acta Hortic. 325, 91-96
DOI: 10.17660/ActaHortic.1992.325.9
https://doi.org/10.17660/ActaHortic.1992.325.9

Acta Horticulturae