Effect of planting dates bulb sizes and shading levels on the growth and flowering of Iris hollandica [electronic resource].

Includes bibliographical references.

The present experiment was conducted at the Horticulture & Landscape Department, Agriculture College, Diyala University. Iraq. during 2011-2012. The objective of the experiment was to study the effects of five planting dates (1st Oct., 1st Nov. 1st Dec., 1st Jan., and 1st Feb.), three bulb sizes (5-6. 6-7 and 7-8 cm) and two levels of shading (0 and 50%) on the growth and flowering of Iris hollandica cv. Prof. Blaauw. The studied parameters included days for flowering, plant height. flower diameter, flowering stem diameter, flowering stem fresh weight, vase life and the fresh weight of bulbs and bulblets. Planting dates and bulb sizes showed significant differences in all the studied parameters. Shading resulted significant differences with all studied parameters except flowering stem diameter and vase life. The interaction between planting dates and shading had significant differences in all the studied parameters. while the interaction between bulb size and shading level had significant differences with flower diameter, flowering stem diameter and fresh weight of the new bulbs. The best characteristics were obtained by early planting (1st Oct. and 1st Nov.) of larger bulbs (7-8 cm) under 50% shade. Key words: bulb size, Iris hollandica cr. Prof. Blaauw, planting date, shading.

Summary in Arabic.

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