Summary:

The aim of the experiment was to evaluate the effects two irrigation regimes (soil suction -15 and -30 kPa) and different tuber weights on flower quality and tuber yield of Zantedeschia ‘Black Eyed Beauty' and ‘Treasure' grown in green-house during spring-summer season. Before planting tubers were sorted according to their initial weight to four groups: A (35 g), B (70 g), C (100 g) and D (150 g). Plant were grown in 3 or 5 L containers, groups A and B or C and D, respectively. After leaf unfolding plants were irrigated at two soil suction level: - 15 and - 30 kPa, according to "Watermark" sensors placed inside the containers. Irrigation significantly influenced growth and flowering of Zantedeschia. It was shown that irrigation at - 30 kPa delayed flowering time and decreased flower yield, especially in case of ‘Black Eyed Beauty'. Flowers had lower fresh weight and were shorter. The cultivar ‘Treasure' gave higher yield than ‘Black Eyed Beauty'.
Water stress negatively influenced tuber growth of both calla lily cultivars. The index of tuber growth strongly decreased with increasing the initial tuber weight at planting, however it was lower for plants irrigated at - 30 kPa. The results clearly showed the significance of optimal plant irrigation during Zantedeschia cultivation and the different cultivar response to this factor.