Effect of Tuber Size and GA3 on the Growth and Stimulation of Flowering of Zantedeschia pentlandii cv. Picasso

Zantedeschia, native to southern Africa, herbaceous flowering plants in the family Araceae, with common names such as Arum lily, Trumpet lily, Pig lily, or Miniature Calla Lily. Calla lilies are among the most colorful flowers with a unique flower form. It is one of the most important pot, cut flower and outdoor plant in the world. GA3 is sometimes used to stimulate growth and flowering of plants. The aim of this study was to investigate the effects of GA3 and different weights of rhizome on growth, development, as well as qualitative and quantitative properties, of Zantedeschia in the greenhouse.

This research was carried out to evaluate the effect of different concentrations of GA3 on micro-tuber of Z. pentlandii cv. Picasso. Micro-tuber in three sizes and average weights included; large (S1=6.20g), medium (S2=3.20g) and fine (S3=1.20g) soaked in GA3 solution with concentrations 0, 250, 500, 750 ppm for 30 minutes. Experiments were carried out in a factorial arrangement with randomized complete block design with three replications. 10 micro-tuber cultured in bed with compounds of 60% coco peat and 40% perlite in greenhouse conditions. From the time of planting to harvesting, the ability of micro-tuber sprouting, leaf length, leaf width, stem length, number of flowering stems, plant height, flower diameter (spathe), number of buds, bud length, the diameter and weight of the micro-tuber after harvest were evaluated.

The results showed that the maximum length of leaf (100% more than S3GA0) length of flowering stem, diameter and length of flower (spathe) were observed in S1 tubers treated with 500 ppm (S1GA500) and the least amount was obtained in control treatment (S3GA0). The fastest germination was in S1 tubers with 750 ppm (S1GA750 36% earlier than S3GA0) and the earliest flowering was in S2 tubers with 500 ppm treated (S2GA500) which have flowering 28% earlier than S3 tubers with 250 ppm (S1GA250) but non-GA treated tubers in all three sizes have none flower. The highest weight and diameter tuber belonged to S1 tubers with 500 ppm and the lowest weight in S3 tubers without treatment. S3 tubers did not enter the flowering stage. It was shown that the GA3 treatment on Zantedeschia ‘Picasso’ tubers caused earlier flowering and the formation of a greater number of flowers and leaves. GA3 decreased the time between germination and appearance of flower. In simple effects study, large tubers (S1) and GA500 treatment were superior to other treatments in almost all traits. Also, the method of soaking of tubers with GA3 can be used in production scheduling, early efficiency and selection of superior populations in breeding programs.

The best growth and flowering indices were S1 tubers with treatment of 500 ppm. S1 tubers with GA3 (500 ppm) treatment were superior in all traits to other treatments. The method of soaking of calla tubers with GA3 can be used in production, increasing efficiency and selecting superior populations in breeding programs.