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The all year round cultivation of cut sunflower in San Remo District

Gimelli, F., Leporati, A., Maggiora, L.
Acta horticulturae 2003 no.614 pp. 553-560
Helianthus annuus, cultivars, daminozide, flowers, genotype, growth regulators, markets, photoperiod
The cultivation of cut sunflower is relatively new and continuously increasing on the market. While in the Dutch auctions this product plays an important role all year round, in our area the production period is concentrated in a few months (from April to November). For this reason, for two years, we sowed several cultivars 4 times a month each 10 days starting from September 10th. Another problem is obtaining plants with a reduced growth. We tested a number of levels of Alar (Daminozide 85 %) in different periods and also different amounts of sprayed solutions during the cycle. The results show a clear influence of different genotypes on the cultural cycle and on two morphological characters (diameter of flower heads, length of stem). The reduction of day length (< 12 hs) provokes the most marked elongation of the cultural cycle in Sundeep . The length of stem and the diameter of flower heads are reduced only in Sunrich Orange out of market from a commercial point of view in this period. A modulating effect of the quantity of the light has also been observed. A prolonged period with little light seems to reduce the length of stem and the diameter of flower heads. Growth regulator Daminozide influences the morphological characteristics of the tested cultivars but not the length of cultural cycle. The length of the stem is controlled but only at higher dosages (200 – 300 g/l) repeated 3 times. During the warm period, to obtain good results, it is necessary to increase the sprayed solutions by 50 %.