Productive Response to Gibberellic Acid in Three Cultivars of Seed Propagated Artichoke

Abstract

The usual artichoke productive cycle in The Spanish Mediterranean Coast with common clone varieties happens from October to May, but the most interesting period is from middle October to first March. Plants of three seed propagated cultivars('Imperial Star', 'Harmony' and 'Madrigal'), which were planted on 1st August 2005; were sprayed three times between 20th September and 20th October 2005 with gibberellic acid (GA(3)), at doses of 30, 60 and 90 mg L-1 (D-1, D-2 and D-3 respectively); so that it was applied a total of 375 L. ha(-1). Three replicates of 10 plants per cultivar were arranged in a completely randomized design. The highest early yields (until the end of January 2006) were obtained with all GA(3) doses compared to the control, and with 'Imperial Star' and 'Harmony' against ` Madrigal'. GA(3) doses did not affect early production of ` Imperial Star'. Nevertheless in 'Harmony' and mainly in ` Madrigal', the higher doses caused earlier productions, having been found significant interactions (GA(3) doses x cultivar). The total commercial yield (until the end of May 2006) was higher on control plants and D-1 and D-2 treated plants, than on D-3 plants. The total commercial yield was also higher in ` Madrigal' than in 'Harmony' and ` Imperial Star'. Besides, in ` Imperial Star' and 'Harmony' the total commercial yields decreased as GA(3) doses were increased. Head weight in the early and total commercial production was similar among cultivars and was not affected by the GA(3) dose. On the other hand the incidence of open bracts in the early production was higher on D-2 and D-3 treated plants, and this incidence was higher in ` Imperial Star' than in 'Harmony' and ` Madrigal' along all the experiment with statistically differences.