Interaction between cultivar and gibberellic acid concentration in seed propagated artichoke

Abstract

Plants of three seed propagated artichoke cultivars (‘Harmony’, ‘Madrigal’ and ‘Nun-3033’), planted on 9th July 2004 at 0.74 plants m-2, were sprayed three times, every two weeks, with gibberellic acid (GA3) at 30, 60 and 90 mg L-1, starting on 17th September, applying a total of 375 L ha-1. Significant interactions between cultivar and GA3 concentration were found for early and total yields. Early yields of ‘Harmony’ reached the maximum at 60 mg L-1 of GA3, decreasing the response at higher concentration. Early yields of ‘Madrigal’ and ‘Nun-3033’ increased up to 90 mg L-1 of GA3. Early yields of ‘Madrigal’ were very low and not significantly affected by GA3 application at any concentration. There was no response by ‘Madrigal’, the latest among the three cultivars, at 30 mg L-1 of GA3, needing higher concentrations to achieve some early yields. Total yields proportionally decreased as GA3 concentration increased. In ‘Madrigal’ this reduction was less than proportional. In ‘Harmony’ and ‘Nun-3033’ total yields were higher in control than in GA3-treated plants, while in ‘Madrigal’ the highest yields were obtained in plants treated with 30 mg L-1 of GA3. Head weight in the early production was similar among the three cultivars and was not affected by the GA3 concentration, while average head weight at the end of the experiment was greater in ‘Madrigal’ than in the other cultivars.