Agronomic and Productive Response to Different Concentrations of Gibberellic Acid in Green and Purple Heads Artichoke Cultivars

Abstract

[EN] The production of seed propagated artichoke is considered one possible alternative to the vegetative propagation of green and purple artichoke heads. One drawback of using seed propagated artichokes is their late entry into production. In this study different gibberellic acid (GA3) concentrations, sprayed over different cultivars of seed propagated artichoke, are analysed in order to know the influence on earliness, yield, quality and crop behaviour. The experiment was carried out at the Experimental Station of Foundation Ruralcaja in Paiporta (Valencia, Spain), using six seed propagated cultivars, three with green heads (‘Imperial Star’, ‘Symphony’ and ‘Madrigal’) and three with purple heads (‘Opal’, ‘Opera’ and ‘Concerto’). On 21 July 2010 the potted plants were transplanted into a sandy loam soil, in lines 1.70 apart and 0.825 m between plants. Plants were sprayed three times every two weeks with GA3 at concentrations 0, 30, 60 and 90 mg L-1, starting on the 10 September. A foliar fertiliser was added at 0.1% (v/v) GA3 solution. In both green and purple head artichoke cultivars it was observed that the earliest cultivars need a lower concentration of GA3 (between 30 and 60 ppm) to produce in autumn, while late cultivars need highest concentrations of GA3 (90 ppm). In general, the greatest final yield was achieved by the control and the highest concentrations of GA3 induced to a lowering final yield, especially in the earliest cultivars. This reduction was also observed in late cultivars (‘Concerto’ and ‘Madrigal’) with the highest concentration (90 ppm). The largest GA3 concentrations produced initially a greater growing and an erect aspect of plants. On the contrary, the highest plant height was noticed in plants sprayed with the lowest concentrations of GA3 and in control plants.