Effect of Gibberellic Acid and Harvesting Time on the Seed Quality of Four Okra Cultivars

In an experiment at the University of Thessaly during the summer season of 2011, the effect of foliar application of gibberellic acid (GA3) to okra at an early stage of plant growth (3-4 leaves) on plant growth, pod and seed characteristics was studied in relation to harvest time. GA3 was applied at concentrations of 0 (Control), 50, and 100 mg L-1 to four okra cultivars (‘Boyiatiou’, ‘Veloudo’, ‘Clemson’ and ‘Pylaias’) and pods were harvested 30, 35, 40 and 50 days after anthesis (DAA) from the lower part of the plant. From the results it was found that GA3 application increased plant height irrespective of cultivar and GA3 concentration (50 and 100 mg L-1), but without increasing flower induction or pod set. Similarly, GA3 had no effect on pod dimensions (which were determined by genotype) or mean 100 seed weight, except in Boyiatiou. Similarly, GA3 application did not consistently affect seed moisture content, but it did however, increase the number of seeds per pod. Germination was either promoted (‘Veloudo’), inhibited (‘Boyiatiou’) or not affected (‘Pylaias’, ‘Clemson’) by GA3. Differences in germination were apparently related to the incidence of hard seeds. Storage of seeds for 18 months improved germination. Overall, pod and seed characteristics were affected more by genotype and harvest time than by GA3 application.