Parthenocarpic fruit production in loquat (Eriobotrya japonica Lindl.) by using gibberellic acid

This study evaluates the effect of gibberellic acid (GA(3)) in inducing parthenocarpy in 'Algerie' loquat, as well as the optimum treatment conditions and associated techniques, hand thinning and ringing, to produce seedless fruit with high enough quality for fresh consumption. GA(3) applied in the course of the phenological growth stages 504-508 of the BBCH-scale produced seedless fruits, with the magnitude of the response depending on the concentration applied and number of treatments. Percentage of panicles bearing seedless fruitlets significantly increased with increasing GA(3) concentrations up to 100 mgl(-1) and significantly and positively correlated with the number of treatments applied. Trees treated three times with 100 mgl(-1) developed more than 90% of panicles bearing almost 7 seedless fruits per panicle, which were smaller in size, drier and slightly acid but similar in TSS concentration and skin colour than seeded fruits from untreated trees. Fruit thinning to 3 fruits per panicle did not increase seedless fruit size, but ringing performed at the onset of cell enlargement stage, growth stage 702 of the BBCH-scale, significantly increased fruit size by 12-15%, depending on the year. Trees treated three times with 100 mgl(-1) of GA(3) and ringed produced 26 kg, on average, of seeded fruit of suitable commercial quality. (C) 2010 Elsevier B.V. All rights reserved.