Effects of forchlorfenuron and abscisic acid on the quality of 'Flame Seedless' grapes.

摘要

Forchlorfenuron (CPPU), a synthetic cytokinin, applied after fruit set increases the size and firmness of table grapes beyond what is possible without CPPU treatment. However, treatment with CPPU may inhibit colouring of cv. Flame Seedless grapes, limiting its use to growing areas where colour has been consistently poor. In contrast, application of abscisic acid (ABA) to cv. Flame Seedless grapes may cause fruit softening, which is undesirable, but its primary effect is to increase anthocyanins content and fruit colour. The hypothesis that application of CPPU followed by ABA may increase the size and firmness of cv. Flame Seedless grapes without excessively inhibiting colouring was investigated. Grapes were treated with 0 or 20 g h-1 CPPU (applied at fruit set) and 0, 300 or 600 mg l-1 ABA (applied at veraison) in 2005 and with 0, 5, 10, 15 or 20 g ha-1 CPPU and 0, 200, 400 or 600 mg l-1 ABA in 2006. Both plant growth regulators (PGR) increased berry mass, but grapes treated with CPPU were as firm, or firmer, than untreated grapes, whereas those treated with ABA were of similar or lesser firmness. Treatment with CPPU generally reduced soluble solids and red berry colour, whereas treatment with ABA reduced titratable acidity and increased red colour. The PGR did not interact to affect any of the fruit quality variables measured, so beneficial effects of CPPU or ABA were apparent whether the grapes were treated with either or both PGR. Combined use of CPPU and ABA may be a desirable cultural practice for cv. Flame Seedless table grapes.