Changes in Endogenous Hormone Levels during the Ripening of Grape Cultivars Having Different Berry Set Mechanisms

Authors: NİLGÜN GÖKTÜRK BAYDAR, NİHAT HARMANKAYA

Abstract: Concentrations of indole-3-acetic acid (IAA), gibberellic acid (GA_3) and abscisic acid (ABA) were measured by gas chromatography (GC) in the berries of 3 grape cultivars having different berry set mechanisms to elucidate the possible relationship between endogenous hormones and berry set mechanisms. The results obtained showed that the levels of IAA, GA_3 and ABA in seeded Italia, empty seeded Çavuş and stenospermocarpic seedless Perlette changed during ripening. While Italia exhibited a hormonal pattern similar to that of Çavuş, Perlette showed a different IAA and ABA pattern compared to the other cultivars. Generally, IAA and GA_3 were high in the early stages of berry growth. The concentrations of IAA and GA_3 in the berries declined to very low levels at the time of ripening. On the other hand, changes in ABA levels were closely associated with ripening. The highest contents of hormones were found in Italia and the lowest in Perlette. Çavuş was placed between them with intermediate concentrations. From the results, it was concluded that there may be a close relationship between hormone contents in berries and the degree of seed development.

Keywords: grape, berry set, indole-3-acetic acid, gibberellic acid, abscisic acid

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