Articles
EFFECT OF PACLOBUTRAZOL ON HARVEST MATURITY, FRUIT STORABILITY AND VEGETATIVE GROWTH OF ‘TRIUMPH’ PERSIMMON (DIOSPYROS KAKI THUNB.)
Article number
1007_101
Pages
849 – 856
Language
English
Abstract
Export opportunities to the European market exist for out-of-season persimmon fruit.
Thus early fruit (April) sell at a much higher price than late (mid-May to June) fruit.
The South African persimmon industry has adopted the use of the plant growth regulator paclobutrazol (PBZ) at a standard rate of 1.5 g per plant to advance harvest maturity.
However, at this application rate, PBZ results in stunted growth and a decline in fruit keeping quality.
The aim of this research was to investigate the effect of lower PBZ application rates on fruit maturity and fruit keeping quality as well as vegetative growth.
The experiment was conducted in Triumph persimmon orchards at Simondium in the Western Cape Province of South Africa.
Treatments included an untreated control, 1.5 ml PBZ soil drench on 14 December 2009, 0.75 ml PBZ drench on 14 December 2009 and 17 February 2010, 0.75 ml PBZ drench on 14 December 2009 and 0.375 ml PBZ drench on
14 December 2009. In the second season, trees were left untreated as per current industry practise.
In the first season, all the PBZ treatments advanced harvest maturity regardless of rate.
The effect of the highest PBZ application rates (1.5 ml PBZ drench and 0.75 ml PBZ drench twice) on harvest maturity carried through to the subsequent season.
On average, PBZ decreased fruit firmness and increased the percentage soft fruit at the end of the shelf-life period in the first season.
In the subsequent season, firmness at harvest decreased while the percentage soft fruit at the end of the shelf life period increased linearly with increasing PBZ application rate.
Halving the PBZ application rate to 0.75 ml per tree may advance harvest maturity in the season of application, but without improving storability or vegetative growth compared to the standard application rate of 1.5 ml per tree.
The halved rate will also not advance harvest maturity in the subsequent season.
Thus early fruit (April) sell at a much higher price than late (mid-May to June) fruit.
The South African persimmon industry has adopted the use of the plant growth regulator paclobutrazol (PBZ) at a standard rate of 1.5 g per plant to advance harvest maturity.
However, at this application rate, PBZ results in stunted growth and a decline in fruit keeping quality.
The aim of this research was to investigate the effect of lower PBZ application rates on fruit maturity and fruit keeping quality as well as vegetative growth.
The experiment was conducted in Triumph persimmon orchards at Simondium in the Western Cape Province of South Africa.
Treatments included an untreated control, 1.5 ml PBZ soil drench on 14 December 2009, 0.75 ml PBZ drench on 14 December 2009 and 17 February 2010, 0.75 ml PBZ drench on 14 December 2009 and 0.375 ml PBZ drench on
14 December 2009. In the second season, trees were left untreated as per current industry practise.
In the first season, all the PBZ treatments advanced harvest maturity regardless of rate.
The effect of the highest PBZ application rates (1.5 ml PBZ drench and 0.75 ml PBZ drench twice) on harvest maturity carried through to the subsequent season.
On average, PBZ decreased fruit firmness and increased the percentage soft fruit at the end of the shelf-life period in the first season.
In the subsequent season, firmness at harvest decreased while the percentage soft fruit at the end of the shelf life period increased linearly with increasing PBZ application rate.
Halving the PBZ application rate to 0.75 ml per tree may advance harvest maturity in the season of application, but without improving storability or vegetative growth compared to the standard application rate of 1.5 ml per tree.
The halved rate will also not advance harvest maturity in the subsequent season.
Publication
Authors
M. Bill, K.I. Theron, S.F. Ungerer, W.J. Steyn
Keywords
fruit maturity, firmness, keeping quality, percentage soft fruit
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