LIBRO-CONGRESO-CITRUS

S06
S06P07
Pre-harvest rind breakdown in New Zealand and a comparison with similar problems reported
from other countries
Pyle K.R.
Pyle Orchards and Consulting Pty Ltd, New Zealand. kpyle@xtra.co.nz
Pre-harvest rind breakdown is an occasional problem on mandarins, tangelos and oranges in New Zealand.
It usually affects fruit at or soon after colour break and is often referred to as ‘on-tree oleocellosis’. It is
normally associated with extreme wet, cold weather events and with gusty winds. In the Gisborne region
in July 2011, some exposed, wet orchards, mainly navel oranges, were adversely affected with up to 50%
fruit marking and 60% fruit drop in the worst cases.This prompted a more detailed examination of the
condition, a review of the local meteorological and other factors that may have caused the breakdown and
some recommendations for growers. These are described, together with a brief comparison of similar preharvest
rind defects and their management obtained from international literature and correspondence.
The condition most closely resembles pitting of ‘Pineapple’ orange described in Florida, pitting of ‘Fortune’
mandarin reported in Spain, rind staining of navels and tangelos in Morocco, mandarin rind disorder in
California, rind spotting of clementines in Greece and ‘pateta de rata’ or ‘colapso de la corteza’ on ‘Navelate’
in Spain and Chile.
S06P08
The effect of combined spraying of gibberellin and prohydrojasmon on peel puffing in satsuma
mandarin
Ikoma Y., Matsumoto H.M., and Sato K.S.
NARO Institute of Fruit Tree Science (NIFTS), Citrus Research Division, Japan. yoshino@affrc.go.jp
Peel puffing of satsuma mandarin is a serious physiological disorder in which the pericarp and flesh separate.
This disorder causes increased fruit rot and decreases eating quality. Because peel puffing is promoted by
high temperatures and humidity, there is a fear that global warming will cause frequent occurrence of peel
puffing. To reduce peel puffing effectively, combined spraying of the plant hormones gibberellin (GA) and
prohydrojasmon (PDJ) was examined. In the present study, 3 chemical sprays (1 mg∙L -1 GA spray, 1 mg∙L -1
GA plus 25 mg∙L -1 PDJ spray and 1 mg∙L -1 GA plus 50 mg∙L -1 PDJ spray) were prepared just before treatment.
On August 29, the selected branches of satsuma mandarin trees were treated with these chemical sprays,
respectively. At optimum harvesting time, fruit qualities were investigated. Peel puffing was significantly
inhibited by combined spraying of GA and PDJ but not by spraying of GA without PDJ. There was no difference
between two combined sprays (1 mg∙L -1 GA plus 25 mg∙L -1 PDJ spray and 1 mg∙L -1 GA plus 50 mg∙L -1 PDJ
spray) in the intensity of the peel puffing inhibition. Coloring was delayed by combined spraying of GA and
PDJ but not by spraying of GA without PDJ. The intensity of the delay of coloring was smaller in 1 mg∙L -1 Ga
plus 25 mg∙L -1 PDJ spray than in 1 mg∙L -1 GA plus 50 mg∙L -1 PDJ spray. In TSS, there was no difference among
treatments. In contrast, citric acid content became high by combined spraying of GA and PDJ. Especially
in 1 mg∙L -1 GA plus 50 mg∙L -1 PDJ spray, the increase in citric acid content was remarkable. These results
suggested that the optimum concentrations of GA and PDJ for inhibition of peel puffing were 1 and 25 mg∙L -1 ,
respectively.
S06P09
Production cost reduction of Shiranuhi mandarin hybrid in plastic house cultivation using
underground air and air mixer.
Han S.H.
Jeju National University (JNU), Horticulture, Korea, Republic. sangheon@jejunu.ac.kr
The Jeju citrus area is located in a cold area, but cultivation is generalized using plastic film houses.
The late maturing mandarin variety ‘Shiranuhi’ started to be grown in 1990 and it has reached 1,188 ha
100 - VALENCIA CONFERENCE CENTER, 18th-23rd NOVEMBER 2012