Australian Stonefruit Grower Magazine Issue 2 August 2016 | Page 37
Research
ETHYLENE SAMPLING
PROTOCOL
The following equipment is required to sample fruit
ethylene:
•
Fruit pre-measured and labelled for IAD and
grouped into 0.1 IAD value increments.
•
Respiration chambers: Sealable air tight jars or
containers between 500 mL and 1 L capacity
depending on availability (see Appendix A)
•
Evacuated vials: supplied by
DEDJTR Horticultural Production
Sciences team.
•
25 cc syringe: with 25G needle.
•
Timer/clock.
•
Scale to record fruit weight.
•
Recording sheets
ABOVE: Equipment needed
to perform the procedure of
sampling fruit ethylene. A
example of a glass chamber of
approximately 1L volume.
LEFT: Example of plastic chamber
of approximately 1L volume.
Download
See video
Ethylene collection recording
sheet
How to sample ethylene from
stonefruit
makes the process less costly and allows
for systematic identification of maturity
with the DA-Meter must be taken immediately
prior to the collection of ethylene samples so that
IAD can then be used to identify maturity classes.
For each cultivar tested, ethylene measurement
should be conducted at IAD values between 0.2
Mature
Ethylene Production Rate
classes for each cultivar. Measurements of IAD
10
8
Commercial
6
Immature
4
2
and 1.7 for stone fruit and between 0.2 and 1.9 for
pome fruit. Best results are achieved if ethylene
is measured at IAD increments of 0.1. At least
5 individual fruit are required for each ethylene
production measurement. This procedure will
allow the creation of cultivar specific graphs
correlating IAD and ethylene production from
which it will be possible to accurately identify
maturity classes (Fig. 1).
summerfruit.com.au
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
DA Meter Reading
Figure 1. Nectarine Autumn Bright ethylene production and
segregation in maturity classes of similar ethylene behaviour
correlated to DA values. Maturity classes were: Mature = ripe
(climacteric fruit), Commercial = usual maturity at commercial
harvest (On-set of climacteric) and Immature = unripe (preclimacteric fruit).
august 2016 | Australian Stonefruit Grower
37