Key Postharvest Duties for Key Grower Level

Postharvest PersonnelDr. George Staby

Perishables Research Organization

February 26, 2014Bogotá, Colombia

Getting information after today

• George Staby’s e-mail address• georgestaby@chainoflifenetwork.org

• English vs. Computer Spanish• http://translate.google.com/

• Answering questions is free (so ask!)• Questions (e-mail in either language)

• Answers (in English and computer Spanish)

• Care and handling eManual (more on this subject later)

Key topics for today’s program

• Temperature (shade, precooler, color)

• Water relations (hydration, dry handling)

• Ethylene (importance, Florel test)

• New product (elicitor, stimulator, residues)

• eManual (postharvest information on your own computer / mobile device that you can obtain by e-mail)

Three key factors affecting the postharvest performance of flowers

• Temperature

•Temperature

•Temperature

Poor storage/transport temperatures increase respiration and heat produced, while reducing vase life

Temperature

(degrees C)

Respiration and

heat formed

(carnations &

roses)

Increase in heat

& respiration

compared to

0 C

0 92 -

10 280 3.0 times higher

20 2438 26.5 times higher

30 4794 52.1 times higher

Some average flower arrival temperatures in Miami

Origin Crop Boxes ˚F ˚C

Bogotá Roses 30,329 61.3 16.3

Bogotá Carns 15,856 60.3 15.7

Medellin Mums 8,485 61.9 16.6

Quito Roses 3,948 63.4 17.4

Quito Other 3,692 63.6 17.5

Possible vase life reductions when shipped via Miami or similar airport

u

30

40

50

60

70

80

90

0 12 24 36 48 60 72

50

60

70

80

90

100

0 24 48 72

Some temperature related factors youshould (must) control in postharvest

• Shade in greenhouse staging areas

• Shade from greenhouse to classification

• Light (white) colored plastic boxes

• Rack cooling initially or hydration in cooler

• Hydration / STS before grading / bunching

• Forced air precooling after bunching but before shipping (no more hydration)

Water relations

• Failure in water relations

• Water uptake < transpiration (loss)

• Xylem occlusion• Emboli (air)• Dirt / debris• Bacteria• Physiological plugs

Picture slides missing

• The slides you will see on the screen could not be put into the handout

Hydration tests - team approach

• Test results presented in the following tables are a consequence of the combined efforts between Bill DeBoer, laboratory scientist at Syndicate Sales, and myself, as a consultant working with Syndicate Sales

• E-mail address for Bill DeBoer:

wdeboer@syndicatesales.com

Internal (inside stems) vs. external (in solutions) blockage levels

• External levels mean little unless enough gets inside the water conducting stem tissue (xylem) to block water movement up the stems

• Therefore, internal blockage levels can be a better predictor of hydration treatment effectiveness and subsequent flower quality than hydration solution levels

Measuring internal rose stem blockage levels (bottom 2.5 cm)

• 3 rose cultivars hydrated 1 or 24 hours

• Products tested (all freshly made*)• HydraPlus

• Hydraflor 100

• RVB / Pro Series 1

• Chlorine + citric acid* (homemade)

• HydraQuik dip then into plain water

• Quick Dip then into plain water

Relative internal blockage levels in the bottom 2.5 cm of rose stems(blockage levels per gram (~2 cm) stem tissue)

Product

Inside blockage after

one hour hydration

Inside blockage after

24 hour hydration

HydraPlus 268 2,302

Hydraflor 100 43,189 285,446

RVB / Pro Series 1 2,465 69,020

Chlorine / citrate 6,332 1,111

Quick Dip* 4,081 1,068

HydraQuik* 45 36

Average 9,397 59,831

Commercial implications

• When treated with HydraQuik dip, the water conducting tissues of cut flowers have about 1,010 times less blockage (and therefore are about 1,010 times cleaner) compared to the average of the common homemade chlorine-based and purchased commercial hydration products used in this test

Fresh weight increase as influenced by product and hydration time

ProductFresh weight increase after

one hour hydration (g)Fresh weight increase after

24 hours hydration (g)

HydraPlus 2.1 6.4

Hydraflor 100 2.2 6.5

RVB / Pro Series 1 1.9 6.2

Chlorine / citrate 1.6 6.1

Quick Dip 2.7 6.5

HydraQuik 2.7 6.2

Average 2.2 6.3

Vase life (days) as influenced by product and hydration time

ProductAverage vase life 1 hour hydration

Average vase life 24 hours hydration

HydraPlus 6.4 6.3

Hydraflor 100 6.3 5.8

RVB / Pro Series 1 6.2 6.4

Chlorine / citrate 6.0 5.7

Quick Dip 5.9 6.0

HydraQuik 6.7 5.8

Average 6.3 6.0

Commercial implications

• One hour hydration is generally sufficient but 1-2 hours is what to aim for

• One hydration treatment before bunching

• No hydration treatments after bunching

• Are there exceptions like very hot days?

• Stem ends “even” prior to dip version

Bunching considerations(benefits for receivers)

• Cut stem ends even (all touch flat surface at the same time)

• Stem tie located at least 10 cm up from cut ends

• Not “hook” ties (demonstrate)

• No more than 1/3 foliage removed

• Hydration before bunching, not after

Rose vase life as influenced by plus or minus re-cutting at receiver level (bunching technique relationship)

All hydration products

Average vase life not re-cut

(days)

Average vase life re-cut

(days)

Average 5.8 6.5

Commercial implications

• As expected, re-cutting stems at receiver level is important

• Previous research showed that re-cutting stems at receiver level is generally even more important if an aluminum sulfate containing hydration solution is used

• Hence, make sure the bunches you make are “re-cutter friendly”

Summary: Hydration time (1-2 hours) and use proper hydration solution

• Hydrated only once

• For everyday harvest and for flowers that are to be stored at grower level (hydrate once after storage, before shipping)

• Less costly because less water, chemicals, storage space, and labor are utilized

• Petal bruising / Botrytis example with roses

Cleanliness

• Maintaining clean buckets and all solutions in which cut flowers are placed is critical (40% rule)

• If you are not willing to drink out a bucket, it is too dirty for flowers!

• Another advantage of more dry handling is that there are fewer buckets and solutions to keep clean

Apply protective treatments before shipping

• Ensure that flowers are properly treated with anti-ethylene, anti-yellowing, anti-water stress, enhancers, and/or fungicides prior to shipping to minimize postharvest losses and improve shelf life.

• Let’s review anti-ethylene and then enhancers

What is ethylene and how can it be measured?

• Ethylene is a gas that is naturally produced by flowers and plants

• Odorless at harmful concentrations

• Can only effectively measure using expensive laboratory equipment

What are some major sources of ethylene?

• Many flowers, fruit, and some vegetables

• Exhaust from gasoline, diesel, or propane

• Smoke from frost prevention and garbage burning fires

• Physically damaged flowers

• Disease infected flowers

• Banana ripening rooms (major problem)

Some reducing / preventing ethylene damage treatments

• Growing resistant species and cultivars (Florel test, liquid ethylene)

• Temperature

• Anti-ethylene treatments (STS and MCP)

• Minimize handling to reduce bruising

• No hydration after bunching roses

• Disease control

Cultivar / variety example

• http://www.youtube.com/watch?v=irxVYY9D6qs

• Can do using Florel test, which will be explained shortly

Temperature has a dramatic effect on how waxflowers respond to ethylene

Ethylene

(ppm)Temp (F) 12 hours 24 hours 36 hours 48 hours

0 35 0 0 0 0

1 35 0 0 0 0

10 35 0 0 0 0

100 35 0 0 0 0

0 68 0 0 0 0

1 68 40 84 72 78

10 68 58 98 100 98

100 68 72 98 100 100

ethylene treatment 0 °C

H2O STS MCP

ethylene treatment 20 °C

H2O STS MCP

The unfortunate and sad truth

• Not all STS / MCP treated flowers are protected from ethylene because:

• applied improperly (sachet example)

• chemical not active (STS)

• time from treatment too long (MCP)

• treatment time too short

• treatment temperature too low

• just a marketing ploy (never really applied)

Spray bottle and Florel

Florel test for ethylene sensitivity and STS / MCP effectiveness

• Find Florel sources on Internet and purchase one pint (500 ml), which is enough for many dozens of tests

• Amazon.com presently sells it for less than $20.00 per pint (500 ml)

• Use at least 1 bunch per test

• Spray half of the flowers to run-off with one ml (30 drops) Florel per 100 ml water

Florel test for ethylene sensitivity and STS / MCP effectiveness

• Place flowers in vases on table and observe over the next few days

• The sprayed and non sprayed flowers should look the same if the MCP or STS treatments were properly done and/or the flowers / plants are not ethylene sensitive

• If the sprayed ones die first, they were not properly treated with STS or MCP

Identify and market every floral crop by cultivar / variety name

• Red car and cerveza examples

• If one does not know the cultivar name of a flower, how can a grower determine if it should or should not be used again?

• At the same time, if consumers do not know the cultivar name of a flower, how can they determine if it should or should not be purchased again?

New product (not named yet) history

• Food industry (approved as a wash for use on certain food crops like fresh tomatoes)

• Improves flowers / plants abilities to resist certain postharvest disorders (elicitor, stimulator, enhancer)

• Improves looks of flowers and foliage (cleaning agent, great wetting actions)

• Demonstration

Some “new product” data(damaged rose petals per flower)

Rose cultivar Water Switch New Product

Jandiro 0 0.4 0.08

Freedom 0.6 0.3 0.3

Chardonnay 0 0.5 0

Variance 1.9 5.3 9.6

Rosita Vendela 7.5 2.2 2.1

Average 2.0 2.2 2.1

eManual

• In English (but can use free translators)

• http://www.chainoflifenetwork.org/

• Includes about 175 pages and over 900 hyperlinks to articles

• Syndicate Sales sponsored special – Free copy for all in attendance today

• I will send eManual to you by e-mail

• Need legible names and e-mail addresses

Review

• Harvest (shade, dry, white, time)

• Hydrate (dips), STS, cooler, (1-2 hours)

• Grading and bunching (tie, cut stem ends, leaves, sleeve, dry)

• Packing (+/- plastic, pregnant, strapping)

• Precooling (condensation)

• Ship (more on the same day harvested)

• eManual will be e-mailed to you

The “benefits” of holes in plastic sleeves

Thanks to Syndicate Sales / Elena Diaz for organizing today’s program

“Talk the Talk” or “Walk the Walk”?

“Proactive” or “Reactive”?

Questions and/or Comments (now)?

Questions and/or Comments (future)?