Flower manipulation 27th May 2015

• Brief overview of project

• Brief discussion about understanding of flowering in mango and manipulation tools

• Presentation of ethephon and KNO3 trials 2014/15

• Proposed next steps

Short term• Optimisation of existing chemicals

KNO3

EthephonPaclobutrazol

• Better use of weather data

Medium term• New genetics

• NMBP• New chemicals

Longer term• New tools

Bud age: 90 days.

Preferentially second flush buds

leaves recurved

Aspect “stand by”, grayish leaf color, aspect crunchy

Low nitrogen content: 1.0 – 1.3%

Plant condition for floral induction (Brazil)

Plant condition for floral induction (Brazil)

Phenological cycle0 50DAYS

EN

D O

F H

AR

VE

ST

0 30 40 50 60 130 160 180 190 200 210 240 290 300 DAYS

HA

RV

ES

T

700

600

400

200

0 F

ruit

wei

ght

- g

PR

UN

ING

AN

D

FERTIL

IZATIO

N

STA

RT F

LUSH

ING

CU

LTA

R

GR

OW

TH

STO

PPED

- E

TH

EPH

ON

Beg

inn

ing

flora

l in

du

ctio

n

Flora

l in

du

ctio

n F

inis

hed

Fl

ow

eri

ng

st

art

s Fu

ll flow

eri

ng

FL

OW

ER

ING

FIN

ISH

ED

F

IRS

T F

RU

IT A

BO

RTIO

N

SEC

ON

D F

RU

IT A

BO

RTIO

N

Growth curve of fruits.

K2Olinha da NIL

CO

EF

ICIE

NT

- K

cPOTENTIAL EVAPOTRANSPIRATION – ETp 1,000,900,800,700,600,500,400,300,200,100,00

VEGETATIVE PHASE / FLUSH MATURATION WATER STRESSDORMENCY

(RETORNO)2nd

Fruit Abortion

FRUITGROWTH

Fruit induction

HA

RV

ES

T

What assists Mango flowering

• Mature leaves, recurved, hard green, crunchie

• Cool weather (<20oC)

• Growth (At the right time)

• Paclobutrazol (Cultar® Payback ®)

• Ethephon (Ethrel ® Galleon ®)

• KNO3 (Nitrate)

• Cincturing (Potentially Destructive)

• Low leaf N levels (<?)

Delaying growth using ethephon

Use ethephon to prevent vegetative growth after the wet

Use ethephon to hold a second vegetative flush after the wet

Use ethephon to spread flower initiation both on an individual farm or within a district

Properties of Ethephon

Label; temperature >18oC and <32oC

Many crops use non-ionic wetters

Store product in Cool location(4oC vs 45oC)

DO NOT apply to weak or stressed plants.

DO NOT apply if rain is expected within 8 hours of application.

DO NOT mix with hard (alkaline) water.

Ethephon

Registration application prepared by AMIA

Permit granted

Needs follow up research for final registration

Time (24h)

0 500 1000 1500 2000Tem

perature/Relative H

undity/ Wind S

peed

0

20

40

60

80

100

Temperature (oC)Relative Humidity (%)Wind speed (Km/h)

Why are we spraying at night?

Low temperatures

Less wind

Slower drying

but

Stomata closed

Darwin weather 15.06.2014

TreatmentsSpray 8/05/2014 Treatment 1 Water plus LI700 1ml/lTreatment 2 290 g ai/ha (0.67 ml/L) ethephon plus 1ml/l LI700 Treatment 3 580 g ai/ha (1.34 ml/L) ethephon plus 1ml/l LI700 Treatment 4 870 g ai/ha (2.01 ml/L) ethephon plus 1ml/l LI700 Treatment 5 3% KNO3 plus 1ml/l LI700

Spray 21/05/2014

Repeat

Spray 10/06/2014 “Turned irrigation on”

12 trees of 25 with 3% KNO3 plus 1ml/l LI700

Spray 12/06/ 2014

Same 12 trees of 25 with 1.5% KNO3 plus 1ml/l LI700

Flowering Date

Predicted Harvest date

10-May 29- Aug20-May 9- Sep30 - May 19- Sep

1-Jun 20-Sep5-Jun 24-Sep

10-Jun 29-Sep15-Jun 4-Oct20-Jun 7-Oct25-Jun 12-Oct30-Jun 16-Oct5-Jul 20-Oct

10-Jul 24-Oct15-Jul 28-Oct20-Jul 1-Nov30-Jul 9-Nov

Importance of South Easterlies

Date 2014

May Jun Jul Aug Sep Oct

Te

mp

era

ture

oC

5

10

15

20

25

30

35

40

45

Darwin Temperatures (o C) 2014

Sprayed with 3% KNO3 10/6/2014 and 1.5% KNO3 on 12/6/2014

Stage 1 Stage 2

Stage 3 Stage 4

Stage 5

Treatment Flowering East Flowering WestWater 0.0 0.0KNO3 4.8 5.4

Ethephon 290 0.0 0.0Ethephon 580 0.0 0.0Ethephon 870 0.1 0.0

Response 10th June 2014

Plus KNO3 Minus KNO3

Side West East West EastWater 44.4 56.4 26.9 51.0KNO3 41.9 38.3 35.0 36.0

Ethephon 290

54.7 61.1 42.9 57.2

Ethephon 580

50.5 55.9 32.5 32.1

Ethephon 870

45.0 53.8 41.0 48.1

Response 10th August 2014

Flush stage

Treatment 1 2 3 4 5

water OK OK OK OK OK

290 g ai/ha X? X X X OK

580 g ai/ha X? X X X OK

870 g ai/ha X? X X X X

1160 g ai/ha X X (X) X (X) X (X) X

Observations

Variable response on buds, killed outer scale leaves

Highest dose killed shoots

Highest dose effected light green fully expanded leaves

High dose killed shootsDefoliated shoots

2015 trials18th March• Control (Bugmaster)• 1% K2SO4

• Ethephon 580g ai/ha, plus LI700 18th April• Ethephon 960g ai/ha plus LI700 • 2.5% KNO3 (5 rows) plus LI700

21st May• 2.5% KNO3 (The farm) plus LI700

March April MayDate

Mon 16 Mon 30 Mon 13 Mon 27 Mon 11 Mon 25

Tem

pera

ture

(oC)

0

10

20

30

40 Cum

ula

tive h

ours

belo

w 2

0o C

2015

100

200

300

400

0 100 200 300 400 500 600 700 800 900 10000

20

40

60

80

100

120

140

R² = 0.830775803644346

FloweredLinear (Flowered)No Flowers

Chill Sum (Below 20 degrees over flushing period)

Flus

hing

Per

iod

(day

s)B74

Next steps

• Describe ethephon effects on leaves

• Review Paclobutrazol use.

• Investigate factors affecting KNO3 uptake. Formulation, Boron and Zinc, Wetters, time of day, concentration, leaf age as part of bigger N program

• Assess the role of K2SO4 on flush development