Improvement of Plant Yield - an Achievement of Innovative Plant Protection Strategies :Heinz Wilhelm Dehne

INRES-Phytomedicine – University of Bonn

Improvement of Plant Yield – an Achievement of Innovative PlantProtection Strategies

Heinz-W. Dehne

University of Bonn

Development of fungicides:

- seed treatments against smut (Tilletia caries)

- protective chemicals against Phytophthora infestans (potato famine)

- plant systemic chemicals (benzimidazoles) - exhibiting curative activity





- development of azoles (triazoles) – with broad spectrum activity= protective and curative= strong effects on host plant physiology (cytokinin-like effects)






- development of morpholines (broad spectrum, further mode of action)= ideal for counteracting against azole resistance of fungal pathogens

- development of strobilurins (different systemicity)= systemicity influenced plant physiology and plant stress resistance






- development of morpholines (broad spectrum, further mode of action)= ideal for counteracting against azole resistance of fungal pathogens

- development of strobilurins (different systemicity)= systemicity influenced plant physiology and plant stress resistance

- carboxamide fungicides = further mode of action and increasing photo-synthetic activity and resistance against abiotic stresses

Penetration and distribution of different Strobilurines in and on the plant(mod. n. Bartlett et al. 2002)

properties of Strobilurines

penetration in leaf very limited to middle

redistribution by vapour phase not existent to existent

stability in plants limited to distinct

phloem-mobility none

transport into growing parts not existent to existent

translaminar transport limited to distinct

xylem-mobility not existent to existent

Influence of Strobilurines on yield of winter wheat(‘Orestis’)

F+F-1 (EC 75):SEPTSP 5,2%PUCCRE 2,3% +18%

+26%

0

2

4

6

8

10

12

controluntreated

2x Azole 2x Strobilurines

Yiel

d [

t/ha

]

Influence of fungicide application on green leaf area and yield in kernels

0

20

40

60

80

100

EC 69 EC 73 EC 83

gree

n le

af a

rea

(%)

untreatedAzoleStrobilurine

*

*

0

20

40

60

80

100

120

91,8

untreated

yiel

d in

dt/h

a

104,5

Azole

+ 14%

112,5

Strobilurine

+ 23%

Influence of selected fungicides on quality* of wheat protein('Ritmo')

338

369 373

290

300

310

320

330

340

350

360

370

380

390

untreated Azole Strobilurine

Indi

ce d

e ch

ute

[ s

]

* Indice de chute (Hagberg)

0

20

40

60

80

100

untreated

Azole

Green leaf area of wheat in dependence of fungicide-application ('Kanzler’, Mean F bis F-3)

30.05EC 39

05.06.EC 47

14.06.EC 67

25.06.EC 71

08.07.EC 75

15.07.EC 81

Leaf

are

a F

–F-

3 [

% ]

14.05EC 32

22.07.EC 87

0

20

40

60

80

100

untreated

Azole

Green leaf area of wheat in dependence of fungicide-application ('Kanzler’, Mean F bis F-3)

30.05EC 39

05.06.EC 47

14.06.EC 67

25.06.EC 71

08.07.EC 75

15.07.EC 81

Leaf

are

a F

–F-

3 [

% ]

14.05EC 32

1. treatment 2. treatment

22.07.EC 87

damage bypowdery mildew

0

20

40

60

80

100

untreated

Azole

Strobilurine

Green leaf area of wheat in dependence of fungicide-application ('Kanzler’, mean F to F-3)

30.05EC 39

05.06.EC 47

14.06.EC 67

25.06.EC 71

08.07.EC 75

15.07.EC 81

gree

n le

af a

rea

F –

F-3

[ %

]

14.05EC 32

1. treatment 2. treatment

22.07.EC 87

Strobilurine-effect

damage bypowdery mildew

untreated Strobilurine 2 x

Delay in ripening

Azole 2 x Strobilurine 2 x

delay in ripening II

increase in yield

increased CO2-uptake

changes of phytohormone

levels

reduction of pathogens and

saprophytes

increased

photosynthetic rate

“greening effect”

reduced

respiration rate

Effects of Strobilurines on physiology of wheat plants

Mitochondrium

inner membrane of mitochondriae

Matrix

Cristae

Construction and function of mitochondriae

Matrix

Intracristae-hole

Mito

chon

dria

l mem

bran

Q

QH2

Q/QH2

Pool

Succinat-Dehydrogenase

Succinat

2 QH2

complex III

2 Q -

2 Q

QQ -

QH2

SFe Fe

SFe (c1)

Fe (b1)

Fe (bh)

2 H+

Q0 - site

Q1 - site

Fe (S)

2 H+2 H+

Antimycin AFuniculosin

strobilurine

Electron transport chain of mitochondriae and target ofStrobilurines ( n. Jagow, 1989; QoI und QiI)

Fumarat

-

complex II

Electrontransport of photosynthesis

grana-stack

chloroplast

thylakoid-membrane

Electron transportchain of chloroplasts andtarget of Strobilurines

PC

PC

LHC II LHC IICP47CP43

D2 D1

Cyt

b-5

59

Cyt b IV

RieskeCyt f

LHC I LHC I

PsaA PsaB

PsaF

FA FB

PsaL

FNR

Thyl

akoi

d-M

mem

bran

P700

FX

A1

A0

PsaC

PsaD PsaE

NADPH/H+NADP+

2 H+

Cyt

2 H+2 H+

H2O

2 H+ 1/2 O2

MnMn

MnMn

P 680Z

PheoPheo

D

QA QB

2 H+

QZ

Fe2S2

QC

PQ/PQH2

FD

FDStrobilurine

+Stroma

Intrathylakoid-space

modified after Rich et al. 1991

Important biosynthesis pathways stimulated by energy from chloroplasts

CO2-Assimilation

SO42- -Assimilation

NO2--Reduction

CO2 + 4 H+ + 3 ATP C + 2 H2O

SO42- + 6 Fd red + 4 H+ + 2 ATP S2-

NO2-- + 6 Fd red + 8 H+ NH4 + 2 H2O

Production of energy and reduction-equivalents

(ATP und NADPH + H+, etc.)

Chlorophyll Fluorescence-Measurement in the field

detection clip on wheat leaf

0,0

0,1

0,2

0,3

0,4

0,5

0,6

EC 65 EC 75 EC 85

effe

ctiv

e qu

antu

m e

ffici

ency

of P

S II

untreated

Azole

yield in dt/ha

83,7

84,4

Influence of location and fungicide application at quantum efficiency of PSll and yield of grain (Meckenheim)

(SNK-Test, p<0,05)

ab

a

b

a

0,0

0,1

0,2

0,3

0,4

0,5

0,6

EC 65 EC 75 EC 85

effe

ctiv

e qu

antu

m e

ffici

ency

of P

S II

untreated

Azole

Strobilurin A

Strobilurine B

Strobilurine C

yield in dt/ha

83,7

84,4

87,7

87,4

87,3

(SNK-Test, p<0,05)

cc

c

c

cc

ab

a

b

a


0,0

0,1

0,2

0,3

0,4

0,5

0,6

EC 65 EC 75 EC 85

effe

ctiv

e qu

antu

m e

ffici

ency

of P

S II

untreated

Azole

Strobilurine A

Strobilurine B

Strobilurine C

76,0

86,8

92.3

91,4

91,2

yield in dt/ha

(SNK-Test, p<0,05)

c

c

b

c

a

c

c

c

b

a


equipment

Gas exchange measurements in the field

equipment with gas cooling

Chlorophyll Fluorescence-Measurement in the field

cuvetteoptimal illumination

Influence of Wheat genotype on increase of yield by Strobilurines (3 Locations)

(SNK-Test, p<0,05)

0

1

2

3

4

5

6

7

8

Kanzler Jonas Flair Hybnos Gorbi Hanseat

Yiel

d in

crea

se [d

t/ha]

abab

b

aa

ab

Influence of Strobilurines on utilisation of water in wheat('Kanzler‘, F-1, EC 71)

untreated

Azole

Azole + Strobilurine

utilisation of water [ µmol / mmol ]0 2 4 6 8 10 12 14

0

10

20

30

3d p.a. 7d p. a. 10d p.a.assi

mila

tionr

ate

in µ

mol

CO

2/ m

2le

af a

rea

/ sec

.

Azol Strobilurin Azol + Stress Strobilurin + Stress

drought stress

Increase of Strobilurins and dry stress on wheat leaf assimilation (flag leaf)

Increase in yield

increased CO2-uptake

changes in phytohormones

reduction of pathogens and

saprophytes

increase of

photosynthetic rate

“greening effect”

modified Stress-reactions

Institute for Plant Disease University Bonn

reduced

respiration rate

Effects of Strobilurines on crop physiology inwheat plants

Conclusions: Positive effects of modern fungicides

• Strobilurines exert – before onset of senescence - an influence on the assimilation rate of plants

• additionally the increase in yield correlates with conservation of green leaf area

• Independence of susceptibility or resistance of variety

• Independence of yield potential of variety

• Plant genotype shows influence upon crop physiology of Strobilurines

• Strobilurines improve ability of compensation of plants

Mycotoxin concentration in wheat ears and efficacy of fungicide treatment:

___________________________________________________________________

mycotoxin treatment concentration (ng/g) average maximum

___________________________________________________________________Deoxynivalenol untreated 2 263 6 601

azole ear application 464 508azole leaf & ear appl. 255 998

15-acetyl-DON untreated 130 232azole ear application 0 0azole leaf & ear appl. 0 0

Enniatin B untreated 108 227azole ear application 2 118azole leaf & ear appl. 1 117

___________________________________________________________________

Innovative Plant Production and Plant Protection: _________________________________________________________________

- Control of organisms competing with host plants for space, nutrients, water – and even pests and plant diseases

- Improve plant yield and efficacy on a more an more getting smallerspace – save natural resources

- Combat international exchange and trade – transmission of pathogensand pests by trade and worldwide exchange


- Control of organisms competing with host plants for space, nutrients, water – and even pests and plant diseases

- Improve plant yield and efficacy on a more an more getting smallerspace – save natural resources

- Combat international exchange and trade – transmission of pathogensand pests by trade and worldwide exchange

- Avoid resistance to herbicides, insecticides and fungicides by thedevelopment of suitable plant protection strategies

- Make successfully use of innovative and environmentally safecompounds with beneficíal side effects on host plant physiology

-- Include innovative decision making technologies assisting the

practical farmer – one example: use of hyperspectral imaging


- innovative herbicides, insecticides and fungicides need to be plant systemic

- the chemicals have to be compatible with the crop plant




- the chemicals are generally single-site inhibitors

- so they are subject to resistance and need anti resistance strategies




- the chemicals are generally single-site inhibitors

- so they are subject to resistance and need anti resistance strategies

- innovative techniques have to assist the farmers to carry out the rightmeasures at the right time (e.g. in diagnosis of damaging agents)

- plant protection systems have to be adapted to different situationsand need to be optimized

Science

Improvement of Plant Yield - an Achievement of Innovative Plant Protection Strategies :Heinz Wilhelm Dehne