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Sustainable low-input cereal production: required varietal characteristics and crop diversity

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Sustainable low-input cereal production: required varietal characteristics and crop diversity Working Group 4: plant-plant interactions About SUSVAR . – PowerPoint PPT presentation

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Title: Sustainable low-input cereal production: required varietal characteristics and crop diversity


1
Sustainable low-input cereal productionrequired
varietal characteristics and crop diversity
  • Working Group 4 plant-plant interactions

2
About SUSVAR.
  • System characteristics
  • Cereal production
  • Low-input conditions
  • Aims
  • Increased stability (yield and quality)
  • Increased resource use efficiency
  • Main means
  • Better use of crop genetic diversity

3
Better use of crop genetic diversity (1)
  • Selection of suitable genotypes
  • Better use of available gene-pool for low-input
    systems
  • Varieties that are well suited to low-input
    conditions in general
  • Varieties that are well suited to specific
    conditions (environmental conditions by
    definition more variable than under high-input
    conditions)

4
Better use of crop genetic diversity (2)
  • Use of mixtures
  • Utilize more genotypes simultaneously
  • Heterogeneity contributes to stability (risk
    avoidance)
  • Generation of added value
  • Facilitation
  • Competition

5
Crop - environment mutual interaction
environment
Crop A
6
Facilitation positive effect
environment

crop
Crop A
Crop B
7
Facilitative production principle insects
8
Competition negative influence
environment
-
crop
Crop A
Crop B
9
Competitive relations are important
10
Competition also the basis for over-yielding
  • Competitive production principle
  • intra-specific competition gt inter-specific
    competition
  • Niche-differentiation or complementarity
  • ? better exploitation of available resources

11
Facilitative production principle weeds
  • Facilitation
  • (the creation of a weed free environment)
  • is through
  • Competition
  • (suppression of weeds by other crop)
  • Challenge avoid other crop from developing into
    a weed.

12
Facilitative production principle weeds
13
Working group plant-plant interaction
  • Crop weed interaction
  • Weed suppression
  • Which traits
  • General or environment specific
  • Easy screening procedures

14
In case of mixtures
  • Crop crop interaction
  • Yield stability
  • Difference in stress-tolerance
  • Productivity
  • Niche differentiation
  • Intra-specific competition gt inter-specific
    competition

15
Weed suppression of mixtures
  • Crop crop weed interaction
  • How to maximize weed suppression?
  • Combine most competitive cultivars
  • Maximize complementarity
  • Complementarity in resource use and acquisition
  • Complementarity in weed suppression mechanism

16
Currently many different questions .
  • What do we want to obtain with mixtures?
  • (stability, productivity, weed suppression,
    others)
  • How can added value of mixtures be obtained?
  • (what is the best strategy)
  • How to select individual varieties for their
    performance in mixtures?

17
Time to decide on where to go
18
(No Transcript)
19
Organisation of activities and reciprocal
benefits
WG 3 Plant Soil Interactions
WG 4 Plant Plant Interactions
WG 1 Genetics Breeding
WG 6 Variety testing certification
WG 2 Biostatistics
WG 5 Plant Disease Complex
20
Facilitative production principle diseases
21
Plant-plant interaction
  • Main issues
  • Productivity
  • Stability
  • Weed suppression

22
Learning-objectives
  • To familiarise with options for evaluating
  • productivity
  • competitive relations
  • within intercropping systems
  • To be able to value the various methodologies
  • To learn the relationship between some indices of
    relative competitive ability

23
Multiple cropping
  • Growing two or more crops on the same field in a
    year
  • - sequential cropping
  • - relay intercropping
  • - full intercropping

time
24
Reasons for intercropping
  • Better use of available resources
  • (land, labour, light, water, nutrients)
  • Reduction in pest pressure associated damage
  • (diseases, insects, weeds)
  • Socio-economic
  • (greater stability, risk avoidance, food/cash
    crops)
  • Sustainability
  • (erosion, soil fertility)

25
Facilitative production principle diseases
Causal organism Magnaporthe grisea two
phases vegetative stage Leaf blast reproductive
phase Neck or panicle blast
26
Intercropping as weed management component
Leek monoculture
weed-free period
manual weeding
mechanical weeding
Weeds
Leek-Celery Intercrop
weed-free period
mechanical weeding
Weeds
Transplanting
Harvest
27
Competition the basis for over-yielding?
  • Niche-differentiation
  • ? better exploitation of available resources
  • separation in time (relay)
  • separation in space (rooting depth)
  • different resource capture abilities
  • different growth requirements

28
Key to evaluation of intercrop productivity
  • Quantification of competitive relations
  • Example
  • Two-species mixture (sp 1 - sp 2)
  • How many competition coefficients?

29
Key to evaluation of intercrop productivity
  • Quantification of competitive relations
  • Example
  • Two-species mixture (sp 1 - sp 2)
  • How many competition coefficients?
  • 2 intraspecific competition coefficients b11,
    b22
  • 2 interspecific competition coefficients b12,
    b21

30
Intraspecific competition
YN/(b0b1N) ? WY/N1/(b0b1N) ? 1/Wb0b1N
31
Measure of intraspecific competition
  • 1/W1b10b11N1
  • b10 plant/g
  • b11 m2/g
  • b11/b10 m2/plant
  • crowding coefficient (de Wit)
  • ecological neighbourhood area (Antonovics Levin)

32
Intercropping intra and interspecific
  • 1/W1b10b11N1 b12N2
  • b11/b12 relative competitive ability
  • What does this value learn us?

33
Intercrop productivity
  • 1/W1b10b11N1 b12N2
  • and
  • 1/W2b20b22N2 b21N1
  • b11/b12 and b22/b21
  • Niche differentiation index (NDI)
  • b11/b12 b22/b21 (b11b22)/(b12b21)
  • NDI 1,lt1,gt1

34
How can we determine these indices?
35
Evaluation in practice
  • Experiment with three treatments
  • Monoculture of species 1? Y1,mono
  • Monoculture of species 2 ?Y2,mono
  • Mixture of species 1 and 2 ?Y1,mix, Y2,mix
  • Calculation of Relative Yield
  • RY1 Y1,mix/Y1,mono
  • RY2 Y2,mix/Y2,mono
  • Land Equivalent Ratio (LER)
  • LER RY1 RY2
  • relative land area under sole crops required to
    produce the yields achieved in intercropping

36
Two basic designs
  • Additive design
  • 0 0 0 0 x x x x 0 x
    0 x 0 x 0 x
  • 0 0 0 0 x x x x 0 x
    0 x 0 x 0 x
  • 0 0 0 0 x x x x 0 x
    0 x 0 x 0 x
  • 0 0 0 0 x x x x 0 x
    0 x 0 x 0 x
  • 0 0 0 0 x x x x 0 x
    0 x 0 x 0 x
  • species 1 species 2 mixture

37
Two basic designs
  • Replacement design
  • 0 0 0 0 x x x x 0
    x 0 x
  • 0 0 0 0 x x x x 0
    x 0 x
  • 0 0 0 0 x x x x 0
    x 0 x
  • 0 0 0 0 x x x x 0
    x 0 x
  • 0 0 0 0 x x x x 0
    x 0 x
  • species 1 species 2 mixture

38
Replacement design
  • Overall density constant
  • Results represented in a replacement diagram
  • LER generally replaced by Relative Yield Total
    (RYT)
  • Relative crowding coefficient (k) to express
    competitive relations
  • k12(1-z1)/(w11/w12-z1)
  • z1fraction species 1

39
Replacement design
  • k ? intrasp/intersp comp.
  • Similar to b11/b12?
  • kk
  • related to intercrop productivity
  • 1, gt1, lt1
  • Similar to NDI?

40
Excercises
  • Complete calculations on two intercrops
  • grown at two different densities
  • in replacement and additive design
  • Focus on
  • What is the difference between outcomes from a
    replacement and an additive design?
  • What is the difference between relative crowding
    coefficient (k) and the ratio of competition
    coefficients (e.g. b11/b12)?
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