Download Managed stress system (MSS) - 18th Australian Cotton Conference

Breeding cotton for a variable rainfall environment
18th Australian Cotton Conference, Broadbeach, QLD
Warren Conaty, David Johnston, Alan Thompson, Susan Jaconis, and Greg Constable
August 11th 2016
CSIRO AGRICULTURE AND FOOD
CSIRO rainfed breeding program
Initial
Evaluations
(Narrabri)
Parental
Selection
F2& F3
Evaluations
F4 Single
Plant
Selection
Progeny Rows
Preliminary Onsite
onsite
location
(Narrabri)
Intermediate
Advanced Material
2 | Managed water stress to improve rainfed breeding | Warren Conaty
Preliminary Offsite
Intermediate
Advanced Material
Up to 5
offsite
locations
Australian rainfall patterns
Highly variable rainfall
– Summer dominant
– Average 650mm
– In-crop 350mm
– Skewed
Figure 1. (a) Frequency of in-crop rainfall and (b) variability in monthly in-crop
rainfall for Narrabri.
3 | Managed water stress to improve rainfed breeding | Warren Conaty
The problem
One-in-five years has low yield (<550 kg ha-1) and has no statistical
difference between genotypes
i.e. we cannot reliably select superior lines.
4 | Managed water stress to improve rainfed breeding | Warren Conaty
Hypothesis
Application of a single furrow irrigation in dry
years will increase trial yields above the threshold
of statistical genotypic resolution
5 | Managed water stress to improve rainfed breeding | Warren Conaty
Aims
1. To determine if and when a single irrigation could be applied to
rainfed evaluations when yield is expected to fall below the
confidence threshold
(Crop Modeling)
2. To assess the stability of germplasm performance under both
rainfed conditions and limited water situations
(Field Trials)
6 | Managed water stress to improve rainfed breeding | Warren Conaty
Development of:
Managed stress system (MSS)
Result: An irrigation should be applied to a ‘rainfed’ experiment when
soil water deficit reached 90-100mm by 100-110 DAS
7 | Managed water stress to improve rainfed breeding | Warren Conaty
Field Validation: MSS
0
Soil water deficit (mm)
*
80
*
100
120
140
160
Nov
40
*
60
*
80
100
120
140
Rainfed
MSS
Dec
2014/15
20
40
60
*
2013/14
*
20
Soil water deficit (mm)
0
*
Jan
Feb
Mar
Apr
160
Nov
Dec
Jan
Feb
Mar
Apr
Figure 4. Soil water deficit for each season in Rainfed and MSS treatment
0
2015/16
Soil water deficit (mm)
20
40
60
80
100
120
140
160
Nov
Dec
Jan
Feb
8 | Managed water stress to improve rainfed breeding | Warren Conaty
Mar
Apr
• Three seasons
• 21 genotypes grown under rainfed
and managed stress
• Soil water deficit measured via
neutron attenuation
• Yield analysis
MSS
Rainfed
MSS Validation- Results
Avg. trial
yield
(kg ha-1)
Genotype
p-value
546
0.329
16.4
MSS
1121
0.008
9.9
Rainfed
785
0.002
11.0
MSS
1324
0.004
7.8
Rainfed
823
<0.001
14.1
n/a
n/a
n/a
Sowing
Treatment
year
2013
2014
2015
Rainfed
MSS
9 | Managed water stress to improve rainfed breeding | Warren Conaty
Rainfall
(mm)
127
199
350
Co-efficient Treatment
of variation x genotype
(%)
p-value
0.726
0.020
n/a
Interactions
Genotype rankings differed significantly between rainfed and MSS in
2014/2015.
• different rainfall and crop
fruit setting pattern.
• driven by low and medium
yielding genotypes
• high yielding genotypes are
consistent
• interaction is no longer
significant when looking at
multiple years
Figure 5. Rainfed and MSS rankings for lint yields (2013/2014 and
2014/2015).
10 | Managed water stress to improve rainfed breeding | Warren Conaty
Main Conclusions
• Developed a managed stress system that optimized a single
irrigation to meet yield threshold
• Irrigating the MSS was necessary to resolve genotype differences in
2013/14
• When rainfed yields increase due to rainfall, the MSS was not
necessary to resolve genotype differences
MSS
11 | Managed water stress to improve rainfed breeding | Warren Conaty
Rainfed
What does this mean for our breeding program?
• Using the MSS, we are able to get useful data in years when yields would be too low to
evaluate genotypes
• Since grower income is greater under better environments than very limited water
situations, genotype performance under MSS may actually identify better and more
realistic long term options for growers.
• Best performing genotypes under rainfed conditions in dry seasons will also be
captured. Rainfed genotype evaluation is repeated over multiple seasons and sites and
genotype selection is based on all sites, not just MSS.
12 | Managed water stress to improve rainfed breeding | Warren Conaty
CSIRO rainfed breeding program
Initial
Evaluations
(Narrabri)
Parental
Selection
F2& F3
Evaluations
F4 Single
Plant
Selection
Progeny Rows
MSS
onsite
location
(Narrabri)
Preliminary Onsite
Intermediate
Advanced Material
13 | Managed water stress to improve rainfed breeding | Warren Conaty
Preliminary Offsite
Intermediate
Advanced Material
5 offsite
locations
Thank you
Thank you to the technical staff of CSIRO cotton breeding group,
particularly Mark Laird, Mick Price, Adam Suckling, Megan Cameron, Deon
Cameron, Jo Price and Kellie Cooper for their invaluable contribution to
this work.
CSIRO cotton breeding is undertaken in the Cotton Breeding Australia joint
venture between CSIRO and Cotton Seed Distributors.
CSRIO AGRICULTURE AND FOOD
Dr Warren Conaty
Research Scientist
[email protected]
CSIRO AGRICULTURE AND FOOD