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Interaction of nitrogen fixation and water use efficiency in chickpeasPresented byCarola BlessingFaculty of Agriculture and EnvironmentUniversity of Sydney
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Competition for carbon between seeds and rhizobia
C assimilation
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Competition for carbon between seeds and rhizobia
C assimilation ?
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Natural abundance method to determine Ndfa
N2
δ15N= 0‰
δ15N plant
𝑁𝑑𝑓𝑎=𝛿15𝑁 𝑝𝑙𝑎𝑛𝑡−𝛿15𝑁 𝑟𝑒𝑓
𝐵−𝛿15𝑁𝑟𝑒𝑓
δ15N refB value=δ15N no soil N
N2
δ15N= 0‰
soil N δ15N ≠0‰
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Field trial with two contrasting desi chickpea genotypes
Sonali: drought tolerant
PBA Slasher: drought susceptible
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Field trial with two contrasting desi chickpea genotypes
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Main field trial- 2 genotypes- Treatment: irrigated vs. rainfed- N=6- Sampling: 6.-10. September 2015 (flowering)
& 3. October 2015 (early seed development)
Glasshouse- 2 genotypes- Well watered- Sampling at flowering and early seed
development
Expanded field trial- 26 genotypes- Treatment: irrigated vs. rainfed- N=2- Sampling: 6.-8. October 2015 (early seed
development)
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Higher Ndfa during seed development than during flowering
P-valueSampling <0.001
***Genotype
<0.001 ***
Treatment
0.06
Statistic (anova)
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No correlation between Ndfa and yield, but increased seed N concentration
Irrigated [kg/ha]
Rainfed [kg/ha]
Yield loss
Sonali
1590 1426 -10.3%
PBA Slasher
1536 1190 -22.6%
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Positive correlation between Ndfa and the difference in δ15N between nodules and leaves
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Increase in yield with increasing Ndfa
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Conclusion
– Higher Ndfa during seed development than during flowering
– Increased seed N concentration at higher Ndfa
– Positive correlation between Ndfa and the difference in δ15N between nodules and leaves relationship can be used to determine Ndfa of other genotypes
– Chickpeas profit from increased Ndfaalso during drought
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Dry period after first irrigation
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Phenology and management
50% flowering
First pod 75% maturity
Sonaliirrigated
72 100 129
Sonalirainfed
73 105 126
PBA Slasherirrigated
88 103 132
PBA Slasher rainfed
87 104 130
Planting: 11.6.2015Irrigation: 24.9.2015 15/10/2015
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Dry conditions caused water stress also on irrigated plots
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Yield neg related to δ13C in leaves and seeds, but mostly due to difference between treatmentsNdfa pos related to δ13C in seeds, but also mostly due to difference between treatments
Δ13C↑ Δ13C ↓
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No effect of genotype on δ13C valuesdrought increased δ13C in seedsδ13C in seeds generally higher than in leaves Statistic
(anova)Early seedP-value
Genotype
0.71
Treatment
0.11
Interaction
0.46
P-valueGenotype
0.12
Treatment
0.01 *
Interaction
0.62
<0.001 ***
