Rice (Oryza sativa. L) genetic diversity for early vigor and drought ...

More documents

Recommendations

Info

IntroductionFigure 3. Dry-down experimental design in a greenhouse at IRRI (Los Banos, Philippines) fromSeptember to November 2010: (left) irrigated and packed (stressed) plants of a given genotype areplaced on the same table but separated by a small wall; (right) daily weighing of stressed plant potsand data registration using a bar code scanner.Water depletion and thus stress intensity was measured gravimetrically from stress onset (FTSW’ 1)at 6 th leaf stage on the main stem (Figure 1). This stage was chosen since it is representative of theexponential growth phase of seedlings before panicle initiation.At this stage it was checked thatseedling roots explore the whole soil volume contained in 1 liter pots. Therefore this system avoidsthe expression of genotypic differences in plant water availability and uptake (ie. drought avoidancemechanisms). The day before stress onset, the soil was fully re-watered from the top and thendrained overnight. The following morning pots were entirely covered with a plastic film to preventsoil evaporation and enable water loss only by plant transpiration. Pots were then weighed everymorning before 10AM. Pots of the well watered treatment were maintained in a flooded table butwere not submerged by the top. Two dry down experiments were performed during this PhD (Table1). Before each experiment, soil type and pot size was tested to check (i) if roots explored all the potvolume for a few contrasted genotypes (in terms of vigor) at 6 th leaf stage; (ii) if the dry-down wasslow enough in the chosen soil volume and thus if it was possible to observe gradual plant responseto stress establishment until FTSW’ 0.2; and (iii) the values of soil water content (humidity) at fieldcapacity and wilting point, needed for FTSW’ computation.In Montpellier (Exp1 in 2009), only two temporal replications were considered (for each genotypeand water treatment). The reason is that we encountered experimental problems with theenvironment monitoring system in the greenhouse during the third replication. Therefore the sameexperiment was performed at IRRI in 2010 (initially a reproductive drought phenotyping was20
Introductionplanned). The final harvest at FTSW’ 0.2 (targeted level of stress) was used to characterize shoot dryweight SDW and analyze soluble sugar and starch content in source (last ligulated) and sink (hidden,expanding) leaves. Plants were sampled before 10AM. A FTSW’ of 0.2 corresponds to a predawn leafwater potential of -0,8MPa (measured on exised ligulated leaves for one rice genotype with apressure chamber), thus considered as a severe stress, for the soil used in Montpellier. The methodused for sugar content analysis was based on HPLC chromatography for soluble sugars and enzymaticanalysis for starch content detailed in (Luquet et al. 2006). This method was not adapted to analyze alarge number of samples. Therefore only 43 genotypes were considered in a first step. Thesemetabolic analysis also shed light on assimilate abundance (source status) of the plant. Indeed, wedid not have the resources to measure assimilation rates on the entire panel. This was onlyperformed on 8 genotypes for the two replications in Montpellier to check for genotypic differencesunder well watered and drought conditions. The results were not used in this thesis because no suchdifferences were observed at statistically significant levels.At IRRI (Exp2), three simultaneous replications were monitored for all genotypes and treatments; theexperimental design was a bit improved compared to Montpellier (Exp1): stressed and well wateredplants were placed side to side in the same table (Figure 3) and additional shoot biomass samplingwas performed before stress application as well as a measurement of plant leaf area at finalsampling. During the dry-down, to optimize daily gravimetric data registration for each stressedplant, pots were tagged with a barcode. This allows a daily pot weight recording, instantaneouscomputing of FTSW’ and thus a precise final plant harvest at an FTSW’ value of 0.2. Daily plant leaftranspiration was calculated as the pot weight difference between two successive days and wasnormalized by plant leaf area (cm²), measured at final sampling and extrapolated to the days before(as explained in Chapter III) and potential evapo-transpiration (PET in mm)computed afterwards (seedetails in Chapter III).Table 1 Environmental characteristics during greenhouse experiments: experiment 1 in Montpellierand 2 at IRRI (Los Banos, Philippines).Experiment Characteristics Growing period Temperature (°C) Humidity (%) RG (MJ/m2) Soil Properties(Min- Max) (Min- Max) (mean) (1 litter pot)Experiment 1Montpellier France 2 repetitions 09/02/2009 to 22-33 27- 62 4,59 wp:0,11; Fc: 0,593,9° 43,6' alt: 20 2treatments 12/05/2009 Silty Clay Loam Soil (451g)Experiment 2Los Banos Philipinnes 3 repetitons 16/09/1010 to 25 - 36 65 - 79 6,97 wp: 0,15; Fc: 0,6214° 10' alt: 66 2 treatments 05/11/2010 Upland Soil (930g)21
Page 1 and 2: IntroductionMontpellier Supagro2, P
Page 4 and 5: Introductionahora ya puedes decir q
Page 6 and 7: IntroductionTable of contentsAknowl
Page 8 and 9: IntroductionIntroductionCONTEXTHost
Page 10 and 11: IntroductionRice crop performance u
Page 12 and 13: IntroductionEarly vigor was also re
Page 14 and 15: Introductionconsidering traits in a
Page 16 and 17: IntroductionPhotosynthesis is one o
Page 18 and 19: IntroductionThis PhD work focuses t
Page 22 and 23: IntroductionREFERENCESAsch, F., Sow
Page 24 and 25: IntroductionGlaszmann, J. C., Benoi
Page 26 and 27: IntroductionMcNally, K. L., Childs,
Page 28 and 29: Introductionbiotechnologically and
Page 30 and 31: Introduction30
Page 32 and 33: IntroductionINTRODUCTIONEarly vigor
Page 34 and 35: IntroductionThe underlying hypothes
Page 36 and 37: IntroductionMeasurement of environm
Page 38 and 39: IntroductionRESULTSRange of environ
Page 40 and 41: Introduction5050Frequency403020Exp1
Page 42 and 43: IntroductionTable 2: Matrix of corr
Page 44 and 45: Introductionwhether DR affected RGR
Page 46 and 47: Introductiontwo different rice dive
Page 48 and 49: IntroductionCONCLUSIONSThis study t
Page 50 and 51: IntroductionMcNally K, Childs KL. (
Page 52 and 53: IntroductionChapter II : Phenomics
Page 54 and 55: Introductiongrowth (leaf appearance
Page 56 and 57: IntroductionTable 1 Description of
Page 58 and 59: IntroductionFTSW ' AW WPFC WP(Eq.1)
Page 60 and 61: IntroductionIn Eq.5 d and c are the
Page 62 and 63: IntroductionFigure 1 Factorial plan
Page 64 and 65: IntroductionEffect of water deficit
Page 66 and 67: IntroductionRelations between const
Page 68 and 69: IntroductionCorrelations among drou
Page 70 and 71:
IntroductionGenotype clustering bas
Page 72 and 73:
IntroductionSimilar numbers of vari
Page 74 and 75:
Introductiona b c3210302520151050sh
Page 76 and 77:
IntroductionADP-glucose pyrophospho
Page 78 and 79:
Introductionobserved in well watere
Page 80 and 81:
IntroductionHe, H. Y., Koike, M., I
Page 82 and 83:
IntroductionTisne, S., Schmalenbach
Page 84 and 85:
IntroductionChapter III : Does earl
Page 86 and 87:
Introductionrate (DR, defined as th
Page 88 and 89:
IntroductionMean minimum and maximu
Page 90 and 91:
Introduction10AM to monitor water l
Page 92 and 93:
IntroductionSpearman correlation an
Page 94 and 95:
IntroductionTable 1. Broad sense he
Page 96 and 97:
IntroductionAll drought response va
Page 98 and 99:
IntroductionDo genotype groups havi
Page 100 and 101:
Introductioninvestigated, but none
Page 102 and 103:
IntroductionTable 6 Partial conting
Page 104 and 105:
Introductiong.PT -1cm.leaf rank -13
Page 106 and 107:
Introductionbecause in rapidly expa
Page 108 and 109:
IntroductionThe normalization of TR
Page 110 and 111:
Introductionmonitoring of transpira
Page 112 and 113:
IntroductionKato, Y., Hirotsu, S.,
Page 114 and 115:
IntroductionZhao, D. L., Atlin, G.
Page 116 and 117:
IntroductionSynthesis, discussion a
Page 118 and 119:
Introduction(Phenomics of Rice for
Page 120 and 121:
IntroductionConsequently, as descri
Page 122 and 123:
Introduction Depending on the genot
Page 124 and 125:
Introductionunder well watered cond
Page 126 and 127:
IntroductionDiversity panels can al
Page 128 and 129:
IntroductionRichards, R. A. and Luk
Page 130 and 131:
IntroductionAppendix I Article Luqu
Page 132 and 133:
Introductiontraits (Chapman et al.
Page 134 and 135:
Introductiona- Organ initiation rat
Page 136 and 137:
IntroductionSome model parameters w
Page 138 and 139:
Introductionshow restrained tiller
Page 140 and 141:
IntroductionPlasto:CR (0.730) > SDW
Page 142 and 143:
Introductioneffects on early plant
Page 144 and 145:
Introductionassimilate invested, th
Page 146 and 147:
Introductionsignal state variable.
Page 148 and 149:
IntroductionItoh JI, Hasegawa A, Ki
Page 150 and 151:
IntroductionTABLESTable 3 : list of
Page 152 and 153:
IntroductionTable 3. Stepwise multi
Page 154 and 155:
IntroductionIctMGRPlastoKrespTbKdfE
Page 156 and 157:
IntroductionTDW (g)108642DR = 0.025
Page 158 and 159:
Introduction158
Page 160 and 161:
Introduction160
Page 162 and 163:
Introduction162
Page 164 and 165:
Introductionétablissement de la cu
show all

Rice (Oryza sativa. L) genetic diversity for early vigor and drought ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?