Rice panicle temperature and crop microclimate in stressfull thermal environments: towards a model of spikelet sterility Cécile Julia PhD directed by Michael Dingkuhn (CIRAD) and Folkard Asch (Hohenheim University)
CONTEXT Global: l Climate Change RISOCAS project (Hohenheim university) + CIRAD My PhD study: Thermal stress at the reproductive stage for floaded rice 2 main sensitive stages : cold at the early microspore stage (disruption of meiosis) and at flowering (failure of panicle exsersion) heat at the flowering (affects pollination and fertilization processes) STERILITY PREVIOUS STUDIES ISSUES
Chilling at the young microspore stage: 1) Irrigated rice sowing date experiment in semi-arid environment at Ndiaye, Sénégal é (ARC) Problem of Tb: - Using air T, model-fitted Tb was 14-16 C - Using microclimatic corrections, it was 9-12 C - Calculation of thermal time is prone to errors (Dingkuhn and al., 1995) 2) Irrigated rice in Japan (Shimono and al., 25) Spikelet sterility is better predicted using panicle temperature (Tp) = f(culm position) = combination of water temperature (Tw) and air temperature (Ta) Microclimate + Organs Temperature = parameters to be taken into account
Heat at the flowering stage (anthesis) AirT and plant organst can differ a lot under stressing thermal conditions Irrigated rice in Senegal (dry season 21) 45 4 Ta (panicle layer) Ta (2m) 35 3 Ta (canopy) Tdry Tpanicle Tflagleaf mpérature ( C) 25 2 Twater Twet Te 15 1 5 Environnement 18/5/21, 12:44 Rad= 734.9 W/M² RH = 22%, ws= 3.8 m/s 5 1 15 2 Position par rapport au sol (cm) Panicle Temperature «Key» parameter
SCIENTIFIC APPROACH OF THE ISSUES What are the relationships between climate, microclimate, canopy structure, and organs temperature at sensitive stages? What are the links with the sterility and yield loss observed at maturity? 1) EXPERIMENTING IN THE FIELD In climatically contrasting sites For 7 contrasting varieties 2) CREATING A GREAT DATASET 3) ANALYSING 4) MODELLING (CIRAD SAMARA) The relationships G E
1) FIELD EXPERIMENTS Irrigated Rice Varieties: IR64, N22, Chromrong, Sahel 18, Sahel 22, IR463, IR72 Contrasting environments: CFR, France 29 (temperate summer) IRRI/Philippines 29 (DS, tropical-favourable) - Production + ARC/Senegal 21 (cold and hot DSeasons, tropical semi-arid)
Different sites, seasons, and climates: Temperature e ( C) 9 85 8 75 7 65 6 55 5 45 4 35 3 25 2 15 1 5 Senegal Dry Season 21 Harmattan 7/5 11/5 15/5 19/5 23/5 27/5 31/5 4/6 8/6 12/6 16/6 2/6 Date 25 2 15 1 5 Rg (MJ.m- -²) Ta_max Ta_min Rg RH = 65.8% ± 11% Temperature e ( C) 95 9 85 8 75 7 65 6 55 5 45 4 35 3 25 2 15 1 5 Philippines Dry Season 29 1/3 14/3 18/3 22/3 26/3 3/3 3/4 7/4 11/4 15/4 19/4 23/4 27/4 1/5 5/5 Date 25 2 15 1 5 Rg (MJ.m- -²) Ta_max Ta_min Rg -5 RH = 85.6% ±6% -1 Temperature ( C) 9 85 8 75 7 65 6 55 5 45 4 35 3 25 2 15 1 5 Senegal Cold Season 21 Heat stress 2/1 26/1 1/2 7/2 13/2 19/2 25/2 3/3 9/3 15/3 Date 25 2 15 1 5 Rg (MJ.m-²) Ta_max Ta_min Tw_max Tw_min Rg RH = 53.9% ± 16% ( C) Temperature 9 85 8 75 7 65 6 55 5 45 4 35 3 25 2 15 1 Chilling stress 5 France Summer Season 29 2/8 28/7 29/7 3/8 4/8 5/8 6/8 7/8 8/8 9/8 1/8 11/8 Date 25 2 15 1 5 ) Rg (MJ.m-² Ta_max Ta_min Rg RH = 68.3% ± 1%
Environment and Plant Measures: from booting to the end of flowering (Daily measurements) CANOPY STRUCTURE TEMPERATURE GRADIENT 2m Rn LAI at flowering Rg Rrefl Air and RH above the canopy Ta, RH Canopy and plant heights Panicle position Tp Tfl (Net radiometer) Panicles and Flag leaf temperature during anthesis (IR camera) Air and RH inside the panicle layer Tpl, RHpl Fl position Fl length and width Fl-1 position Last nodes position Air inside the canopy Tcan Water level Water Tw Soil Ts -3cm
PLANT MEASUREMENTS Micrometeo + Phenology observations + Yield and YC + Spike sterility N22 IR72 Sahel18 Chomrong InfraRed Sahel22 IR46-3 IR64
SOME RESULTS AND ANALYSIS IN PROCESS
PHENOLOGY Duration to flowering depends on environment and variety From Sowing to 5% Flowering Number of da ays 16 15 14 13 12 11 1 9 8 7 6 5 4 3 2 1 Phil_DS Sen_DS Sen_CS Fr_cam CHROMRONG N22 Sahel 18 IR R64 IR Variety R72 IR46_3 3 Sahel 22
SENSITIVE PERIODS FOR STERILITY AND GRAIN FILLING AD= Booting Heading Anthesis Grain filling Maturity Time Tpanicle TGW (filled) Tmin (air and water) Sterility (Cold) Tpanicle Time of anthesis Sterility (Heat) Tmin (canopy) Sterility (non exserted spikelets) Assimilats «False shortage Sterility»
COLD STERILITY exemple of the cold season in Senegal Plant measures Auricule Distance (AD) young microspore stage = Between -16 and -1cm (Satake and al., 197; Imin and al., 26) Panicle position Fl position Fl length and width Fl-1 position AD< AD= AD> Last nodes position (Flag leaf inside) Panicle exsersion at flowering (non exserted sterility) Microspore stage dates (cold sterility)
Meteo and micrometeo at the microspore stage Time (week from AD=) Variety Rep Tmax (air) Tmin (air) Tmoy (air) RHmo y Tmax (water) Tmin (water) Nd of days with Ta_min < 13 C Nd of days with Ta_avg < 2 C Nd of Nd of days with days with Ta_max Tw_min < > 3 C 16 C -2 CHROMRONG 1 24, 14,8 7 7 6 11-2 CHROMRONG 2 35,9 11, 21,9 4,4 25,1 14,8 7 7 6 1-2 CHROMRONG 3 25,9 14,3 7 7 6 9-1 SAHEL18 1 34,2 11, 21,7 38, 2,8 15,1 5 2 7 5-1 SAHEL18 2 34,2 11, 21,7 38, 21,2 16,1 5 2 7 2-1 SAHEL18 3 34, 11, 21,1 46,1 21,7 15,1 5 8 7 4-1 IR64 1 23,8 15,7 4 8 7 3 34,2 11, 21,11 49, -1 IR64 2 21,1 14,8 4 8 7 5 CHROMRONG 1 27,3 18,4 7 CHROMRONG 2 24,6 18,9 7 39,7 15,8 24,8 52,1 CHROMRONG 3 22,5 18,6 7 SAHEL18 3 18,9 7 SAHEL18 1 24,1 14,8 1 1 7 1 34,5 11,4 22,6 58, SAHEL18 2 23,1 15,9 1 1 7 1 IR64 1 18,2 7 39,7 15,2 24, 55,7 IR64 2 25,1 18,2 7 CHROMRONG 1 27,4 16,7 2 2 5 CHROMRONG 2 24,1 17,3 2 2 5 31,8 12,7 22,5 58,6 CHROMRONG 3 23,6 16,5 2 2 5 SAHEL18 3 16,9 2 2 5 1 SAHEL18 1 23,2 16,3 1 7 39,7 13,4 24,7 47, SAHEL18 2 23, 16,9 1 7 IR64 1 17,4 2 1 6 33,8 12,7 23,6 51,8 IR64 2 21,9 16,6 2 1 6 CHROMRONG 1 26, 18,1 1 2 1 2 CHROMRONG 2 27,9 13, 2,8 77,6 24,4 18,3 1 2 1 CHROMRONG 3 23,6 18,1 1 2 1 Sterility induced by cold at microspore stage is explained mainly by the window -2 to week before AD= Variety CHROMRONG 1 CHROMRONG 2 CHROMRONG 3 SAHEL18 1 SAHEL18 2 SAHEL18 3 IR64 1 IR64 2 Nd of 1 h days with % grains Rep Tw_min < sterility weight 16 C (g) Yield (t/ha) 11 39,9 22,3 4,42 1 21,6 23,8 376 3,76 9 18,6 28,3,76 (rats) 5 98,7 26,2 1,1 2 97,2 26,6 1,6 4 98,7 25,5 2,31 3 86,5 21,6 259 2,59 5 86,4 2,7 1,48 5% of tillers of the subplot have passed the microspore stage Regression can be done using data from other Risocas sowing date
HEAT STERILITY exemple of the hot season in Senegal IR photos analysis (Sahel 18):
(chromrong)
Tp at anthesis for 3 different varieties Temper rature ( C) 38 36 34 32 3 28 26 24 22 2 18 16 14 12 1 8 6 4 2 19/5/21-13:1 - Anthesis N22 IR64 CHROMRONG Variety Rg = 21.8 W.m-² RH = 21.8 % Ta = 37.2 Tp Tfl Tw = 26.8 % grain ste erility Position of the panicle layer (cm) 5 4 High 3 Medium Low 2 1-1 N22 IR64 Chromrong -2-3 -4
TIME OF ANTHESIS: Flower Opening Time (FOT) Observations in the field + Photos 1: 5 am 11: 2 am 13: 2 am Before anthesis Anthesis After anthesis FOT = 11:2
TIME OF ANTHESIS: FOT Location Ta_min = 23.8 C ±.8 Phil_DS_29 Ta_min = 21.5 C ±1 Sen_DS_21 Ta_min = 16.5 C ±2.4 Sen_CS_21 Time 8am 9am 1am 11am 12pm 1pm 2pm 3pm Fr_cam_29 Ta_min =18.5 C ± 1.6 Ta but also RH and Rg before anthesis + Genotype dependant Controled environment (Jagadish and al., 28), field experiments (Kobayasi and al., 21) => Include Micrometeo in the analysis
5/19/21 Ta ( C C), RH (%) 8 7 6 5 4 3 2 1 5/2/21 Ta ( C C), RH (%) 8 7 6 5 4 3 2 1 1 3 2 1 9 8 7 6 5 4 3 2 1 3 8 16 24 32 4 48 1 2 1 Time of day (hr) 48 16 8 24 12 32 16 4 2 48 24 Time of day (hr) 9 8 7 6 5 4 3 2 1 Solar Rad diation (W.m m-²) m-²) Solar Rad diation (W. Ta Tw RH Rs Ta Tw RH Rs FOT 1: Chromrong 2: Sahel 18 3: IR64
IN PROCESS Phenology and Morphology (H plant, H fl,h p ) var/date MacroClimate at 2m (T, H, Rad, vent) date/hh/mm Microclimate (gradient de T, H) var/date/hh/mm Organs temperatures(t p, T fl ) var/date/hh/mm/ss Extraction (var/date/hh /mm) Dataset Variety, stage, morphology, environment, Torgans Biological analysis Sterility and TGW correlated with «historical» conditions of micro and agrometeo = Observations time shifted Including micrometeo data in the FOT analysis Physics Physical analysis of the relation between organ temperature energy balance and canopy morphology
To be continued Thank You
IR64 8 7 Sahel 18 Chromrong 1 9 ) Ta ( C), RH (% 6 5 4 3 2 8 7 6 5 4 3 2 Solar Ra adiation (W W.m-²) FOT Ta Tw RH Rs 1 1 48 16 8 24 12 32 16 4 2 24 48 Time of day (hr)
IR64 8 Sahel 18 1 7 Chromrong 9 Ta ( C), RH (%) 6 5 4 3 2 8 7 6 5 4 3 2 Sol lar Radiatio on (W.m-²) FOT Ta Tw RH Rs 1 1 8 16 24 32 4 48 4 8 12 16 2 24 Time of day (hr)
«Old» spikelets New spikelets