Phenotypic traits revealing root function under drought C. Mariano Cossani* & Matthew P. Reynolds

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1 Phenotypic traits revealing root function under drought C. Mariano Cossani* & Matthew P. Reynolds C. Mariano Cossani Associate Scientist Wheat Physiology Group- Global Wheat Program

2 Outline Background Phenotyping Approaches Conventional methods Related traits Latest (field) Technologies Application in Trait Based Breeding

3 SAWYT Data : All Locations Average genetic gains at 556 international sites: ~1% per year Manes et al Crop Science Sharma et al Crop Science

4 Drought Conceptual Model (YLD = WU x WUE x HI) Photo-Protection Transpiration Efficiency Leaf morphology: -wax/pubescence -posture/rolling Pigments -chl a:b -carotenoids Antioxidants WUE of leaf photosynthesis -low 12/13 C discrimination Spike/awn photosynthesis Functional stay-green Partitioning (HI) Pre-anthesis partitioning to stem carbohydrates Grain harvest index -dwarfing genes Buffering against reproductive failure -ASI (maize) -panicle extrusion (rice) Water Uptake Rapid ground cover -protects soil moisture Access to water by roots -indicated by cool canopy -osmotic adjustment

5 The study of growth of root systems and phenotype traits related to them is still a challenge in breeding It has been restricted by lack of high throughput methods

6 A priori requisites for correct phenotyping, and properly interpretation of results Major genes for phenology are not fixed in most experimental wheat populations RILs populations typically show a 30+ day range in flowering Because growth stages are not equally sensitive to stress, diverse phenology confounds effects of: weather fluctuation soil moisture depletion rainfall, temperatures

7 HTP Tools CT is one of the most useful physiological traits complementing breeding Fast 10 sec Economical $100 Effective Selecting for CT in addition to visual selection for plant type, improved the ability to identify the very highest yielding lines under drought

8 Deeper roots under drought confer stress adaptation CT=-0.20x+34.3, R 2 =0.88 Yield=2.07x+254.9, R 2 =0.35 Lopes and Reynolds (2010). Functional Plant Biology The ability of the roots to extract water at soil depth is linked to CT

9 CTv NDVIg Yield GM2 CTg CTv NDVIg CTg GM2 CTv Yield CHLg NDVIv Yield CTg CTv GM2 Common QTL identified for heat and drought adaptation Consistent QTL identified in the Seri/Babax Population 1B-a 2B-a 3B-b 4A-a B-a.aac/caa-4 1B-a.wPt B-a.wPt B-a.aca/cac-5 1B-a.gwm273 1B-a.wPt B-a.aac/ctg-4 1B-a.wPt B-a.agg/cat-4 1B-a.acc/cat-4 1B-a.act/ctc-7 1B-a.agg/cat-11 1B-a.barc065 1B-a.gwm413 1B-a.agg/ctg-5 1B-a.wPt B-a.aac/cta-5 1B-a.agg/cat-18 1B-a.gwm131 1B-a.agg/cac-3 1B-a.agc/cta-9 1B-a.agc/cta-2 1B-a.agc/cta-6 1B-a.agc/cag-5 1B-a.aag/ctg-14 1B-a.wPt B-a.act/ctc-9 1B-a.aca/cta-9 1B-a.gwm582 1B-a.gwm301b 1B-a.wPt B-a.aag/ctc-6 1B-a.wPt B-a.aca/cac-2 1B-a.wPt B-a.acc/ctc-4 1B-a.acg/cta-2 1B-a.act/ctc-5 1B-a.wPt B-a.aca/cag-5 1B-a.aca/caa-3 1B-a.agg/ctg-3 1B-a.aac/ctc-6 2B-a.wPt B-a.aac/cta-1 2B-a.wPt B-a.wPt B-a.aag/ctc-3 2B-a.wPt B-a.acc/ctc-2 2B-a.acc/ctg-4 2B-a.acc/ctc-10 2B-a.wPt B-a.aag/ctg-5 2B-a.agg/cat-7 2B-a.agg/cac-10 2B-a.agc/cag-4 2B-a.aag/ctg-15 2B-a.agg/cac-5 2B-a.gwm388 2B-a.acg/cta-1 2B-a.gwm191a 2B-a.aca/ctg-1 2B-a.aag/ctg-12 2B-a.act/ctc-11 2B-a.wPt B-a.wPt B-a.aca/caa-4 2B-a.agg/cta-3 2B-a.agg/cac-13 2B-a.agg/ctg-2 2B-a.act/ctc-1 3B-b.wPt B-b.aag/ctc-9 3B-b.gwm644 3B-b.aca/ctg-5 3B-b.gdm008 3B-b.wPt B-b.aac/cac-5 3B-b.wPt B-b.aag/ctc-1 3B-b.agg/cta-6 3B-b.wPt B-b.wPt B-b.acc/ctg-5 3B-b.wPt B-b.wPt B-b.aca/cag-9 3B-b.wPt B-b.wPt B-b.gwm301e 3B-b.aca/caa-9 3B-b.acc/ctg-11 3B-b.wPt B-b.acc/ctc-8 3B-b.wPt B-b.wPt A-a.gwm397 4A-a.act/cag-5 4A-a.act/cag-3 4A-a.wmc048d 4A-a.agg/cta-12 4A-a.aac/ctg-3 4A-a.wmc048c Pinto et al, TAG 121: Empty bars: Drought specific QTL Lined bars: Stress QTL specific for DRT & HOT environments Solid bars: Robust QTL identified under stress and irrigated environments

10 Precision phenotyping: spectral radiometry Photosynthetic area Pigment composition Hydration status Soil moisture Stem carbohydrates N status Growth analysis Agronomic traits Soil conductivity Mullan (2012)

11 NWI-3 predicts ψleaf, ψsoil and soil water content NEXT STEP?? Gutierrez et al. (2010). Journal of Experimental Botany

12 Aerial remote sensing phenotyping platforms M. Tattaris (CIMMYT)

13 Sean Thompson (PhD student)

14 Preliminary, and enthusiastic results show GPR was successful in the identification of wheat root mass in plot location under field survey conditions Thompson et al Thompson et al. 2013

15 Recent results reported a DNA-based method for studying root responses to drought in field-grown wheat genotypes Huang et al Sci. Rep. 3, 3194 No need of separation of roots from soil, it would maybe permit HTP of root responses to drought, and genetic resources screening in the field.

16 Opportunities for HTP Platforms Exploring Trait Diversity of Genetic Resources In situ landraces Oaxaca, Mexico ~ 0.5 million accessions of genetic resources in collections worldwide for wheat. The World Wheat Collection at CIMMYT has ~170,000 Dr. K.C. Bansal,India

17 Wide crossing with close relatives e.g. Synthetics Sources of disease resistance Redistribution of roots to deeper soil profiles under drought (Lopes & Reynolds, 2010) T. durum AABB X = T. tauschii DD Hexaploid synthetic AABBDD Lopes & Reynolds (2011). Drought adaptive traits and wide adaptation in elite lines derived from re-synthesized hexaploid wheat. Crop Science 51:1617

18 Difference (%) between SYN-DER and recurrent parents SYN-DER lines showed greater yield and total biomass than REC parents SYN-DER associated with decrease in root:shoot ratio especially under drought In direct response to drought, SYN-DER invest relatively less mass in surface roots (0-30cm)

19 Strategic Crossing to Accumulate Drought Adaptive Traits from Wheat Genetic Resources WUE: Photo-Protection Leaf wax Pigments DROUGHT YIELD = WU x WUE x HI WUE: Transpiration Efficiency Efficient leaf photosynthesis (CID) Partitioning (HI) Stem carbohydrate storage Water Uptake Ground cover Access to water by roots

20 New lines based on physiological trait (PT) criteria

21 Yield or Biomass (gm -2 ) New PT Line with increased yield & biomass in two distinct drought environments (SOKOLL/3/PASTOR//HXL7573/2*BAU/4/WBLL4//OAX /WBLL1) New PT-SA PT+Land PT+Syn Drt Adap Check 0 YLD-Grav YLD-Drip BM-Grav BM-Drip Gravity irrigation simulates post monsoon drought Drip irrigation simulates Mediterranean drought

22 Canopy Temp (C) & Resid H 2 O (mm) Improved water relations in new PT line New PT-SA PT+Land PT+Syn Drt Adap Check CT-V (Grav) CT-G (Grav) Res H2O cm (Grav) (mm) CT= canopy temperature V=vegetative stage; G=grain-filling CT (Drip)

23 Standard Phenotyping Protocols

24 Thanks for your attention! Wheat Physiology Group- Global Wheat Program