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Genetic control of wheat adaption to CA. Richard Trethowan

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A presentation at the WCCA 2011 event in Brisbane.

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Genetic control of wheat adaption to CA. Richard Trethowan

  1. 1. Genetic control of wheat adaptation to conservation agricultureRichard Trethowan, Tariq Mahmood, Zulfiqar Ali, Klaus Oldach
  2. 2. Implications of breeding crops adapted to conservation tillage• New diseases (tan spot, root rots etc)• More challenging seed bed• Weed competition• Changes in nitrogen management (N-use efficiency)• Tillage x cultivar interaction
  3. 3. Published examinations of genotype x tillage interactionsCrop Genotype Literature x TillageWheat +/- Gutierrez (2005); Cox (1991)Barley - Ullrich & Muir (1986)Sorghum - Francis et al. (1985)Maize +/- Newhouse (1985); Brakke et al (1983); Newhouse & Crosbie (1983)Rice - Melo et al (2005)Soybean - Elmore (1990); Pfeiffer (1987)Pulses ? NA
  4. 4. Gutierrez (2005):Genotype x tillage study in wheat in MexicoDiverse set of wheat cultivars:Berkut, Sokoll, Kambara, Weebill 1, Rebeca F20006, Romoga F96, Nahuatl F2000, Juchi F2000, Temporalera M87, Tlaxcala F2000Diverse environments:Irrigated & rainfed over two years
  5. 5. Analysis of variance; El Batan 2003 and 2004 – rainfed (Gutierrez, 2005) Mixograph Yield Biomass TKW P% SDS Height Mixing Stability timeYear ** ** ** ** ** ns ns **Tillage ** ** ns ns ** * * nsCultivar ** ** ** ** ** ** ** **Cultivar x Year ** ** ** ** ** ** ** **Cultivar x ** * ** ** ** ns ns **TillageCultivar x Till x ns ns ** ns * ns ns nsYear
  6. 6. Wheat grain yield for different tillage and planting methods at El Batan (Mexico) over 2 years 2500 2000 Yield kg/ha 1500 1000 500 a b b b 0 ZT flat ZT beds CT flat CT beds ZT = zero tillage; CT conventional tillage
  7. 7. Yield of a common set of 50 genotypes undercontrasting tillage regimes in Australia and Mexico over 2 years • Higher yields under 7000 zero-till Mexico 6000 • No significantYield kg/ha 5000 genotype x tillage Australia interaction in Mexico 4000 (NS) 3000 2000 1000 Zero Till 2 7 2 7 2 8 2 8 2 7 2 7 2 8 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Comp 2 Till Source: Trethowan & Manes
  8. 8. Can a genotype x tillage interaction be designed? Five crosses among lines with contrasting responses under zero- tillageAlways selected under Always selected underzero-tillage alternating conventional tillage between rainfed and alternating between rainfed irrigated conditions and irrigated conditions Advanced lines from both selection regimes evaluated under both zero and conventional tillage Sayre & Trethowan
  9. 9. Effects of Cross and Selection System on Grain Yield Averaged over 2005, 2006 and 2007 Cross x Selection System LSD (0.05) = 143 kg/ha 6400 6200Grain yield (kg/ha) 6000 5800 5600 5400 5200 a b a b a a a a a a 5000 SERI/..BERKUT SW94.../PBW65 FILIN./PASTOR MILAN./PASTOR PFAU../AMAD Cross ZERO TILL SELECTION CONV TILL SELECTION
  10. 10. Genetic variability forimproved adaptation toconservation agriculture
  11. 11. Traits important in crop emergence & establishmentTrait Recent evidenceColeoptile length Trethowan et al (2001); Rebetzke et al (2004 & 2007); Erayman et al (2006)Coleoptile thickness Rebetzke et al (2004)Emergence from depth Trethowan et al (2005); Joshi et al (2007)Rapid height growth Olesen et al (2004)Seedling vigour Liang and Richards (1999); Trethowan et al (2005); Erayman et al (2006)Kernel weight & embryo size Liang and Richards (1999)Faster stubble decomposition Joshi et al (2007)Weed suppression & Allelopathy Olesen et al (2004); Bertholdsson, 2005Early biomass/specific leaf area Liang and Richards (1999); Olesen et al (2004)Deeper roots Reynolds and Trethowan (2007)N-use efficiency Van Ginkel et al (2001); Trethowan et al (2005)Disease resistance Trethowan et al (2005); Joshi et al (2007)Seedling temperature tolerance Boubaker & Yamada (1991); Dell’Aquila and Spada (1994)
  12. 12. Useful sources of genetic variability in wheat + • Cultivars released in areas where farmers have adopted CA • Hexaploid primary synthetics AB D • LandracesT. durum A. tauschii • Translocations from wild relatives • Alternative dwarfing genes • Sources of resistance to foliar blights and root rots ABD
  13. 13. Effect of different height reducing genes on coleoptile length in wheatRht gene GA insensitive GA sensitive (-) coleoptile (+) coleoptileRht-B1b XRht-D1b XRht 7 XRht 8 XRht 9 XRht 12 XSource: Rebetzke et al 2004. 2007
  14. 14. Genotype x tillage practice trials on two soil types atNarrabri:Berkut/Krichauff mapping population (160 lines)
  15. 15. Mean yield across tillage regimes, years and soil types at NarrabriTillage Zero till Conven till P<regimeHeading (days) 108.5 a 109.1 b 0.05Yield (kg/ha) 1702 a 1368 b 0.001Soil type Grey vertisol Red kandosolHeading (days) 109 a 108.6 a nsYield (kg/ha) 1733 a 1337 b 0.001
  16. 16. The yield difference between zero-tillage (ZT) andconventional tillage (CT): means based on 2 sites in 2 years. 800 Yield difference kg/ha (ZT-CT) 600 Krichauff 400 200 Berkut 0 0 20 40 60 80 100 120 140 160 -200 -400 -600 Genotype
  17. 17. Significant QTL effects for yield under contrasting tillage regimes on two soil types in 2 yearsChr Interval Treatment Soil type Additive Allele effect %1B gwm268/wPt-3475 CT Grey v 8 K1B wPt-1313/gmw140 CT Grey v 10 K1D cdf19/wmc216 CT Red k 10 K2D wPt-3728/cfd44 ZT Grey v 9 K2D gmw484/wmc27 ZT Red k 9 B5A cfa2155/wPt1370 ZT Grey v 25 B5A cfa2115/wPt1370 CT Grey v 14 B5A cfa2115/wPt1370 CT Red k 9 B5B wmc99/wPt2373 ZT Grey v 12 B
  18. 18. Select diverse germplasm & screen for response to tillage measuringyield, disease and product quality to determine the extent of genotype x tillage interactions. Combine in crosses Identify parents with with emphasis on extreme trait adaptation to the expression. Include target conditions & parents with QTLs complementary QTLs Implement a selection Evaluate fixed lines strategy. Eg combine across a range of deep planting in a zero- conservation agricultural tillage system with practices in multi- disease inoculation & locational trials in the marker assisted sel. target region. Select lines with high yield, appropriate quality and stable performance across farmer practices within the target region for release.
  19. 19. Acknowledgments:CIMMYT – Yann Manes/Ken Sayre/Bram GovaertsSARDI – Klaus Oldach, Hugh WallworkTeam at PBI Sydney & NarrabriMolecular Plant Breeding CRC

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