Brar, G.S.

Hucl, P.

Kutcher, R.

English

eCommons@USASK

Stripe rust virulence on Yr genes in Saskatchewan

University of Saskatchewan Research Archive

www.agbio.usask.caStripe rust virulence on Yrgenes in SaskatchewanGurcharn Singh Brar, M.Sc. Plant PathologyPh.D Candidate University of SaskatchewanSoils and Crops- 2017Virulence Surveys• Dr. E.C. Stakman (1914)✓ Variation in degree of incompatibility between host and pathogen✓ Infection types are affected by environmental conditions✓ Sometimes susceptible lines at seedling stage are fairly resistant in field✓ A supposedly resistant variety needs to be evaluated under varying environmental conditions to assess its value of resistanceVirulence Surveys• Host lines includes cultivars, near-isogenic lines, supplemental differentials• Purpose: characterization of isolates into races, frequency and distribution of races• To serve the needs of wheat breeders and growers!!• A gene might behave differently in controlled environment at seedling and in field, e.g. Lr21, Sr21, Sr45Race characterization-indoor• Differentials: Avocet near-isogenic lines carrying YrA, Yr1, Yr5, Yr6, Yr7, Yr8, Yr9, Yr10, Yr15, Yr18, Yr24/26, Yr25, Yr27, Yr28, Yr29, Yr31, Yr32, YrSP, and other differentials carrying YrTye, YrSu, Yr3a, Yr3b, Yr4a, Yr4b, YrTre, Yr43, Yr44, YrExp2, YrPa1, YrPa2, YrPa3, YrMor• Classification of isolates into virulent/avirulent based on a rating scale• Are virulence surveys really informative?Genetic basis of resistance in Canadian cultivars• Seedling resistance genes: Yr7, Yr9, Yr10, Yr17, Yr27• Adult Plant Resistance (APR) genes: Yr18/Lr34, Yr29/Lr46, Yr36 (HTAP)Methodology• Avocet NILs + wheat varieties (CDC Go, CDC Alsask, AC Barrie, Carberry, Lillian, AC Avonlea, AC Interpid, Produra, Paha, Stephens, Yamhill, Moro + Tritcale varieties: AC Certa, Ultima, Pronghorn, Brevis, Bunker• Seeded at 6-8 sites fro 2013-2016• Border of AC Barrie or Avocet S• Disease rating at early milk to soft dough stageResults and discussion• Close association among years✓ Corr. (2013-2014)= 84%✓ Corr. (2014-2016)= 94%✓ Corr. (2013-2016)= 78%• Triticale varieties: all resistant to immune• Yr5, Yr15, YrSP, Yamhill: Resistant• Virulence fixed for: YrA, Yr6, Yr7, Yr8, Yr9, Yr27, Yr29, Yr32, YrSuField evaluation (12 site-years)Brar et al. 2016. unpublished.Yr2, Yr17, Yr28Take home message• Keep regional cultivars in virulence surveys• Partial virulence or partial resistance are important• Indoor experiments should associate with field experiments for virulence surveys• Successful management: deployment of known effective Yr genes in combination (towards achieving durable resistance)AcknowledgementsAcademic & Research SupervisorsDrs. Randy Kutcher and Pierre HuclDean’s Scholarship for PhDGraduate Scholarship for PhD minor scholarships and tons of love from Almighty God, Family, and Friends!!!Agriculture Development FundDevolved Scholarship for M.Sc. 

https://harvest.usask.ca/bitstream/10388/8734/1/G.%20Brar%20et%20al.%2c%202017.pdf

Stripe rust virulence on Yr genes in Saskatchewan

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