Blackleg resistance in Canola; its breakdown and latest strategies being adopted in Australia to manage the disease

Transcription

1 Blackleg resistance in Canola; its breakdown and latest strategies being adopted in Australia to manage the disease Andrew Easton Crop Research Lead Brassicas. Pacific Seeds, Toowoomba Qld Australia.

2 Blackleg Disease Lifecycle Factors affecting disease severity Types of resistance Disease screening methodology Blackleg Management Guide Blackleg resistance ratings and groupings

3 Blackleg Life Cycle Source: Canola Ute Guide

4 Blackleg Seedling Symptoms Pycnidia Constriction at base of cotyledons

5 Blackleg Adult Plant Symptoms Cankering at plant base Death from flowering onwards

6 Yield (kg/ha) Yield Under High Blackleg Pressure Bordertown Hyola 60 Surpass 603CL Oscar Rainbow Charlton Source: S4 trial Data (2001)

7 Stubble Weight (kg/ha) Effect of Time on Stubble Weight Stubble Age (Months) Source: Marcroft (2002)

8 Ascospores/ha Effect of Time and Rainfall on Ascospore Release 600,000, ,000, ,000, ,000, ,000, ,000,000 0 Low Rainfall Medium Rainfall High Rainfall One Two Three Four Stubble Age (Yrs) Source: Marcroft, S. DPI Vic. Average of low, med and high rainfall sites 2000/2001 data

9 Median & >80% CSII Effect of Distance on Disease Incidence Distance to 6-month old stubble (m) Source: Marcroft, S. DPI Vic. Average of low, med and high rainfall sites 2000/2001 data

10 Effect of Stubble Management on Ascospore Discharge Stubble Age (Months) Stubble Treatment Stubble Wt (kg/ha) Ascospore Discharge/ha Conserved ,896,000 Destroyed ,888,000 Conserved 108 2,463,000 Destroyed ,000 Conserved 29 13,000 Destroyed 26 11,000 Source: Marcroft, S. DPI Vic. Lake Bolac 2000/2001 data

11 Types of Resistance There are two types of resistance for Blackleg Qualitative or seedling stage resistance Quantitative or adult-stage resistance To date thirteen major resistance genes have been reported B. napus = Rlm1, Rlm2, Rlm3, Rlm4, Rlm7 and Rlm9 B. rapa = Rlm8 B. rapa subsp. sylvestris = LepR1, LepR2, LepR3 & LepR4 B. juncea = Rlm5 and Rlm6

12 Types of Resistance There are two types of resistance for Blackleg Qualitative or seedling stage resistance Quantitative or adult-stage resistance To date thirteen major resistance genes have been reported B. napus = Rlm1, Rlm2, Rlm3, Rlm4, Rlm7 and Rlm9 B. rapa = Rlm8 B. rapa subsp. sylvestris = LepR1, LepR2, LepR3 & LepR4 B. juncea = Rlm5 and Rlm6

13 Why is Blackleg Such a Successful Pathogen? Large inoculum loads present in crop stubble Sexual reproduction on stubble Extremely large populations of genetically diverse wind-borne recombinant ascospores Prolific asexual spore production Populations readily adapt to selection pressure from extensive sowing of cultivars with same resistance genes Rapid virulent isolate frequency increases Resistance Breakdown Howlett (2014) Canola Pathology Workshop

14 Surpass 400 Cummins 2002

15 Cummins 2003 Tornado TT Surpass 400

16 Cropping History Ivan Schultz Surpass 603CL Pasture Wheat Barley Canola - Surpass 603CL Surpass 603CL Peas & Volunteer Canola Lucerne & Volunteer Canola NORTH

17 Single Spore Isolate Screening Methodology Growing L maculans single spore isolate on agar plate

18 Single Spore Isolate Screening Methodology

19 Stubble Type Screening Methodology

20 Assessing Adult Plant Resistance Score =0 0% Score =1 Score =2 1-10% Score =4 Score = % 50-75% %

21 Variety Effect on Blackleg Population Dynamics. Rlm1 Rlm4 Virulent Avirulent Avirulent Virulent Virulent Avirulent Avirulent Avirulent Source: Van de Wouw (2014) Pathology Workshop

22 Blackleg Management Guide Step 1 Source: GRDC 2014 Blackleg Management Guide Fact Sheet

23 Blackleg Management Guide Step 2 Source: GRDC 2014 Blackleg Management Guide Fact Sheet

24 Blackleg Management Guide Step 3 Source: GRDC 2014 Blackleg Management Guide Fact Sheet

25 Blackleg Management Guide Step 3 Source: GRDC 2014 Blackleg Management Guide Fact Sheet

26 Blackleg Management Guide Step 3 Source: GRDC 2014 Blackleg Management Guide Fact Sheet

27 R NATIONAL 2013 CONVENTIONAL CAA BLACKLEG RATINGS R R-MR R-MR MR MR MR (P) MR-MS MS-S S Source: GRDC 2013 Blackleg Management Guide Fact Sheet

28 HYOLA 575CL HYOLA 474CL HYOLA 971CL 43Y85 43C80 44C79 45Y82 CARBINE ARCHER 44Y84 45Y86 R NATIONAL 2013 CLEARFIELD TECHNOLOGY CAA BLACKLEG RATINGS R MR (P) MR MR - MS MS MS MS (P) MS MS-S MS-S (P) Source: GRDC 2013 Blackleg Management Guide Fact Sheet

29 NATIONAL 2013 HYBRID TRIAZINE TECHNOLOGY CAA CANOLA BLACKLEG RATINGS R (P) R R (P) R-MR (P) MS (P) MS-S MS-S S S (P) HYOLA 656TT HYOLA 555TT HYOLA 450TT HYOLA 559TT CB ATOMIC HT CB HENTY HT CB JARDEE HT CB JUNEE HT CB NITRO HT Source: GRDC 2013 Blackleg Management Guide Fact Sheet

30 HYOLA 400RR VT535G HYOLA 500RR HYOLA 505RR HYOLA 404RR CB FRONTIER RR NUSEED GT50 NUSEED GT41 GT COBRA 43Y23 GT VIPER VICTORY V5002RR 45Y22 Source: GRDC 2013 Blackleg Management Guide Fact Sheet MONOLA 513GT CB STATUS RR CB ECLIPSE RR R NATIONAL 2013 RR TECHNOLOGY - CAA BLACKLEG RATINGS R (P) R R R R R-MR R-MR (P) R-MR R-MR (P) MR MR MR MR S S

31 Hyola Blackleg Information Resistance Rating Resistance Group Hyola 401 VS - Hyola 50 R AD Hyola 61 MR C? Hyola 76 R AD Hyola 433 R D Hyola 571CL R B,F? Source: GRDC Blackleg Management Guide Fact Sheet

32 Blackleg Summary Fungal disease which can be devastating Cool showery conditions favour disease Severity affected by numerous factors Age of stubble Rainfall Proximity of crop to stubble Stubble management practices Rotation History Genetic Resistance Seedling and adult plant resistance mechanisms Hyola hybrids have best resistance available