Carmel Bud Failure. HAL Project AL Dr Prue McMichael Dr Kate Delaporte ABA & Trial Co-operators

Transcription

1 Carmel Bud Failure HAL Project AL08015 Dr Prue McMichael Dr Kate Delaporte ABA & Trial Co-operators

2 Tufted growth at end of bare shoots Bare shoots, no nuts Dark Lines around buds Slide 2

3 Visual Rating of Damage 1 = healthy green bud, 0% browning 1x = healthy green bud; with possible lignification inside bud, but not at bud heart, usually tip section, 0% browning DC = bud heart is dead but still present D = entire bud dead but still present Slide 3

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6 Bud Dissection Results Spring 2009 External bud appearance not indicative Spring bud viability predicted in previous autumn Damaged buds do not recover Affected and non-affected trees have some damaged buds Bare wood laterals have most damaged buds Vegetative and floral buds may display bud failure Central buds (mostly vegetative) from affected trees, have most damage Damaged/dead buds still attached Monash buds - High percentage of healthy buds Monash buds - High proportion of floral buds Slide 6

7 Bud Transformation to Floral Buds May-June 2009 Region Status Outside Buds (combined) Riverland Affected 47% Riverland Non affected 68% MIA Affected 3% MIA Non affected 74% Slide 7

8 Summary 2008/2009 Only Carmel affected No recovery from 2008 onset affected trees *No new bud failure in non-affected trees Damaged vegetative buds don t leaf out *Damaged floral buds delayed flowering or no flowering Young affected trees with up to 90% canopy affected Severely affected trees low nut load Heavy pruning has not reversed situation Temperatures in March 2008, January extreme Slide 8

9 2009/10 Investigations Followed trees in one orchard Started bud dissections in late November Continued to review temperatures Slide 9

10 Central Bud Status Season Percent (%) Healthy Flow er Initiation <50% damage >50% damage Missing Dead Jan-10 Feb-10 Mar-10 Apr-10 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 ABA Mar 10 MONASH AFFECTED NON AFFECTED Slide 10

11 Central Bud Comparison March 2009 & 2010 March 2009 Bud status (% buds) Riverland Orchard 2 Monash Affected Non-affected budwood Healthy buds <50% damage > 50% damage Dead March 2010 Healthy buds <50% damage > 50% damage Dead Slide 11

12 Key Observations 2010 By January 2010 Damaged buds in affected AND non-affected trees By March 2010 Leaf out predictions problems in both November 2009 heatwave contributed? Slide 12

13 Regional High Temperature Exposure (DD > 27 C) Spring-early summer Accumulated DD >27 C Location ( October 1- December 31) Average? yr 10-yr California 180 Griffith Mildura Renmark Slide 13

14 Regional Extreme (> 35 C) Heat Events Spring-early summer Location Days with maximum >35 C (October 1- December 31) Average yr 10-yr Griffith Mildura Renmark Slide 14

15 Extreme (> 35 C) Seasonal Exposures (Oct-March) Location Growing season days (total) with maximum >35 C Average 2005/ / / / /10 4-yr 10-yr Griffith Mildura Renmark Slide 15

16 Technical Knowledge Non-infectious bud failure California Bud failure potential: genetic, inherited Varies bud to bud on shoots Progressive, persistent Increases with successive generations Increases once planted

17 Technical Knowledge (cont d) Bud failure onset: interactions, variable high temperatures DD >27 C annual growth Severity and rate; bud failure potential age of onset % canopy affected seasonal temperatures

18 Technical Knowledge (cont d) Bud failure patterns: growth management reflect bud failure at planting bud source & cutting time budding time Temperatures yield vs veg effects

19 Practical Responses - Nurseries Know budwood sources, cutting strategy Use only basal buds, low shoots, spring Understand temperature effects; hot autumn - floral, veg buds affected hot spring - veg buds affected 1 flush vs 2 flushes Seek grower feedback number of affected trees, onset age

20 Practical Responses - Growers Assess impacts Record onset, tree age, % canopy Options; Remove Block viability Top-work; Affected bud on non-affected tree NBF Good bud on affected tree OK Check Non-pareils Traceable budwood ask nursery

21 Practical Responses - Industry New Carmel, Non-pareil clones Find oldest Carmel orchard trees System for Monash and nursery bud traceability ID high and low bud failure potential source trees Evaluation include bud failure, regional, new pollinators

22 Why now in Australia? Successive generations? 2 flushes autumn cuts? High temperatures autumn 2008, spring 2009 Unknown budwood sources