Carmel Bud Failure HAL Project AL08015 Dr Prue McMichael Dr Kate Delaporte ABA & Trial Co-operators
Tufted growth at end of bare shoots Bare shoots, no nuts Dark Lines around buds Slide 2
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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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
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
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 2009 - extreme Slide 8
2009/10 Investigations Followed trees in one orchard Started bud dissections in late November Continued to review temperatures Slide 9
Central Bud Status Season 2010 100 90 95 87 80 79 82 77 70 66 Percent (%) 60 50 57 59 48 Healthy Flow er Initiation <50% damage >50% damage 40 40 44 39 Missing Dead 30 30 20 20 23 22 10 16 13 13 9 11 12 15 9 0 5 0 1 1 0 0 0 0 0 2 5 0 0 1 0 0 0 1 1 1 0 1 1 0 0 1 2 0 2 1 0 0 1 0 4 0 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
Central Bud Comparison March 2009 & 2010 March 2009 Bud status (% buds) Riverland Orchard 2 Monash Affected Non-affected budwood Healthy buds 79 98 97 <50% damage 20 1 1 > 50% damage 1 0 0 Dead 0 0 0 March 2010 Healthy buds 13 59 95 <50% damage 66 39 1 > 50% damage 13 1 0 Dead 0 0 0 Slide 11
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
Regional High Temperature Exposure (DD > 27 C) Spring-early summer Accumulated DD >27 C Location ( October 1- December 31) Average? 2007 2008 2009 4-yr 10-yr California 180 Griffith 151 108 209 143 128 Mildura 173 97 202 138 129 Renmark 193 110 210 155 140 Slide 13
Regional Extreme (> 35 C) Heat Events Spring-early summer Location Days with maximum >35 C (October 1- December 31) Average 2005 2006 2007 2008 2009 4-yr 10-yr Griffith 12 22 16 8 21 15 13 Mildura 12 15 18 8 27 13 12 Renmark 14 19 22 9 26 16 14 Slide 14
Extreme (> 35 C) Seasonal Exposures (Oct-March) Location Growing season days (total) with maximum >35 C Average 2005/06 2006/07 2007/08 2008/09 2009/10 4-yr 10-yr Griffith 55 58 47 36 43 49 41 Mildura 40 43 49 35 56 42 38 Renmark 45 47 57 38 57 47 42 Slide 15
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
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
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
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
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
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
Why now in Australia? Successive generations? 2 flushes autumn cuts? High temperatures autumn 2008, spring 2009 Unknown budwood sources