Worksho op on Plant Bioregulators for Pome and Stone Fru it Production Okanagan Packing house Fieldmans Sping Meetin ng, Kelowna Febru uary 7, 2008 John A. Cline e, Associate Professor Department t of Plant Agriculture Univer rsity of Guelph jcline@ @uoguelph.ca www.plant.u uoguelph.ca/treefruit
Bioregulators Use ed In Tree Fruits Feb 7 2008 2
Natural Plant Growt th Substances 1. Gibberellins involved in flow wering, cell elongation, dormancy, delay senescence, induce maleness in dioecious flowers 2. Auxins apical dominance, ripening, flowering 3. Cytokinins i stimulate t cell division, i growth of lateral l buds 4. Ethylene - release of dormancy, stimulates leaf and fruit abscission, induction of femaleness in dioecious flowers, stimulates flower and leaf senescence, stimulates fruit ripening. 5. Abscisic Acid dormancy, w ater stress Reference http://www.plant-hormones.info/index.htm Feb 7 2008 3
unction Products Available. Inhibit Flowering GA 3, GA 4, GA. Promote Flowering Ethrel, NAA. Influence fruit ripening GA 3, GA 4, GA 7, Ethrel, Cherries, Apples, Peach and quality Retain. Fruit thinning Carbaryl*, NAA, BA, Surfactants, t Ehtrel Apple, Peach. Influence ethylene Ethrel, MCP, ReTain Apple, Peach synthesis. Fruit finish GA, Koalin Clay* Apple,. Change fruit shape Benzyl adenine (BA). Reduce Preharvest drop. Reduce Vegetative growth NAA, ReTain Apogee Research Experience Feb 7 2008 4 - these products are not plant growth regulators A 7 Apples, Peaches, Cherries Apple Apple Apple, Peach Apple, Peach
Chemical Thinning Principles of Chemical Thinning Pr oducts used on Ontario Thinning with Maxcel Feb 7 2008 5
Fruit size Improved crop value Market requirement Benefits of Thinning Harvest efficiency Return bloom Reduce biennial bearing Disadvantages Yield reduction Greater propensity to fruit nutritional problems Feb 7 2008
Economics of Thinning Fruit trees often require only 5-10% of fruit to set a commercial crop Crop Value Fruit per tree Fruit size Quality Feb 7 2008 7
Registered Chemical Thinners for Apples in Can nada 1. Fruitone N (NAA) 2. Carbaryl (Sevin XLR+) 3. 6-BA (Accel/Maxcel) Feb 7 2008 8
Results from Chemical Thinning are not alw ways predictable Feb 7 2008
Hand Thinning Least Desirable Feb 7 2008 10
Suggested products and rates for chemical thinning various cultivars Feb 7 2008 11
Cultivar Sensitivity to Chemical Thinners Easy to Thin Braeburn Crispin Ginger Gold Idared Jerseymac Jonagold Jonathan Red Del Ambrosia Honeycrisp Intermediate to Thin Cortland Empire Jonamac McIntosh Nothern Spy Gala Difficult to Thin Fuji Golden Delicious Lodi Rome Spartan Spur Red Delicious Wealthy Feb 7 2008 12
Thinning Products and Rates of Activity NAA (ppm) Accel (ppm) Sevin Accel + Sevin NAA+Sevin (L/ha) (ppm, L/ha) (ppm, L/ha) Mild 5 50 Moderate 10 75 Aggressive 15-1.0-15 1.5 50, 0.5 5, 0.5-75, 1.0 10-15, 1.0 Feb 7 2008
Table 1. Tray pack size of apples in relatio on to number of apples per bin and per tree Min size Min No. apples required ray Size in mm Wt (g) to fill bin 1 30 196 2 1/4 57.0 102 3920 235 175 2 3/8 60.0 114 3500 210 163 2 1/2 64.0 123 3260 196 150 25/8 67.0 133 3000 180 138 2 3/4 70.0 145 2760 166 125 2 7/8 73.0 160 2500 150 113 3 76.0 177 2260 136 100 31/8 79.0 200 2000 120 88 3 1/4 83.0 227 1760 106 80 3 3/8 84.5 250 1600 96 72 3 1/2 89.0 278 1440 86 64 3 5/8 92.0 313 1280 77-20 bushel bin capacity Number of 500 apples required per tree for given tree density, desired yield and fruit size Density (trees/acre) 2 1000 2000 Projected yield (Bins/ac) 40 40 50 40 50 314 157 196 78 98 280 140 175 70 88 261 130 163 65 82 240 120 150 60 75 221 110 138 55 69 200 100 125 50 63 181 90 113 45 57 160 80 100 40 50 141 70 88 35 44 128 64 80 32 40 115 58 72 29 36 102 51 64 26 32 - Trees spaced at 6.5' x 13' (500 trees/acre; vertical axe type system), 3.5' x 12' (1000 trees/acre; spindle system), and ' x 10' (2000 trees/acre; super spindle system), Avoid Target Feb 7 2008 14
Tim ing NAD - Amidthin (King Bloom petal fall) Accel 8-12 mm Sevin XLR - Petal Fall - 21 Days after Full Bloom NAA - Bloom - 12 mm (later ap pplications tend to reduce fruit size) apply prior to warming trends as increasing temperatures promote the thinning response Bright sunny days following applications tend to decrease the thinning respon nse Higher night temperatures increase the thinning response Feb 7 2008
Water Volume of water and dspray Distribution tib ti Apply sufficient water to obtain good foliage and fruitlet coverage. Do not concentrate beyond 2X or 1000 litres per hecta re Apply 65-90 % of water volume to the top of thetree canopy (except super spindle) Feb 7 2008
Blossom Thinning Not widely adopted in Ontario. ATS works but often causes phytot oxicity Feb 7 2008 17
Advances in Bloss som Products Ammonium thiosulphate (ATS) is effective, but remains unregistered, not certified organic Other natural compounds an nd surfactants being tested Likely adopted commerciallyin combination with a fruitlet thinning program Phytotoxicity and risk of frost major barriers Feb 7 2008 18
Thinning Gala with Maxcel Maxcel Adequately thinned Improved fruit size beyond effect of hand thinning Worked effectively with Sevin Table 5. Effect of Maxcell on yield, fruit number and fruit size of 'Gala'/M.26 apple trees. University of Guelph, Simcoe, Ontario, 2004. Total number Mean fruit Crop Rate Yield fruit per weight density Treatment Untreated Control Hand th hinned control (mg/l) (kg.tree -1 ) 36.0 30.5 tree 229 167 (g) 158.6 182.3 (#.cm -2 ) 7.1 5.9 Maxcel 75 33.6 183 184.9 5.5 Maxcel 100 23.8 134 178.7 4.6 Maxcel + Carbaryl x 75 23.7 127 188.2 4.1 NAA + Carbaryl x 5 23.3 120 198.1 4.3 significa ance z *** *** *** *** LSD (P=0.05) 3.85 23.7 12.81 1.15 P value <0.0001 <0.0001 <0.0001 <0.0001 x Carbaryl XLR Plus applied at 750 ppm z ns, ***, **, *, indicates non significance and statistical significance at P=0.001, P=0.01, and P=0.05, respectively Feb 7 2008 19
Thinning Gala w ith MaxCel (BA) Adequately thinned Improved fruit size beyond effect of hand thinning Worked effectively with Sevin Table 3. Effect of Maxcel and Carbaryl on yield, fruit number and fruit size on 10-yr-old 'Royal Gala'/Bud.9 apple trees. University of Guelph, Simcoe, Ontario, 2007. TCSA Mean Total fall Yield fruit Crop number 2007 Yield efficiency weight density Rate fruit per Treatment (mg/l) (cm 2 ) (kg.tree -1 ) (kg.cm 2 ) tree (g) (#.cm -2 ) Untreated Control 41.2 25.0 0.61 187.5 137.4 4.3 Hand thinned control (every other spur) 43.0 20.7 0.49 131.9 160.3 3.2 Maxcel 75 37.4 23.8 065 0.65 186.9 137.9 53 5.3 Maxcel 100 45.4 28.9 0.65 186.8 156.1 4.2 Maxcel + Carbaryl 75,750 41.3 15.9 0.40 94.3 175.6 2.4 Maxcel + Carbaryl 100,750 40.3 14.6 0.45 81.1 188.1 2.5 Exilis 75 46.0 33.0 0.72 229.8 146.6 5.0 Exilis 100 38.6 24.4 0.66 175.9 144.3 4.8 Eili Exilis + Carbaryl Exilis + Carbaryl significance z LSD (P=0.05) P value 75, 1000 43.9 16.9 036 0.36 107.4 168.3 24 2.4 100, 1000 41.3 13.6 0.32 87.9 174.2 2.1 ns ** * *** *** ** 7.74 9.83 0.25 75.42 23.25 1.98 0.4294 0.0012 0.0155 0.0004 <0.0001 0.0030 z ns, ***, **, *, indicates non significance and statistical significance at P=0.001, P=0.01, and P=0.05, respectively Feb 7 2008 20
Effect of 6-BA and Carba aryl on Gala Crop Load 9 8 Cro op load (# cm -2 ) 7 6 5 4 3 2 1 0 Control Hand thinned 75 mg/l 6- BA 100 mg/l 6-BA 75 mg/l 6-BA + Carbaryl 100 mg/l 6-BA + Carbaryl 5 mg/l NAA + Carbaryl Feb 7 2008 21
Effect of 6-BA and Carbaryl on Gala Yield and Fruit Size Yield (kg tree -1 ) 40 35 30 25 20 15 10 5 Yield Fruit weight 250 200 150 100 50 Me ean fruit we eight (g) 0 Control Hand 75 mg/l 100 mg/l 75 mg/l 100 mg/l 5 mg/l thinned 6-BA 6-BA 6-BA + 6-BA + NAA + Carbaryl Carbaryl Carbaryl 0 Feb 7 2008 22
Thinning Resourc ces Updated Thinning Information Cultivar Sensitivity Table of Contents Feb 7 2008 23
unction Products Available. Inhibit Flowering GA 3, GA 4, GA. Promote Flowering Ethrel, NAA. Influence fruit ripening GA 3, GA 4, GA 7, Ethrel, Cherries, Apples, Peach and quality Retain. Fruit thinning Carbaryl*, NAA, BA, Surfactants, t Apple, Peach. Influence ethylene Ethrel, MCP, ReTain Apple, Peach synthesis. Fruit finish GA, Koalin Clay* Apple,. Change fruit shape Benzyl adenine (BA). Reduce Preharvest drop. Reduce Vegetative growth NAA, ReTain Apogee Research Experience Feb 7 2008 24 - these products are not plant growth regulators A 7 Apples, Peaches, Cherries Apple Apple Apple, Peach Apple, Peach
Gibberellin-Based Growth Regulators Products: Activol/Progibb and Promalin 1. Apple - Reduce russeting (G. Delicious) - Mixture of GA 4+7 - Improve fruit quality 2. Improve apple size and shape - used on Red Delicious for typiness - effective on Royal Gala Feb 7 2008 25
unction Products Available. Inhibit Flowering GA 3, GA 4, GA. Promote Flowering Ethrel, NAA. Influence fruit ripening GA 3, GA 4, GA 7, Ethrel, Cherries, Apples, Peach and quality Retain. Fruit thinning Carbaryl*, NAA, BA, Surfactants, t Apple, Peach. Influence ethylene Ethrel, MCP, ReTain Apple, Peach synthesis. Fruit finish GA, Koalin Clay* Apple,. Change fruit shape Benzyl adenine (BA). Reduce Preharvest drop. Reduce Vegetative growth NAA, ReTain Apogee Research Experience Feb 7 2008 26 - these products are not plant growth regulators A 7 Apples, Peaches, Cherries Apple Apple Apple, Peach Apple, Peach
Ethylene Relate d Bioregulators Ethephon, Aminoethoxyvinylglycine Ethephon (Ethrel) liquid compound that dispenses C 2 H 2 accelerate ripening at harvest (use cautiously) Can use on non-bearing trees to enhance flowering the following year Feb 7 2008 27
Gibberellic Acid for Sweet Cherries - preharvest sprays exten d harvest season of cherries -larger firmer fruit, less bruising g(pitting) in storage - used widely in industry Feb 7 2008 28
Objectives To determine the benefits of GA 3 on: 1. Fruit size 2. Fruit firmness 3. Fruit maturity (harvest) 4. Rain-cracking Timing Jun 12 Secondary objectives were to investigate: Jun 20 1. Application timing 2. Product formulation (Progibb 4 and Progibb 40%) Feb 7 2008
Methodology A series of experiments conducted (2002-2007) 2007) Rates: 20-80 mg/l GA 3 (Progibb 40%) Air blast applications Single trees Fruit quality measurements included: fruit firmness, surface colour, soluble solids, fruit weight, and rain-inducedd fruit cracking Feb 7 2008 30
Flesh firmness was measured on 25-5050 fruit, 2 sides Fruit texture Analyzer Model GS-14, GÜSS, South Africa 3 mm probe, depth of 1mm (did not penetrate skin) Feb 7 2008
Table 1. Effect of giberillic acid treatment on fruit colour and firmness of 'Hedelfingen' cherries. Vineland, 2007. A 3 (mg/l) Timing Fomulation ntreated - - 0 straw colour Progibb 40% 0 straw colour Progibb 40% 0 straw colour Progibb 40% 0 10 prior to straw colour Progibb 40% 0 straw colour + 10 days prior Progibb 40% 0 straw colour Progibb 4% 0 straw colour Progibb 4% ignificance z SD (p=0.05) value ntreated - - 0 straw colour Progibb 40% 0 straw colour Progibb 40% 0 straw colour Progibb 40% 0 10 prior to straw colour Progibb 40% 0 straw colour + 10 days prior Progibb 40% 0 straw colour Progibb 4% 0 straw colour Progibb 4% ignificanceifi z SD (p=0.05) Feb 7 2008 32 value 3 mm probe Firmnes s (kg) z Colour L value (lightness) 1st pick (July 11) Mean fruit weight (g) Brix ( o ) 0.16 c 31.5 d 7.6 16.3 0.18 b 34.7 b 7.5 17.8 0.19 a 34.5 b 7.7 17.9 0.20 a 35.3 a 6.3 16.2 0.18 b 33.5 c 7.3 17.0 0.17 b 34.8 ab 6.9 15.9 0.17 b 33.0 c 7.3 17.1 018 0.18 b 35.0 ab 63 6.3 16.0 *** *** ns ns 0.01 0.5 2.8 2.0 < 0.0001 < 0.0001 0.7524 0.7112 2nd pick (July 18) 0.10 e 31.0 d 8.9 abc 17.1 0.18 a 31.3 d 10.0 a 15.0 0.17 a 32.1 bc 8.2 bcd 18.6 0.16 b 32.3 bc 8.8 abc 16.7 0.13 d 32.4 b 9.3 ab 18.8 0.14 c 33.2 a 7.9 bcd 15.9 0.13 d 31.8 c 7.7 cd 17.3 0.12 d 33.2 a 7.0 d 14.4 *** *** * ns 0.01 0.5 1.6 3.3 < 0.0001 < 0.0001 0.0154 0.1115
Summary of GA effects Progibb has consistently increased fruit firmness and had a slight effect on fruit colour (harvest) Inconsistent treatment effects on fruit weight, and rain cracking Progibb 40% was more effective than Progibb 4% in enhancing fruit firmness and size Feb 7 2008
unction Products Available. Inhibit Flowering GA 3, GA 4, GA. Promote Flowering Ethrel, NAA. Influence fruit ripening GA 3, GA 4, GA 7, Ethrel, Cherries, Apples, Peach and quality Retain. Fruit thinning Carbaryl*, NAA, BA, Surfactants, t Apple, Peach. Influence ethylene Ethrel, MCP, ReTain Apple, Peach synthesis. Fruit finish GA, Koalin Clay* Apple,. Change fruit shape Benzyl adenine (BA). Reduce Preharvest drop. Reduce Vegetative growth NAA, ReTain Apogee Research Experience Feb 7 2008 34 - these products are not plant growth regulators A 7 Apples, Peaches, Cherries Apple Apple Apple, Peach Apple, Peach
PBRs to Enhan nce Flowering Ethrel (Ethephon) 150 mg/l NAA (Fruitone-N) 5 mg/l Have been used independently at low concentrations during June-July to enhance return bloom the following season Feb 7 2008 35
Flower Induction & De evelopment Induction 2-6 weeks after full bloom Development 6 wks to bloom following year Most floral parts are present by harvest Feb 7 2008 36
Ethrel on Non Bearing Trees Ethrel sprays can successfully be used to enhance the return bloom of non-bearing Higher rates can be us sed since there is no concern of excessive fruit thinning. Single applications (ea arly July) between 1000-1500 mg. litre -1 Ethrel are as effective as split applications at 50% of these rates. A reduction in tree growth can be expected in the season of application. Feb 7 2008 37
Ethrel on Be earing Trees Lower rates of 150 or 300 mg. litre -1 significantly improved the return bloom of Empire and Fuji, respectively. At least two applications (early July, 1 wk apart) are required to obtain this benefit. Three sprays of NAA at 4 mg. litre -1 was effective for enhancing the return bloom of Empire but not Fuji or Jonagold. Feb 7 2008 38
Feb 7 2008 39
unction Products Available. Inhibit Flowering GA 3, GA 4, GA. Promote Flowering Ethrel, NAA. Influence fruit ripening GA 3, GA 4, GA 7, Ethrel, Cherries, Apples, Peach and quality Retain. Fruit thinning Carbaryl*, NAA, BA, Surfactants, t Ehtrel Apple, Peach. Influence ethylene Ethrel, MCP, ReTain Apple, Peach synthesis. Fruit finish GA, Koalin Clay* Apple,. Change fruit shape Benzyl adenine (BA). Reduce Preharvest drop. Reduce Vegetative growth NAA, ReTain Apogee Research Experience Feb 7 2008 40 - these products are not plant growth regulators A 7 Apples, Peaches, Cherries Apple Apple Apple, Peach Apple, Peach
Why stone fruit tre ees need thinning? Produce an abundance of flowers, of which ~10% are required to produce a full crop to maximize crop value by optimizing fruit size and quality maintain tree growth and structure Feb 7 2008 41
Most Promising Methods to Thin Peac ches Blossom thinning (TMN- -6, Entry) Fruitlet thinning (Ehtrel) Flower inhibition (GA 3 ) Fall applications of ethephon (delays bloom and reduces flowering) Feb 7 2008 42
Blossom Thinning i Resul ts look promising i Effect of various blossom thinne ers on number of fruit per tree of f'h 'Harrow Diamond d' peaches, 2004 800 600 400 200 0 Number of fruit per tree Untreated Control Hand Thinned Control 2% Mineral Oil + 2.5 5% LS 1.0% TMN-6 1% Citric ic Acid 1% ATS 0.75% TMN-6 2% Mine eral Oil 0.2% Regulaid 2% Citric ic Acid 0.50% TMN-6 2% ATS 4% Citric ic Acid 2% Entry 3% Entry Feb 7 2008 43
Summary of Peach Blos ssom Thinning Research Entry y and TMN-6 havethemost effective thinner: Reduced thinned fruit number Reduced final fruit set Increased fruit size Improved fruit quality Feb 7 2008 44
Flower Inhibitors GA 3 - stone fruit GA 4+7 - pome fruit Concept: reduce or prevent flower initiation, thereby minimizing the requirement for chemical and hand thinning Feb 7 2008 45
Feb 7 2008 46
Effect of GA Rate on Thinned Fruit Weight and Number d fruit weig ght, kg Thinne Fig. 5 Effect of GA concentration on thinned fruit weight and number per tree of "Red Haven" peach trees, 2003 12 10 8 6 4 2 0 Weight of hand thinned control Thinned fruit weight/ tree (kg) Thinned fruit number 0 50 100 200 400 Thinned fruit number/ tree 400 350 300 250 200 150 100 50 ber Thinned fruit num 0 Rate, mg/l GA significantly reduced the amount of hand thinning requirements (30% reduction for GA at 50 ppm) Feb 7 2008 47
Untreated control Feb 7 2008 48
GA at 100 ppm Feb 7 2008 49
Fig. 7 Effect of GA rate on crop load and fruit size of "Red Haven" peach trees, 2003 ield, kg Y 70 60 50 40 30 20 10 0 Yield Fruit size 200 150 100 50 0 Me ean fruit size, g 0 50 100 200 400 Rate, mg/l Total yield/ tree (kg) Mean fruit weigth (g) Significant GA rate and timing effect on crop load reduction; Increased fruit size Feb 7 2008 50
Summary - Gibberellic Acid Treatments Did not affect current season crop density, yield, or fruit size; Improved fruit quality; Reduced the need of hand thinning; Increased fruit size; Improved colour and SSC; Advanced maturity; Increased vegetative growth Feb 7 2008 51
Future of Plant Bioreg gulators in Tree Fruit Likely more specific on pla ant processes and environmentally safe compounds Growers need fruit thinners for stone fruit (blossom and/or fruitlet) t) Expansion in the use of GA as a flower inhibitor Abscisic acid and benefits for reducing water stress Need to clearly demonstrate the cost:benefit of PBRs Feb 7 2008 52
Unanswere d Questions Can cherries be chemically thinned (to improved fruit size)? Is there are PBR to re egulate the vegetative growth of peaches and cherries? Abscisic acid is the on nly plant hormone that has not been used commercially. Can ABA be used to reduced dr rought stress? Feb 7 2008 53