Subtropical Fruit Crops Research & Education
University of California
Subtropical Fruit Crops Research & Education

Posts Tagged: PGR

Charlie Coggins Was Citrus

Remembering UCR's Dr. Charlie Coggins
(Remembrance courtesy of the California Citrus Quality Council)

It is with deep sadness that we learned that Charles W. Coggins, Jr. passed away on Aug 18, 2019 at the age of 88.

Coggins was an industry pioneer who recognized the potential advances with plant growth regulators (PGRs), beginning with gibberellic acid (GA) and continuing with programs to retain 2,4-D.  It was said that his research on PGRs has been described as the single most economically beneficial research result of the last century.  He authored more than 100 technical publications and nearly 50 semi-technical publications that have proved to be invaluable tools for citrus growers worldwide.  He was the recipient of numerous awards for his leadership, agricultural excellence and research accomplishments.

Charlie, Professor Emeritus of Plant Physiology, officially retired from the University of California Riverside in 1994.  During his 37 years at the University, he served as Chairman of the UC Riverside Department of Plant Sciences and helped create the Department of Botany and Plant Sciences.  He also served 15 years as Executive Secretary/Treasurer for the International Society of Citriculture. To help succeeding generations of researchers, Coggins created The Coggins Endowed Scholarship Fund at UCR to provide financial assistance for graduate students in the College of Natural and Agricultural Sciences who demonstrate academic excellence, quality research and benefit to the citrus industry.

He served as Chairman of the Board of Directors for the CA Citrus Quality Council from Nov 1992 to Jan 2008. In 2003, he was presented with CCQC's highest honor, the Albert G. Salter Memorial award which recognizes and individual who has made outstanding contributions to and achievements in the citrus industry.
 
Charlie was born November 17, 1930 in North Carolina.  He was proceeded in death by two sons from cystic fibrosis.  He is survived by his wife Irene of 68 years, a son and four grandchildren. A memorial service is pending.  In lieu of flowers, contributions can be made to support his scholarship at UCR in honor of him, to the Parkinson's disease foundation or cystic fibrosis charities. Cards can be sent to 819 Alden Road, Redlands, CA 92373.

CLICK HERE FOR CITROGRAPH ARTICLE HIGHLIGHTING DR. COGGINS

The family of Dr. Charlie Coggins would like to welcome all
citrus industry friends to attend his memorial service. 


September 7, 2019 | 2:00 PM
First Baptist Church
51 West Olive Avenue
Redlands, California 92393

 

charlie coggins
charlie coggins

Posted on Thursday, August 22, 2019 at 3:29 PM
Tags: citrus (339), coggins (1), PGR (5)

Make More Avocado Fruit

Use of ProgGibb LV Plus® Plant Growth Regulator Increases Total Yield/                            Fruit Size of Hass  Avocados

As of March 27, 2018, foliar application of GA3 (ProGibb LV Plus®, Valent BioSciences, Corp.) to ‘Hass' avocado trees in commercial orchards has been approved. Dr. Carol J. Lovatt, emerita professor of plant physiology at the University of California – Riverside, recently completed research concerning the effectiveness of ProGibb LV Plus® on avocado fruit size and yield. A summary of her research — including best practices — follows.

Application Best Practices

ProGibb LV Plus® should be applied as a foliar spray when 50 percent of the trees in a block are at the cauliflower stage of inflorescence. If a grower cannot make an application at this time, it is best to apply the spray later, rather than earlier in order to ensure effectiveness.

The spray should be applied like a pesticide spray — full canopy coverage with a focus on the inflorescences. Those applying the spray should avoid spraying to run-off.

The ideal dilution for ground application is 12.5 fluid ounces of ProGibb LV Plus® (25 grams active ingredient [gai]) per 100 gallons of water/acre. For aerial application, use 12.5 fluid ounces (25 gai) in 75 gallons of water/acre. According to the research, the ideal application rate is 25g GA3 per acre; higher and lower doses were less effective. The pH of the water used should be adjusted such that the final pH of the spray solution is between pH 5.5 – 6.0.

Dr. Lovatt utilized organosilicone surfactant Silwett L-77® or Widespread Max® at a concentration of 0.05 percent as a wetting agent. Similar pure organosilicone type surfactants would be acceptable as wetting agents. It is important to note that until additional research can be conducted, other materials should not be included in the ProGibb LV Plus® spray solution.

Effect of ProGibb LV Plus® (GA3)

Dr. Lovatt's research team tested the effect of ProGibb LV Plus® on fruit size and yield for both ground and aerial applications. Overall, the research team noted that GA3 had no negative effects on ‘Hass' avocado fruit quality.

Ground applications were tested in March at groves located in Corona, Irvine and Somis, California. The tests were run on Duke 7 clonal rootstock trees at the cauliflower stage of inflorescence development. Each of the groves reported net increases in total yield and large/commercially valuable size fruit. The results were as follows:

Table 1. Effect of GA3 (25 g ai/acre) applied at the cauliflower stage of inflorescence development on yield and fruit size (pounds/tree) of ‘Hass' avocado trees in Corona, CA.

TreatmentTotal FruitNet Increase (%)Large fruit (213-354 g/fruit)Net increase (%)
 lb fruit/tree
GA3           74.7 az             84           34.3 a              128
Control            40.6 b             15.0 b  
P-value 0.0997   0.0657  

z Values in a vertical column followed by different letters are significantly different at specified P-values by Duncan's Multiple Range Test at the P-values indicated. (From the work of Salazar-García and Lovatt, 2000).

Table 2. Effect of GA3 (25 g ai/acre) applied at the cauliflower stage of inflorescence development on yield and fruit size as pounds and number of fruit per tree in an alternate bearing ‘Hass' avocado orchard in Irvine, CA.

 Year 1 Yield
TreatmentTotal FruitNet Increase (%)Valuable Size Fruit (178-325 g/fruit)Net increase (%)
GA3          92.2 az              70          67.9 a            65
Control          54.2 b            41.2 b  
P-value 0.0029   0.0037  
 
GA3         215 a             76          141 a            70
Control          122 b              83 b  
P-value 0.0042   0.0026  

z Values in a vertical column followed by different letters are significantly different at specified P-values by Duncan's Multiple Range Test at the P-values indicated. (From the work of Lovatt and Salazar-García, 2007; Zheng et al., 2011)

Table 3. Effect of GA3 (25 g ai/acre) applied at the cauliflower stage of inflorescence development at on yield and fruit size of ‘Hass' avocado trees in Somis, CA. Percent net increase reflects the benefit of GA3 at 25 g ai/acre relative to the untreated control trees.

TreatmentTotal FruitNet Increase (%)Valuable size fruit (178-325 g/fruit)Net increase (%)Large fruit (213-354 g/fruit)Net increase (%)
 lb fruit/tree
GA3       408.1 az         10      379.4 a            13       294.1 a           16
Control       372.6 b        335.3 b         253.3 b  
P-value 0.0626   0.0252   0.0626  

z Values in a vertical column followed by different letters are significantly different by Fisher's Protected LSD test at the P-values indicated.

Overall, ground application of GA3 resulted in a net increase of 3,905 lb/acre, with a net increase of 4,851 lb/acre of commercially valuable size fruit (packing carton sizes 60+48+40; 178-325 g/fruit) and a net increase in large fruit (packing carton sizes 48+40+36; 213-354 g/fruit) of 4,488 lb/acre.

Aerial applications were tested on groves located in Pauma Valley and Carpinteria, California. Together, the aerial applications demonstrated that GA3 increased fruit set (fruit retention) by 55 percent into the last week of August and fruit size by 6 percent through mid-August.

Ultimately, Dr. Lovatt's research indicates that use of GA3 could result in substantial increases in net dollar return per acre to the grower due to increase in yield and commercially valuable size fruit. In addition, growers whose avocado groves are not suited to ground applications (groves located on slopes or in high-density formations) can benefit from the efficacy of utilizing aerial applications. In summary, ProGibb LV Plus® is “vital to the California avocado industry to increase grower income per acre to help sustain the California avocado industry.”

N.B.  Remember, only well managed trees are going to respond.  This will not turn around a poor producing orchard. only potentially increase production on an already good producing orchard.  Ben

avocado fruit
avocado fruit

Posted on Thursday, April 19, 2018 at 7:23 AM
Tags: avocado (289), gibb (3), gibberelic acid (1), gibberellin (2), growth promoter (1), organic (12), PGR (5)

Improving Avocado Fruit Set

The California Avocado Commission is pleased to announce the availability of ProGibb LV Plus Plant Growth Regulator Solution (gibberellic acid) for use on avocados in California under a Special Local Needs (SLN) registration effective March 27, 2018. ProGibb has been shown to effectively increase fruit size and set when applied at the cauliflower stage of bloom.

ProGibb LV Plus can be applied from the ground or by air. Ground applications should be made by mixing 12.5 fluid ounces of product in 100 gallons of water per acre. Aerial applications should be made by mixing 12.5 fluid ounces of product in 75 gallons of water per acre. Only one (1) application is allowed per year.

The restricted entry interval (REI) is 4 hours, and the preharvest interval (PHI) is 0 days, so ProGibb LV Plus can be used with minimal disruption to harvesting and other grove management activities.

Please note:

  • A copy of the SLN Label must be in the possession of the user at the time of application.
  • The signature of the County Agricultural Commissioner or their designee must be obtained prior to the use of ProGibb LV Plus.
  • This SLN is only valid for the ProGibb LV Plus product manufactured by Valent BioSciences Corporation. Generic gibberellic acid products may not be used under this SLN.

The California Avocado Commission wishes to thank Dr. Carol Lovatt, University of California Riverside, for her many years of dedicated research that made this registration possible. We also thank the many growers, PCAs, and pesticide applicators who participated in the research trials.

If you have any questions about this SLN registration and the use of ProGibb LV Plus, please consult with your local PCA or you may contact Tim Spann at tspann@avocado.org.

Photo: Cauliflower stage of flowerr

avocado flower
avocado flower

Posted on Monday, April 2, 2018 at 5:39 AM
Tags: avocado (289), cauliflower (1), flower (1), frut set (1), gib (1), hormone (1), PGR (5)

It's That Season Again When Growers Are Being Asked to Buy Products

Growers are faced with an ever-changing list of commercial “tools”, each with the promise of providing some advantage to the farmer.  Frequently, these are new fertilizer mixes presented as proprietary cocktails promoted and dispensed with promises of a multitude of profitable (yet improbable) benefits to the buyer. With the large number of new products available, and the number of salespeople promoting them, it is often difficult for growers to distinguish between products likely to provide real benefit, and those that may actually reduce the profitability of the farm.   
 
In all situations when a company approaches the University or a commodity research board with a new product or technology for sale to California growers, these institutions act as grower advocates.  They are charged with sorting through the available information; asking the right questions; getting the necessary research done if the available information warrants this pursuit; disseminating accurate information on these new technologies and products, and doing all that can help maximize grower profits now and in the future.  When approached with a new product or technology it is obligatory to challenge claims with the following questions:
 
Is there some basic established and accepted scientific foundation on which the product claims are made?

Language that invokes some proprietary ingredients or mysterious formulations, particularly in fertilizers mixes registered in the State of California, raises red flags. A wide range of completely unrelated product benefit claims (such as water savings, pesticide savings, increased earlier yield) raises more red flags.  Product claims that fall well outside of any accepted scientific convention generally mean the product is truly a miracle, or these claims are borderline false to entirely fraudulent.  Some of the water treatment products on the market fall into this category and can easily be checked against some of the studies found at this site:  http://www.chem1.com/CQ/index.html


 
Has the product undergone thorough scientific testing in orchards?
 
Frequently, products are promoted based on testimonials of other growers. While testimonials may be given in good faith, they are most often not backed up by any real scientific testing where a good control was used to compare orchard returns with and without the product.
 
A “test” where a whole block was treated with a product and which has no reliable untreated control does not meet accepted standards for conducting agricultural experiments. Also, a treated orchard cannot reliably be compared to a neighboring untreated orchard; and a treated orchard cannot be compared to the same orchard that was untreated the previous crop year.  Even a test with half a block of treated trees and half untreated is not considered dependable by any known scientific standard of testing.
 
Only a well designed, statistically replicated, multi-year trial allows for direct comparison of untreated versus treated trees with statistical confidence. Verifiable data from tests that meet acceptable standards of scientific design, along with access to raw baseline (before treatment) yield data from the same trees (preferably for the two years prior) should be used to determine the validity of test results provided.
 
Are the test results from a reliable source?
 
If the testing were not done by a neutral party, such as university scientists, agency, or a reputable contract research company using standard scientific protocols, this raises red flags.  If the persons overseeing the tests have a financial interest in seeing positive results from the product, it raises red flags.
  
Does the product have beneficial effects on several unrelated farm practices?
 
A product that increases production of trees, makes fruit bigger, reduces pests, reduces water use, and reduces fertilizer costs, is more than a little suspicious. In reality, if such a product really existed, it would not need any testing at all because its benefits would be so obviously realized by the grower community that it would spread rapidly by word of mouth and embraced by the entire grower community.
 
Are other standard and proven farm products put down in the new product sales delivery?
 
If a new product vendor claims that their product is taken up 15 times faster than the one growers are currently using, or is 30 times more efficient, it probably costs 15 to 30 times more per unit of active ingredient than the standard market price.  Growers should always examine the chemical product label to see what active ingredient they are buying.  There has to be a very good reason to pay more for an ingredient where previously there had been no problem supplying the same ingredient at a cheaper price to trees in the past.

So what is a grower to do ?

New products come and go.  Snake oil products often disappear rapidly, when their efficacy fails to materialize after application.  Products that confound their purported results with fertilizers or growth stimulators can persist, but eventually they too fail to live up to expectations at some point and will fade from popularity.  Try to obtain some kind of consensus with university‚Äźbased research or other peer reviewed research reports, field efficacy trials that you run for yourself, and not on the testimonials of others.   If you decide to conduct your own trials, they must be replicated and statistically analyzable, otherwise they are little more than anecdotal observations that have little value in quantifying the effects of a product or practice.  For more help with trials, seek out University Extension advisors and specialists.  This is their job, and they are willing partners in field research.   After awhile, you will be able to ascertain the nature of the “oil” before you purchase it.

unknown product
unknown product

Posted on Friday, March 9, 2018 at 5:55 AM

PGRs aand Olives

Advances in mitigation of alternate bearing of olive: vegetative growth response to plant growth regulators

Elizabeth Fichtner, UCCE Farm Advisor, Tulare County, and Carol Lovatt, Professor of Plant Physiology, Botany and Plant Sciences, UC-Riverside.

Alternate bearing (AB) is a phenomenon in olive where fruit production alternates between large crops consisting of smaller, lower value fruit during an ‘"ON’ year and smaller crops consisting of larger, higher value fruit during an "OFF" year. The large swings in biennial olive production impact the overall industry, from growers to harvesters, to processors. In olive, the vegetative growth in one year produces the nodes bearing potential floral buds in the spring of the second year. Fruit suppress vegetative shoot growth resulting in fewer nodes available to bear fruit the following year. Our phenological studies have helped characterize the relationship between fruit load and vegetative growth on ‘Manzanillo’ olives in Tulare County, California.

Investigation of vegetative growth response to plant growth regulators

One strategy proposed to mitigate AB is to stimulate summer vegetative shoot growth to increase the number of nodes with the potential to produce floral buds. To address this strategy, our research team designed and implemented a proof-of-concept study in which plant growth regulator (PGR) treatments were injected into individual scaffold branches on opposing sides of ’ON‘ and ’OFF‘ trees. Plant growth regulators utilized in the study included two cytokinins, 6-benzyladenine (6BA) and a proprietary cytokinin (PCK), as well as two auxin-transport inhibitors, tri-iodobenzoic acid (TIBA) and a natural auxin transport inhibitor (NATI). Eight PGR treatments were included, with each PGR tested alone, and each cytokinin tested in combination with each auxin-transport inhibitor. PGR treatments were implemented in Summer (July 2012), and Summer + Spring (July 2012 and February 2013). Vegetative shoot growth was recorded monthly throughout the year to determine the influence of PGR treatments and timings on node production. The study was completed at the Lindcove Research and Extension Center (Exeter, CA).

Node production in response to plant growth regulator treatments

Scaffold injection with numerous PGR treatments resulted in significant increase in vegetative shoot growth. For example, nonbearing shoots on ‘ON’ control trees, produced an average of one node between July 2012 and February 2013, whereas nonbearing shoots on   PGR-treated scaffold branches exhibited almost 4 times the new growth of the control trees (Table 1, shaded). Importantly, the new growth in some cases was statistically equal to and numerically greater than the new vegetative shoot growth of nonbearing shoots on ‘OFF’ control trees. The PGR treatments also had a positive effect in increasing vegetative shoot growth on bearing shoots of ‘ON’ crop trees. Bearing shoots on ‘ON’ control trees produced an average of 0.8 nodes between July 2012 and February 2013, whereas bearing shoots on PGR-treated scaffold branches of ‘ON’ trees produced over three-fold more nodes during this period. Some PGR treatments increased the number of new nodes on bearing shoots on ‘ON” trees to values equal to those of nonbearing shoots of ‘OFF’ crop control trees (Table 1, asterisk). Identify the better treatments. On average two additional nodes of growth were added to shoots in all treatments from February through April. Thus, in April shoots treated with some PGRS (Table 1, shaded) remained longer than bearing or nonbearing shoots on ‘ON’ crop control trees and equal to nonbearing shoots on ‘OFF’ crop control trees. This result suggests that with regard to increasing vegetative shoot growth there was no advantage derived from supplementing the Summer PGR treatment with the second Spring PGR treatment. However, the effect of the Spring PGR treatments on floral bud break and return bloom and fruit set remains to be determined.

Table 1. The effect of scaffold branch injected plant growth regulator treatments on vegetative shoot growth, as number of new nodes produced.

 

 

New Nodes

Treatment

Branch Status

July-February

July-April

ON Control

Fruit

0.8 l

3.3 jkl

TIBA+6BA SUMMER

Fruit

2.3 hijk*

4.6 cdefghij

TIBA+PCK SUMMER

Fruit

2.5 ghij*

4.9 bcdefghij

NATI+6BA SUMMER

Fruit

2.7 fghij*

4.2 fghijkl

NATI+PCK SUMMER

Fruit

2.2 hijk*

3.9 hijkl

TIBA SUMMER

Fruit

2.4 hij*

4.9 bcdefghij

NATI SUMMER

Fruit

2.5 fghij*

4.3 efghijkl

6BA SUMMER

Fruit

2.2 ijkl

4.2 fghijkl

PCK SUMMER

Fruit

2.6 fghij*

4.7 cdefghij

TIBA+6BA SUMMER+SPRING

Fruit

2.4 hij*

4.5 defghijk

TIBA+PCK SUMMER+SPRING

Fruit

3.0 efghi*

4.5 defghij

NATI+6BA SUMMER+SPRING

Fruit

2.6 fghij*

5.0 abcdefghij

NATI+PCK SUMMER+SPRING

Fruit

2.2 ijk*

3.7 ijkl

TIBA SUMMER+SPRING

Fruit

2.0 ijkl

4.1 ghijkl

NATI SUMMER+SPRING

Fruit

3.1 defghi*

5.5 abcdefghi

6BA SUMMER+SPRING

Fruit

2.7 fghi*

4.9 bcdefghij

PCK SUMMER+SPRING

Fruit

1.3 jkl

2.5 l

OFF Control

No Fruit

3.6 abcdefgh

5.0 bcdefghij

ON Control

No Fruit

1.0 kl

2.7 kl

TIBA+6BA SUMMER

No Fruit

3.8 abcdefg

4.7 cdefghij

TIBA+PCK SUMMER

No Fruit

4.7 ab

5.9 abcdefg

NATI+6BA SUMMER

No Fruit

4.8 a

6.3 abcd

NATI+PCK SUMMER

No Fruit

4.5 abc

6.0 abcde

TIBA SUMMER

No Fruit

4.4 abcd

6.0 abcdef

NATI SUMMER

No Fruit

4.2 abcde

4.9 bcdefghij

6BA SUMMER

No Fruit

3.4 bcdefghi

4.0 hijkl

PCK SUMMER

No Fruit

4.3 abcde

5.5 abcdefghi

TIBA+6BA SUMMER+SPRING

No Fruit

4.2 abcde

5.2 abcdefghi

TIBA+PCK SUMMER+SPRING

No Fruit

4.8 a

5.7 abcdefgh

NATI+6BA SUMMER+SPRING

No Fruit

3.9 abcdef

5.1 abcdefghi

NATI+PCK SUMMER+SPRING

No Fruit

3.2 cdefghi

4.2 efghijkl

TIBA SUMMER+SPRING

No Fruit

4.8 a

6.5 ab

NATI SUMMER+SPRING

No Fruit

4.5 abc

6.8 a*

6BA SUMMER+SPRING

No Fruit

4.8 a

6.4 abc

PCK SUMMER+SPRING

No Fruit

3.6 abcdefgh

4.7 cdefghij

P-value

 

<0.0001

<0.0003

Note: shading denotes treatments significantly different than ON Control + Fruit treatment. Asterisk denotes treatments significantly different than OFF Control (- Fruit).

 

Summary

These preliminary data demonstrate that PGRs increase shoot growth, which might result in more nodes with the potential to produce inflorescences the following spring. Future studies are anticipated to address the use of promising treatments in foliar applications. Naturally-occurring compounds, such as PCK and NATI, may be easier and less costly to register than PGRs, which are classified as pesticides. Therefore, significant growth response to the natural compounds tested may have commercial benefit even if proven less efficacious than the synthetic PGRs.

Acknowledgements: The financial support of the California Olive Committee and the technical support of the Lindcove Research and Extension Center were integral to the success of this project.

 

 

 

 

 

 

 

olive tree
olive tree

Posted on Monday, November 25, 2013 at 7:06 AM
  • Author: Elizabeth Fichnter and Carol Lovatt
Tags: 6-benzyladenine (1), alternate bearing (5), auxin (1), cytokinin (1), NATI (1), off (1), olive (10), on (1), PGR (5), TIBA (1), tri-iodobenzoic acid (1)
 
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