scholarly journals Characterizing the Interaction between NAA and BA on Apple Fruit Abscission and Development

HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1794-1801 ◽  
Author(s):  
Martin J. Bukovac ◽  
Paolo Sabbatini ◽  
Philip G. Schwallier ◽  
Michael Schroeder
Keyword(s):  
Strong Interaction ◽  
Fruit Size ◽  
Apple Fruit ◽  
Fruit Growth ◽  
Crop Load ◽  
Fruit Thinning ◽  
Small Fruit ◽  
Golden Delicious ◽  
Fruit Formation ◽  
Fruit Diameter

NAA and BA are important compounds for regulating crop load in apples (Malus domestica Borkh.). When used for fruit thinning, both induce abscission, but at an equivalent crop load NAA tends to reduce and BA to increase fruit size. There is a strong interaction between NAA and BA when used together on ‘Delicious’ and ‘Fuji’, leading to excessive development of pygmy and small fruit (<65 mm diameter). The combination of BA (as Promalin, 1:1 BA + GA4+7) applied at king bloom (KB) and NAAm (amide) at petal fall increased the percentage of small fruit by 3.3- or 5.1-fold compared with BA or NAAm alone. Similar results were obtained with BA (Promalin) at KB oversprayed with NAA at 10 to 12 mm king fruit diameter (KFD). When NAA was oversprayed with BA during fruitlet development, i.e., 5 to 6 mm, 10 to 12 mm, and ≈18 mm KFD, the greatest inhibition of fruit growth occurred at the 10- to 12-mm KFD stage, and there was no significant effect at 18 mm KFD. Inhibition by treatment at the 5- to 6-mm stage was intermediate and trees were overthinned. NAA + BA inhibition of fruit growth in ‘Delicious’ and ‘Fuji’ was not crop load-dependent. In all experiments, crop load (wt basis) of trees treated with NAA + BA was similar or less than of those treated with NAA or BA alone, but they produced 2.5- to 5-fold more small fruit. NAA + BA increased the number of fruit per cluster, many of which failed to fully develop. Increasing the ratio of BA to NAA from 25:15 to 125:15 mg·L−1 increased small fruit formation. The presence of GA4+7 in commercial formulations of BA (0:100, Maxcel; 10:100, Accel; 50:50, Promalin) did not significantly affect the NAA + BA response. Fruit growth was not inhibited by the NAA + BA combination in large-fruited ‘Golden Delicious’ and ‘Jonagold’ and was increased in small-fruited ‘Elstar’ and ‘Gala’ compared with the nontreated control.

scholarly journals Growth Response of Apple Fruit to NAA and Accel: Effect of Intraspur Competition and Position on a Spur

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 765D-765
Author(s):  
Brent L. Black ◽  
Martin J. Bukovac ◽  
Matej Stopar
Keyword(s):  
Growth Response ◽  
Fruit Size ◽  
Apple Fruit ◽  
Fruit Growth ◽  
Crop Load ◽  
Commercial Thinning ◽  
Whole Tree ◽  
Fruit Diameter

Apple fruit size is influenced by position on the spur, and location and number of competing fruits. King fruit appear to have the greatest potential to size and grow best in the absence of intraspur fruit competition (ISFC). Accel (A) and NAA (N), commercial thinning chemicals, influence fruit size beyond their effects on crop load. A 2-year study was conducted to determine the effect of ISFC and position (king, K, or lateral, L) on fruit growth in response to A and N. Branches from `Redchief Delicious' were thinned, after petal fall, to one K, one L, one K + one L, or two L fruits per spur. Whole-tree treatments of N (15 mg·liter–1), A (50 mg·liter–1, 1993; 25 mg·liter–1), and a combination (N+A) were applied at 10-mm king fruit diameter. A nontreated control was included. In 1993, N and N+A reduced fruit size only with ISFC, while A increased fruit size in the absence of ISFC. In 1994, A had no effect, but N and N+A reduced fruit growth with ISFC. In both seasons, A and N decreased the frequency of spurs bearing multiple fruit, while N+A dramatically increased number of spurs with multiple fruits (branch survey).

scholarly journals Interaction of NAA with Accel and Promalin on Fruit Size in `Delicious' and `Empire' Apples

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 765C-765
Author(s):  
Martin J. Bukovac ◽  
Brent L. Black ◽  
Jerome Hull
Keyword(s):  
Strong Interaction ◽  
Fruit Size ◽  
Split Application ◽  
Fruit Thinning ◽  
Small Fruit ◽  
Fruit Diameter

NAA and Accel are used for fruit thinning of apples. However, when combined, many small (<65 mm) fruit were produced in `Delicious'. We extended our studies using Redchief `Delicious' and `Empire', and, since BA is common to both Accel and Promalin, to study the effect of NAA-thinning sprays on Promalin-treated Redchief trees. NAA (10–15 mg·liter–1) and Accel (25–100 mg·liter–1) were applied to Redchief and `Empire' at 100-mm king fruit diameter (KFD). NAA interaction with Promalin was studied using Redchief. Promalin (1.5 pt/A) was applied as a single spray (80% king bloom, KB) and as a split application (0.75 pt/A, 80% KB and repeated at 10-mm KFD) with NAA (15 mg·liter–1) at 10-mm KFD. In `Delicious', 2% to 9% of the fruit from Accel-treated trees was <65 mm in diameter, compared to 11% for NAA alone. However, when NAA was applied with Accel, 22% to 30% of the fruit was <65 mm and percentage of large fruit (75 mm+) was reduced by 24% to 36%. There was no strong interaction for fruit size in `Empire', but the combination decreased yield. NAA applied to Promalin-treated `Delicious' increased percentage of small fruit dramatically (14% to 25%). No increase in small fruit was observed with Accel of Sevin.

Interaction Between CPPU and NAA on Fruit Thinning and Fruit Development in Selected Apple Cultivars

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 513c-513 ◽  
Author(s):  
Martin J. Bukovac ◽  
Jerome Hull ◽  
John C. Neilsen ◽  
Michael Schroeder ◽  
Georg Noga
Keyword(s):  
Total Yield ◽  
Fruit Size ◽  
Frost Damage ◽  
Fruit Growth ◽  
Soluble Solids ◽  
Seed Number ◽  
Crop Load ◽  
Fruit Thinning ◽  
Carpel Development ◽  
Return Bloom

NAA is used extensively for fruit thinning of apples to increase fruit size and to promote return bloom. In some cultivars, even if thinning is achieved, fruit size at harvest may be less than expected based on crop load. CPPU, N-(2-chloro-4-pyridinyl)-N.-phenylurea, has been shown to increase fruit growth in apples, grapes, and kiwi. We evaluated combinations of NAA and CPPU on thinning, fruit growth and return bloom in Redchief `Delicious', `Elstar', and `Gloster'. CPPU was applied at 5 mgμL–1 (based on 0 to 10 mgμL–1 response curve) in combination with 15 mgμL–1 NAA as high-volume sprays at 7 to 10 mm KFD. Yield and fruit size distribution (on total yield) were used as index of response. In `Delicious', CPPU (3-year study) increased % large (70 mm+) fruit, but in the presence of NAA % large fruit was reduced 2 of the 3 years. CPPU did not induce significant thinning. There were no significant effects on color or soluble solids; firmness was increased slightly and seed number reduced. The L/D ratio was increased and uneven lobe and carpel development was common. CPPU had no significant effect on return bloom in presence or absence of NAA, but NAA increased bloom in both the presence and absence of CPPU. With `Elstar' (2-year study) there was no significant thinning with either chemical, but CPPU increased mean fruit size and % large (70–80 mm) fruit over nonthinned, but not significantly greater than NAA alone. There were no significant differences in firmness, color, soluble solids or seed number. NAA + CPPU did not inhibit fruit growth or cause excessive uneven carpel development. Frost damage reduced crop load in `Gloster' where results were similar to `Elstar' except seed number was reduced by the NAA + CPPU combination.

scholarly journals Temperature Has a Greater Effect on Fruit Growth than Defoliation or Fruit Thinning in Strawberries in the Subtropics

Agriculture ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 127
Author(s):  
Christopher M. Menzel
Keyword(s):  
Opposite Effect ◽  
Fruit Size ◽  
Fruit Weight ◽  
Fruit Growth ◽  
Effect Of Temperature ◽  
Fragaria Ananassa ◽  
Fruit Thinning ◽  
Mature Leaves ◽  
Small Fruit ◽  
Marketable Fruit

Fruit size declines in strawberries (Fragaria × ananassa Duch.) as the season progresses in many subtropical areas, possibly due to inadequate leaf area, over-cropping, or high temperatures. An experiment was conducted to investigate the importance of these factors on fruit growth in ‘Festival’ in Queensland, Australia. Groups of plants were defoliated to remove half of the mature leaves on each plant, thinned to remove all the inflorescences on each plant, or defoliated and thinned. Control plants were left intact. Defoliation, thinning, or defoliation + thinning decreased yield (total and/or marketable) by 15% to 24% compared with the control. Defoliation, or defoliation + thinning decreased average fruit weight (total and/or marketable fruit) by 1 to 2 g compared with the control, whereas thinning had the opposite effect. The incidence of small fruit increased towards the end of the season. There were strong relationships between fruit weight and average daily mean temperature in the seven weeks before harvest (R2s greater than 0.80). Fruit weight decreased from 24 g to 8 g as the temperature increased from 16 °C to 20 °C. This response was not affected by defoliation or thinning. The strong effect of temperature on fruit size indicates a problem for production in the future in the absence of heat-tolerant cultivars.

scholarly journals APPLE FRUIT CHEMICAL THINNING IN CHIHUAHUA, MÉXICO

2008 ◽  
Vol 31 (3) ◽  
pp. 243
Author(s):  
David I. Berlanga-Reyes ◽  
Alejandro Romo-Chacón ◽  
Ángel R. Martínez-Campos ◽  
Víctor M. Guerrero-Prieto
Keyword(s):  
Fish Oil ◽  
Fruit Set ◽  
Fruit Size ◽  
Apple Fruit ◽  
Naphthalene Acetic Acid ◽  
Alternate Bearing ◽  
Fruit Thinning ◽  
Equatorial Diameter ◽  
Large Trees ◽  
Golden Delicious

Chemical fruit thinning is a common practice in apple (Malus x domestica Borkh.) orchards for achieving high quality fruits, reduced costs of hand-thinning and promote return of flowering. Hand thinning is a common and high cost practice, not only due to the labor involved, but also because seedling and vigorous clonal rootstocks result in large trees. The chemical thinning agents: Ethephon (ETH), Carbaryl (CB), Naphthalene acetic acid (NAA), 6- Benzyladenine (6-BA), and fish oil were evaluated on ‘Golden Delicious’ and ‘RedChief Delicious’ apple trees in 2004 and 2005. Chemical thinning effect was compared with early and late handthinnings. Treatments were sprayed when the biggest fruit in the clusters was 10 mm in equatorial diameter. NAA showed the best effect in reducing final fruit set in both cultivars and years evaluated, with results comparable to those of early hand-thinning (thinned when king-fruit size was 10 mm) in ‘Golden Delicious’ trees. In ‘RedChief Delicious’, fruit set reduction by NAA, fish oil and CB treatments was similar to early hand-thinned trees only in 2005. In 2005, time spent during supplementary hand-thinning in ‘Golden Delicious’ trees was reduced by chemical thinning treatments, except by fish oil; whereas in ‘RedChief Delicious’ only NAA K-salt reduced it in 2004. An increase in fruit equatorial diameter was observed only in 2004 with NAA and fish oil. Alternate bearing, typical of ‘Golden Delicious’, was not diminished by these chemical thinning treatments.

scholarly journals Cropping and Fruit Growth in Redchief `Delicious': An Analysis of the Effect of NAA and Cytokinins

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 525A-525
Author(s):  
Martin J. Bukovac ◽  
John C. Neilsen ◽  
Jerome Hull
Keyword(s):  
Fruit Size ◽  
High Volume ◽  
Inhibitory Effect ◽  
Tree Age ◽  
Marked Variation ◽  
Crop Load ◽  
Fruit Thinning ◽  
Single Tree ◽  
Small Fruit ◽  
Effect On Yield

Generally, NAA is effective in inducing fruit thinning in `Delicious'. Although significant thinning may be induced, fruit size at harvest may not be closely related to crop load. Further, the magnitude of response to NAA may vary markedly between seasons. Herein, we present an analysis of response of `Redchief Delicious' over several years (tree age 11–14 years old) to high-volume sprays of NAA (15 mg·L–1), BA (25-50 mg·L–1), and CPPU (5 mg·L–1) at KFD of 8–12 mm. A single tree was used for each treatment replicated four to six times and response was measured by yield and fruit size distribution for each tree. In eight experiments over 4 years, NAA resulted in an average 22% reduction in yield, a 5.1% reduction in large fruit (70 mm+) and 2% reduction in small (<64 mm) fruit compared to NTC. There was a marked variation in response among years. Over 4 years, BA averaged a 5% decrease in yield, a 15% increase in large fruit and a 21% decrease in small fruit. In contrast, when NAA was combined with BA at 25-50 mg·L–1, yield decreased an average of 30%, large fruit decreased by 68%, and small fruit increased 8-fold (2.54 vs 20.6 kg/tree). CPPU alone (2-year study) had no significant effect on yield, but increased large fruit by 60% and significantly reduced production of small fruit. When CPPU was combined with NAA, yield was reduced in both years and the amount of large fruit was increased in 1995, but decreased in 1996. NAA had a very inhibitory effect on fruit size in 1996. One explanation may be that the crop was produced by lateral fruit (king flowers were lost to frost), and NAA has a greater inhibitory effect on lateral than king fruit. Results will be discussed in relation to studies with `Jonathan' and `Empire'.

scholarly journals 166 Influence of Crop Level on Growth and Quality of `Braeburn' Apple Fruit

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 418E-419
Author(s):  
P.I. Garriz ◽  
G.M. Colavita ◽  
H.L. Alvarez
Keyword(s):  
Fruit Size ◽  
Growing Season ◽  
Apple Fruit ◽  
Full Bloom ◽  
Cross Sectional ◽  
Crop Load ◽  
Commercial Crop ◽  
Source Sink ◽  
Fruit Diameter

Crop load and the genetic biological carrying capacity (source–sink relationships) determine the potential for fruit size development on apple; however, the environment within which the fruit grows attenuates this potential. The effects of different crop loads on the growth pattern and the progress of maturity in apples were evaluated at the Comahue National Univ., Argentina (lat. 38 56'S long 67 59'W), during the 1998–99 growing season. Our experiment was conducted on 6-year-old `Braeburn'/Malling Merton 111 apple (Malus domestica Borkh.) trees spaced 4.0 × 2.3 m and trained to palmette leader. Treatments were 1) light crop load (LC), 2.5 fruit/cm2 trunk cross-sectional area (TCSA), 2) moderate crop load (MC), 6.5 fruit/cm2 TCSA (standard commercial crop load) and 3) high crop load (HC), minimum 8 fruit/cm2 TCSA, no fruit removed from tree. Whole trees were hand-thinned 19 days after full bloom (DAFB). Fruit diameter (FD) was taken at two weekly intervals (n = 24 per date and treatment) and maturity indexes were determined at harvest. Analysis of variance was used and mean separations were computed with Student's t test. From 38 DAFB until harvest, fruit size was significantly reduced (P < 0.01) in the HC trees, indicating that they were source-limited during growth. At 166 DAFB, FD was 7.48, 7.14, and 6.89 cm for the LC, MC and HC treatments, respectively. Adequate carbon was apparently available to support a commercial crop load since no differences were found between LC and MC trees. Crop level influenced flesh firmness; at 173 DAFB, it was significantly lower in HC trees than MC and LC trees (84.33, 92.51, and 91.57 N, respectively). These results suggest some goals of thinning for ensuring sizable `Braeburn' fruit.

scholarly journals Cultivar-specific Apple Fruit Growth Rates in Vivo and Sink Activities in Vitro

1992 ◽  
Vol 117 (3) ◽  
pp. 459-462 ◽  
Author(s):  
Douglas D. Archbold
Keyword(s):  
Growth Rates ◽  
Fruit Size ◽  
Apple Fruit ◽  
Fruit Growth ◽  
Sink Strength ◽  
Golden Delicious ◽  
Days To Maturity ◽  
Physiological Constraint

Absolute and relative fruit growth rates (AGR and RGR) of apple (Malus domestics Borkh.) were calculated from the fruit dry weights of several cultivars harvested periodically following June drop during 1988-90. AGRs were constant or varied slightly, and RGRs generally declined as the season progressed. Generally, both AGR and RGR values were higher for relatively large fruit of several cultivars with similar days to maturity, e.g., `McIntosh' vs. `Jonathan' and for summervs. fall-ripening cultivars, e.g., `Stayman' vs. others. An exception was observed in 1990, when `Golden Delicious' exhibited a higher AGR but lower RGR than `Rome Beauty', yet ripened 1 month earlier. `Golden Delicious' AGR and RGR values were lower for both fruit of a pair on a spur than the values for a single fruit on a spur, and the dominant fruit of the pair exhibited higher growth rates than the inferior fruit. Rates of sorbitol accumulation (SAR) by cortex disks incubated in 14C-labeled sorbitol solutions in vitro declined as the season progressed. Within a cultivar, SARS were not related to fruit size, nor were differences found between cortex disks from competing fruit on a spur, although SARS were higher for both competing fruit on a spur as compared to that of a single fruit per spur. Due to a positive correlation between RGR and SAR values, the SAR of cortex cells may be regulated in such a manner as to be a physiological constraint on fruit sink strength and growth rate.

scholarly journals Effect of CPPU and NAA on Fruit Growth and Cropping of Redchief `Delicious'

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 597f-598
Author(s):  
Martin J. Bukovac ◽  
John C. Neilsen ◽  
Jerome Hull
Keyword(s):  
Fruit Size ◽  
High Volume ◽  
Significant Inhibition ◽  
Fruit Growth ◽  
Fruit Thinning ◽  
Single Tree ◽  
Highly Active ◽  
Seed Content ◽  
Old Trees ◽  
Fruit Diameter

NAA is commonly used for fruit thinning of apples. However, with spur-type `Delicious' fruit, size may be less than expected based on the remaining crop load. Attempts to enhance fruit size on NAA-thinned trees with benzyladenine (BA) resulted in an interaction causing an increase in small (≤64 mm) fruit. CPPU [N-(2-chloro-4-pyridinyl)-N'-phenylurea], a highly active cytokinin in promoting parthenocarpy and growth of a number of fruit, was evaluated alone and with NAA for its effects on cropping and fruit growth in Redchief `Delicious'. High-volume sprays of CPPU were applied at 0, 2.5, 5, and 10 mg·L–1 to 13-year-old trees at 7.26 mm king fruit diameter. NAA was applied at 15 mg·L–1 with and without CPPU at 5 mg·L–1. Each treatment consisted of a single tree replicated four times. Response was evaluated by determining yield per tree and fruit size distribution at harvest. CPPU increased the amount of large (≥70 mm) fruit produced without significantly reducing yield. The amount of large fruit produced was 35, 71, 91 and 85 kg/tree for the nonthinned control (NTC) and CPPU at 2.5, 5, and 10 mg·L–1, respectively. NAA (15 mg·L–1) reduced yield by 39 kg/tree and increased amount of large fruit by 44 kg/tree. When CPPU (5 mg·L–1) was oversprayed with NAA (15 mg·L–1), yield was reduced by 30 kg/tree, and amount of large fruit was increased by 56 kg/tree compared to the NTC. The interaction was not significant for yield but was significant (P = 0.01) for amount of large fruit produced. Seed content was significantly reduced by NAA and CPPU, the effect being greater for NAA and in small (51 to 56 and 57 to 63 mm) than in large (76 to 82 mm) fruit. These data showing no significant inhibition of fruit growth with a combination of NAA and CPPU in Redchief `Delicious' are in contrast with findings for a related cytokinin, BA, where fruit growth was depressed significantly when combined with NAA.

scholarly journals 297 EFFECTS OF NAA ON FRUIT SIZE OF `DELICIOUS' APPLES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 472f-472
Author(s):  
Brent L. Black ◽  
Martin J. Bukovac ◽  
Jerome Hull
Keyword(s):  
Growth Rate ◽  
Fruit Size ◽  
Spray Application ◽  
Time Of Application ◽  
Fruit Thinning ◽  
Growing Seasons ◽  
Small Fruit ◽  
Constant Dose ◽  
Carrier Volume ◽  
Fruit Diameter

Post-bloom fruit thinning of spur-type `Delicious' with NAA may occasionally result in excessive small fruit (50 - 67 mm) not correlated with crop load. We evaluated the effect of carrier volume and time of application on incidence of small fruit over three growing seasons. A constant dose of NAA (30 g·ha-1) was applied in 230 to 2100 liter·ha-1 at about 10 mm king fruit diameter (KFD). Amount of NAA-induced small fruit differed from year to year, but there was no significant effect of carrier volume in any given year. NAA (15 mg·liter-1) was applied as a dilute spray at 5 to 22 mm KFD. Time of application influenced fruit size distribution at harvest in only one of three years. The incidence of small fruit appeared more closely related to temperature during spray application than to carrier volume or time of application. The effect of NAA on growth rate of king fruit with minimal competition (branches hand thinned, no lateral fruit) was determined over the first month after thinning. There was no pronounced effect of NAA on post-treatment growth rate. In a related study, NAA caused a significant decrease in fruit size when two or more fruit were competing on the same spur, while fruit size in the absence of intra-spur competition was not significantly reduced.

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