Thinning of Spur `Delicious' Apples by Shade, Terbacil, Carbaryl, and Ethephon

Byers, Ross E.; Barden, J. A.; Carbaugh, D.H.

doi:10.21273/jashs.115.1.9

Cited by 49 publications

(25 citation statements)

References 8 publications

(6 reference statements)

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“…Through experiments involving defoliation treatments, these authors suggested that ethylene is the last hormonal effector of fruitlet abscission during this period. Actually, it is well known that exogenous ethylene or promoters induce fruit abscission in various fruit trees (Byers et al 1990a;Untiedt and Blanke 2001). Furthermore, reductions in the abscission rates during citrus fruit set have been obtained using ethylene biosynthesis inhibitors like 2-aminoethoxyvinyl glycine (AVG; see Ogata et al 2002).…”

Section: Discussionmentioning

confidence: 99%

Carbohydrate and ethylene levels related to fruitlet drop through abscission zone A in citrus

Iglesias

Tadeo

Primo‐Millo

et al. 2006

Trees

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Citrus fruits have two abscission zones (AZ), named A (in the pedicel) and C (in the calyx). Early fruitlet abscission takes place exclusively through AZ A, while at June drop it is progressively inactivated and AZ C begins to operate. In previous work, it has been demonstrated that carbohydrate and ethylene regulate fruit drop through abscission zone C. In this paper, we have analysed the effect of these two factors in developing fruitlets of Satsuma mandarins (Citrus unshiu [Mak.] Marc.) cv. Okitsu to elucidate their involvement on abscission through AZ A. The data indicated that ACC content and ethylene production of fruitlets paralleled abscission rates. Sucrose supplementation increased fruit set, although did not counteract the abscising effect induced by ACC. Branch girdling of terminal fruitlets carrying several leaves significatively reduced ethylene production and abscission rates, and increased sugar content. Pedicel girdling showed the opposite. Taken together, the results revealed that the carbohydrate content may be a biochemical signal involved in the mechanisms controlling abscission through AZ A. The evidence also showed parallelisms between ethylene and its activation. As the induction of higher ethylene levels after the period of AZ A activity, however, was not able to promote fruit drop, it is also concluded that solely ethylene is not sufficient to activate abscission.

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Section: Discussionmentioning

confidence: 99%

Carbohydrate and ethylene levels related to fruitlet drop through abscission zone A in citrus

Iglesias

Tadeo

Primo‐Millo

et al. 2006

Trees

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show abstract

“…Partial defoliation of citrus seedlings, however, can increase photosynthetic rates of remaining leaves in proportion to the number of vegetative buds that are allowed to regrow (Syvertsen, 1994). Canopy shading or application of photosynthetic inhibitors shortly after bloom reduced carbohydrate available to developing fruitlets and increased early fruit abscission of orange (Moss, 1976), litchi (Yuan and Huang, 1988), peach (Byers et al, 1985), and apple trees (Byers et al, 1985(Byers et al, , 1990Yuan and Greene, 2000a). In addition, fruit weight from girdled branches at harvest decreased with decreasing leaf area per fruit in various fruit crops (Fishler et al, 1983;Roe et al, 1997;Yuan and Greene, 2000b).…”

mentioning

confidence: 99%

Partial Defoliation Can Decrease Average Leaf Size but Has Little Effect on Orange Tree Growth, Fruit Yield and Juice Quality

Yuan¹,

Alférez²,

Kostenyuk³

et al. 2005

HortSci

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The effects of 2 consecutive years of annual defoliation during the harvest season on fruit size, yield, juice quality, leaf size and number were examined in trees of the midseason cultivar `Hamlin' and the late-season cultivar `Valencia' orange [Citrus sinensis (L.) Osb.]. In `Hamlin', removal of up to 50% of the leaves in late November had no effect on fruit yield, fruit number, fruit size, soluble solids yield, juice °Brix, and °Brix to acid ratio of juice the following year. In `Valencia', removal of 50% of the leaves in late March decreased fruit yield and soluble solids yield but did not affect Brix or the Brix to acid ratio of the juice. Leaf size of new flush was reduced by removal of 50% of the leaves in both cultivars but there was little effect on total canopy size. There were no measured effects of removing 25% of leaves from tree canopies. Thus, canopy growth, fruit yield, fruit quality, and leaf size were not negatively impacted when annual defoliations did not exceed 25% of the total canopy leaf area in `Valencia' and `Hamlin' orange trees for two consecutive years. Overall, fruit weight increased linearly with increasing ratio of leaf area to fruit number, suggesting that fruit enlargement can be limited by leaf area.

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“…In the present study, temperatures on the day of application and for the following 3 d were >21 ºC except for 2001, when temperatures were 19 and 16 ºC the day of and the day after treatment (Table 1); that year ethephon signifi cantly reduced yield (Table 5). Byers et al (1990) showed that chemical thinners may be more active during periods of low light, but solar radiation was relatively high for all experiments in the present study except for 2002, when yield per tree, number of fruit harvested per tree and crop density were not affected by treatment. Thinning spur 'Deli-ciousʼ has been inconsistently affected by fruit size at the time of treatment.…”

Section: Discussionmentioning

confidence: 46%

Combinations of Ethephon and Accel for Thinning `Delicious' Apple Trees

Marini¹

2004

jashs

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For 4 years, `Redchief Delicious' apple [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] trees were treated with ethephon and/or Accel (6-BA + Gibberellins 4+7) when average fruit diameter was 5.0 to 11.4 mm. Effective thinning was obtained with ethephon at concentrations >500 mg·L-1 and with Accel at concentrations of 100 to 125 mg·L-1. In only 1 year out of 4 did combinations of Accel plus ethephon reduce fruit set more than either material applied alone. Repeat applications of either material alone or in combination reduced fruit set no more than single applications. Fruit weight was negatively related to the number of fruit per tree. After adjusting fruit weight for number of fruit per tree at harvest with analysis of covariance, ethephon did not improve fruit weight at harvest, but Accel improved fruit weight in two of three experiments. The effect of combinations of Accel and ethephon on fruit weight was inconsistent. Chemical names used: 2-chloroethyl phosphonic acid (ethephon); polyothyethylleneploypropanol dihydroxy-propane 2, butoxyethanol (Regulaid); N-(phenylmethyl)-1H-purine-6-amine plus giberrellins A4 + A7 (Accel).

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Thinning of Spur `Delicious' Apples by Shade, Terbacil, Carbaryl, and Ethephon

Cited by 49 publications

References 8 publications

Carbohydrate and ethylene levels related to fruitlet drop through abscission zone A in citrus

Carbohydrate and ethylene levels related to fruitlet drop through abscission zone A in citrus

Partial Defoliation Can Decrease Average Leaf Size but Has Little Effect on Orange Tree Growth, Fruit Yield and Juice Quality

Combinations of Ethephon and Accel for Thinning `Delicious' Apple Trees

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