• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.445-451
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• 2012

The thinning effects of lime sulfur either alone or combined with fish oil on two apple cultivars 'Fuji'/M.9 and 'Hongro'/M.9 were investigated during two consecutive seasons. Either 1% or 2% lime sulfur at full bloom decreased the amounts of both terminal and axillary fruits compared with unsprayed 'Fuji' control trees in the first year. However, 1% or 2% lime sulfur did not decrease terminal fruit set in the second year. Only, triple applications of 1% lime sulfur significantly reduced the number of terminal and axillary fruits in both years. Multiple application of 1% lime sulfur was the most effective in thinning of 'Hongro'. In the first year, double or triple applications of 1% lime sulfur was effective in thinning terminal or axillary fruit, but one time applications of 1% or 2% lime sulfur was not reduced axillary fruit in 'Hongro' apple trees. In the second season, all treatments reduced terminal or axillary fruit in 'Hongro' clusters, except single application of 1% lime sulfur. Fish oil did not always improve the thinning effects of lime sulfur in 'Fuji' or 'Hongro' apple trees. None of treatments caused significant russeting in the harvested fruits. Most of thinning treatments had little effect on 'Fuji' or 'Hongro' fruit quality in terms of fruit weight, firmness, soluble solids concentration or titratable acidity.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.1-5
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• 2012

This study was conducted to elucidate the cause of micro-cracking in the exocarp of 'Jinmi' peach (Prunus persica). through the microscopic observation of fruit skin development in 4 varieties such as 'Jinmi', 'Kanoiwa Hakuto', 'Kawanakajima Hakuto', and 'Yumyeong'. Micro-cracking was noted in 59.1% of 'Jinmi', 30.6% of 'Kanoiwa Hakuto', 21.5% 'Kawanakajima Hakuto' and 6.4% of 'Yumyeong', respectively. The development of intercellular spaces, which increased rapidly with the fruit development, was easily observed at 69 days after full bloom. Histological studies revealed that the number of outer epiderm cell layers of 'Jinmi' was smaller than that of the other three cultivars, and thinner than the 'Kawanakajima Hakuto' and 'Yumyeong'. Moreover, 'Jinmi' exhibited smaller and flatter shapes in the sub-epidermal cell layer than those of the 'Kawanakajima Hakuto' and 'Yumyeong' at harvest season. Therefore, these results suggest that micro-cracking of 'Jinmi' fruit skin was due to poor-developed outer epidermis and well-developed intercellular spaces just under exocarp as compared with other varieties.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.577-583
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• 2014

Benzyladenine (BA, 99% purity), MaxCel$^{(R)}$ (1.9% BA), Fruitone (3.5% NAA), MaxCel$^{(R)}$ + Fruitone, a nd s imazine were applied postbloom as fruitlet thinning agents to mature 'Hongro' and 'Fuji' apple (Malus domestica Borkh.) trees. BA and MaxCel$^{(R)}$ were applied at $100mg{\cdot}L^{-1}$ a.i. while Fruitone at $0.1mg{\cdot}L^{-1}$ a.i. and simazine at $400mg{\cdot}L^{-1}$ a.i. All PGRs were applied at 8 days after full bloom (DAFB, 6 mm fruit diameter) in both cultivars, while simazine was treated twice at 7 and 14 DAFB. In 'Hongro', the number of total fruit set per flower cluster in terminal buds was 1.67, 1.84, and 1.81 in MaxCel$^{(R)}$ + F ruitone, MaxCel$^{(R)}$, and simazine applications, respectively, when compared with 2.35 of water control. These reductions in fruit set were mainly attributed to the increased ratio of defruited clusters by the thinning agents. In 'Fuji' apple, the number of total fruit set per flower cluster in terminal buds was 1.29, 1.60, and 1.76 in MaxCel$^{(R)}$ + Fruitone, Fruitone, and MaxCel$^{(R)}$, respectively, when compared with 2.56 of water control in 'Fuji' apple. The addition of Fruitone to the MaxCel$^{(R)}$ promoted the thinning efficacy in both cultivars, compared to MaxCel$^{(R)}$ only. The thinning efficacies were similarly observed with lateral flowers in both cultivars. A significant increase of fruit weight by the postbloom thinning treatments was observed only in the BA application in 'Hongro', while the effect was observed in BA and MaxCel$^{(R)}$ in 'Fuji'. While the soluble solids content increased in the BA, MaxCel$^{(R)}$ and MaxCel$^{(R)}$+Fruitone treatments in both cultivars, other fruit quality attributes were not affected by the application of post-bloom thinning agents.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.24-31
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• 2016

This study investigated the effects of flower and fruit thinning agents on fruit set and harvested fruit quality attributes in 'Gamhong' apples. Lime sulfur, MaxCel (1.9% BA), and Fruitone (3.5% NAA) were applied either at post-bloom or fruitlet stages to mature 'Gamhong/M.9' trees. In 2011, the numbers of fruits per cluster in terminal flowers were 1.74, 0.82, and 1.15 for the control, lime sulfur, and Maxcel (applied at 10-mm fruit stage) treatments, respectively. The percentages of single fruit per cluster were 36.0, 47.9, and 48.7% for the control, lime sulfur, and Maxcel (10 mm) treatments, respectively, while the percentages of clusters with three fruits per cluster were 22.9, 1.4, and 5.8%. In lateral flowers, fruit numbers per cluster were 1.20, 0.36, and 0.50 for the control, lime sulfur, and Maxcel (10 mm) treatments, respectively. In 2012, all the thinning treatments showed a positive effect on flower and fruit thinning, compared with the control. Moreover, the treatment with thinning agents did not affect fruit quality. Overall, the results suggest that a single application of flower or fruit thinning agents would be sufficient, rather than the mixed application of thinning agents, based on the observed decrease in fruit setting.