Characteristics of the Fruits and Flesh Softening Delay Induced by GA3 and Thidiazuron (TDZ) Treatment in ‘Heukboseok’ Grape

Abstract

This research was conducted to investigate effect the plant growth regulators (PGRs) on the characteristics of fruit and flesh softening, using GA3 and thidiazuron (TDZ) treatments in 'Heukboseok' grapes. The total yield obtained under PGR treatment was 88.3% lower than the target production when a single treatment with GA3 of low concentrations was used, but the expected yield was recovered by combined treatment with TDZ and GA3. When harvested on the basis of color, the harvest rate up to 100 days after full bloom (DAFB) was low with the GA3 single treatment, but was increased by the addition of TDZ, with the second TDZ mixed treatment being particularly effective. The soluble solids content in the PGR-treated samples demonstrated no significant changes after 90 DAFB, while the acidity content decreased rapidly starting from 90 DAFB. Measured on the basis of sugar and acidity content, maturity was reached much earlier in treated fruit than in the non-treated fruit. Firmness was maintained at a higher level until the final harvest time after PGR treatment compared to untreated grapes according to epidermis thickness and flesh density increase to activity cell division and expansion by GA3 and TDZ. In particular, the fruit quality was improved based on the delay of softening in primary and secondary treatments of 25 mg･L -1 GA3 + 2.5 mg･L -1 TDZ. The production of seedless fruit was difficult, even with the inclusion of TDZ, reaching the highest seedless rate of only 65.5%. Fruit cracking was rare, occurring at a rate of about 0.0~0.9% in all treatments. Accordingly, 'Heukboseok' grapes should be harvested within 100 days after full bloom (DBFB) before a rapid decrease of firmness, conferred by primary and secondary treatments with 25 mg･L -1 GA3 + 2.5 mg･L -1 TDZ.Additional key words: harvest rate, fruit density, fruit softening, plant growth regulator

Combined treatment with gibberellic acid and thidiazuron improves fruit quality of ‘Red Dream’ grape cultivar

“…This is because the growth rate of the fruit is increased, but the maturation and ripening process is not necessarily accelerated. Additionally, the CPPU and TDZ can both delay the ripening process of grapes by suppressing the production of ethylene, which is a hormone that plays a crucial role in fruit ripening (Carvajal-Millan et al, 2001;Jung et al, 2015). In 'Flame seedless', coloration was greatly inhibited when cytokinin-type hormones were treated, which not only delayed the harvest period but also interfered with the production of marketable berries (Peppi and Fidelibus, 2008).…”

Effect of Thidiazuron on Terpene Volatile Constituents and Terpenoid Biosynthesis Pathway Gene Expression of Shine Muscat (Vitis labrusca × V. vinifera) Grape Berries

“…In apple, treatments with TDZ have been shown to alter the apple shape index and cause a reduction in the red surface of fruit and TDZ treatment also increased the percentage of fruit that were asymmetrical and exhibited calyx-end rot [20]. Plant endogenous hormone levels are regulated by TDZ and floriculture applications have shown a benefit for the inhibition of leaf yellowing of cut stock flowers by protecting leaf chlorophyll from degradation after transfer to vases [21]. Similarly, the immersion of grape berries in a TDZ solution resulted in higher quality fruit and increased firmness of fruit flesh [22].…”

Characteristics of the Fruit Quality and Volatile Compounds of ‘Cheongsoo’ Grape by Treatment with Different Plant Growth Regulators

“…Fruit characteristics of 'Cheongsoo' grape treated with different growth regulators 포도에 있어서 식물생장조절제 처리에 따른 과실 품질 및 휘발성 향기 특성 가용성 고형물(TSS) 함량은 무처리와 GA 3 100ppm 단용처리 사이에 1°Brix 정도의 차이가 났고, GA 3 100ppm + TDZ 5ppm과 GA 3 100ppm + FCF 5ppm PGR 혼용처리한 포도는 무처리나 GA 3 100ppm 처리와 차이가 나지 않아 cytokinin계 PGR 처리가 TSS 함량에 큰 영향을 미치지 않는 것으로 나타났다. 산함량은 무처리 포도가 PGR 혼용처리한 포도보다 0.15% 정도 유의하게 높게 나타났다 Jung et al(2015)…”