Alternative rest-breaking agents to DNOC/oil for apples

North, M.S.

doi:10.1080/02571862.1992.10634600

Cited by 4 publications

(2 citation statements)

References 6 publications

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“…The rest-breaking properties of hydrogen cyanamide (HC) were tested in several species since the 1980s, but only later in apples (Shulman et 01., 1983). HC alone, and in combination with mineral oil, has shown positive results in apple trees (Petri et 01., 1990;North, 1992). HC and oil (1.25+3%), and 5% DNOC oil gave similar budburst and fruit set on four-year-old 'Golden Delicious' trees (North, 1992).…”

Section: Introductionmentioning

confidence: 99%

Effect of mineral oil and hydrogen cyanamide concentration on dormancy breaking in ‘Golden Delicious’ apple trees

Sagredo

Theron

Cook

2005

South African Journal of Plant and Soil

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South African production are!3S receive insufficient winter chilling for apple production, necessitating the use of artificial means to break dormancy_ Hydrogen cyanamide (HC) alone or in combination with mineral oil (oil) is used as a rest-breaking agent in many deciduous species. The effect of different concentrations of HC and oil on budburst, yield, fruit quality and vegetative growth of mature 'Golden Delicious' apple trees were evaluated; the objective was to determine the presence of interaction between the rest-breaking effect of HC and oil when combined at varied concentrations, and to determine appropriate concentrations of HC and oil, to enhance budburst, yield and fruit quality. Three trials were conducted in the Elgin valley (34 oS, 300 m) of the Western Cape, South Africa, in 1999 and 2000. The first trial evaluated four concentrations (0, 0.5, 1 and 2%) of Dormex® (hydrogen cyanamide 520 g·L-1 ) in combination with four concentrations of mineral oil (0, 1, 2, and 4%). The second trial used three concentrations (1, 2 and 4%) of Dormex® in combination with three concentrations of mineral oil (1, 2, 4%), plus an unsprayed control, and a treatment of 6% of DNOC Winter Oil®. The third trial included five treatments: 0.5% Dormex® + 3% oil, 1 % Dormex® + 4% oil, 6% DNOC Winter Oi/®, 6% oil and a non-sprayed contro/. All of the treatments were applied at the first visible signs of bud burst. No synergistic effect was observed between oil and HC. Mineral oil at 4% plus 1 to 2% Dormex® were sufficient to break dormancy. Dormex® at 4% (2.08% HC) reduced fruit set and yield.

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Section: Introductionmentioning

confidence: 99%

Effect of mineral oil and hydrogen cyanamide concentration on dormancy breaking in ‘Golden Delicious’ apple trees

Sagredo

Theron

Cook

2005

South African Journal of Plant and Soil

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“…Hydrogen cyanamide had been used frequently to break the dormancy in grapevine floral buds [12,13] besides, its use in other fruit species like kiwi, peach and other stone fruits [14,15]. Hydrogen cyanamide alone and in combination with mineral oil has shown positive results in apple trees [16,17] and enhanced fruit yield.…”

Section: Introductionmentioning

confidence: 99%

Residue Dynamics of Hydrogen Cyanamide and Ethephon in Apple

Ltd¹

2019

RAES

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In the present study, supervised field trials were conducted in Royal delicious variety of apple trees to evaluate the persistence of hydrogen cyanamide and ethephon during 2015-16 at different locations of Himachal Pradesh and Jammu & Kashmir. Standardised analytical methods simulated to the lab conditions were validated and adopted to find out the recoveries of hydrogen cyanamide and ethephon in apple fruits. Residues of hydrogen cyanamide were determined by HPLC-PDA with mobile phase comprising of methanol and water (2:8) following the application of Dormex 49% AS at the rate of 0.5% a.i., 1.0 % a.i. and 2.0 % a.i. during dormant stage of apple trees. Formulation of ethrel 39% SL was applied on fruit bearing trees close to harvest stage were determined as ethylene by head space analysis. Hydrogen Cyanamide residues were not detected in any sample right from walnut stage of apple after 85-111 days of treatment to the final harvesting between 179 -209 days irrespective of any location. It has been observed that spray application of ethephon caused early fruit drop therefore, samples from all the four locations were analysed up to 10 days. Initial deposits of ethephon as ethylene on apple fruits at Matiana and Thanedhar ranges between 2.044 -2.147 mg kg -1 and 4.036 -4.133 mg kg -1 which reduces between 0.056 -0.057 and 0.083 -0.088 mg kg -1 on day 10 due to the single and double dose application, respectively. Harvest time residues of ethephon in Youngora and Lassipors locations of J&K were 0.100 and 0.099 and 0.143 and 0.137 mg kg -1 at single and double dose, respectively. A safe waiting period of 5 days is suggested between ethephon application and fruit harvest to safeguard the consumer's health. No residues of hydrogen cyanamide were detected in fruits and hence, does not pose any threat to the consumers.

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