Combining ethephon and naphthalene acetic acid (NAA) in one spray to thin ‘Golden Delicious’ apples

摘要

Abstract A trial examined the effects of using ethephon or naphthalene acetic acid (NAA) alone or in combination to thin ‘Golden Delicious’ apples. All sprays were applied only at full bloom (FB). A factorial design was used with ethephon sprays of 0, 50, 100, and 200 mg/litre and NAA at 0, 5, 10, and 20 mg/litre with an additional treatment hand thinned just after FB. Ethephon applied alone thinned effectively at 100 or 200 mg/litre. NAA applied alone did not thin at any concentration. The three concentrations of NAA with ethephon at 50 mg/ litre improved thinning over the untreated control but not enough to significantly improve fruit weight and size. Ethephon alone at 100 mg/litre thinned very effectively and as well as any combination with NAA. Fruit weight and size were improved by all treatments using ethephon at 100 mg/litre. There was no advantage using ethephon at 200 mg/litre when compared to 100 mg/litre. Although there was some evidence that the combination of ethephon and NAA at the highest c...