บทคัดย่องานวิจัย

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Growth and productivity of vigorous 'Northern Spy'/MM.106 apple trees in response to annually applied growth control techniques.

Elfving, D. C.; Cline, R. A.;

Journal of the American Society for Horticultural Science Year: 1990 Vol: 115 Issue: 2 Pages: 212-218 Ref: 57 ref.

1990

บทคัดย่อ

Growth and productivity of vigorous 'Northern Spy'/MM.106 apple trees in response to annually applied growth control techniques.

Beginning in 1982, daminozide (DZ) was applied annually for 5 years to whole, 5-year-old trees: (a) shortly after bloom, (b) together with ethephon (ETH) 6 to 7 weeks after bloom or (c) after harvest. Controls were unsprayed. One-half of the trees receiving each growth regulator treatment was summer-pruned after terminal-bud formation each year. Postharvest DZ reduced shoot numbers, mean shoot length, trunk enlargement and fruit size, but had little or no effect on bloom, fruit set or yield. Postbloom DZ, summer DZ plus ETH, and summer-pruning reduced vegetative growth and time required for dormant-pruning, but only postbloom DZ and summer DZ plus ETH increased spur density in the tree. Postbloom DZ and summer DZ plus ETH increased both flowering and cropping in 3 of the 5 years, with little effect on fruit set. Fruit size was reduced only in years when cropping was enhanced. Total yields (1982-86) were increased by 34 and 36% by postbloom DZ and summer DZ plus ETH, respectively. Summer-pruning had no effect on fruit size in any year, but reduced yields in 1984 and 1986. Year-to-year fluctuation in yield was unaffected by any treatment. Growth-control treatments had no direct effect on foliar or fruit macronutrient concentrations.