ISHS Acta Horticulturae 463: VIII International Symposium on Plant Bioregulation in Fruit Production
SYNTHETIC AUXINS EVALUATION ON FRUIT SIZE AND YIELD IN ‘ELLENDALE’ TANGOR |
| Authors: | A. Gravina, H. Arbiza, A. Bozzo, E. Laserre, M. Arias, F. Ronca |
| Keywords: | fruit growth, fruit weight, growth regulators, productivity, thinning |
| Abstract:
Fruit size is one of the characteristics of external quality, with greatest incidence on the commercial value of a citrus crop. Tangor 'Ellendale', one of the main cultivars in the group of mandarins in Uruguay, has shown a tendency to reduce fruit size in years of medium to high production, increasing fruit discard percentage. Three different experiments, two singles and one combined, were conducted to evaluate the effect of 3 5,6-trichloro-2-pyrydil-oxyacetic acid (3,5,6-TPA, 10 and 20 mg.l-1) and butylglycolic ester of 2,4-dichlorophenoxypropionic acid (2,4-DP, 37.5, 75.0 and 150.0 mg.l-1) sprays, at the end of physiological fruit drop and 15 days later, in fruit growth and final size, fruit number and yield of 'Ellendale'. Strong fruit drop was observed with 3,5,6-TPA sprays in two experiments; some differences due to auxin concentration and spray date were observed. Mean fruit size was increased in all the treatments but yield was reduced significantly in one experiment with this auxin. Different response was verified with 2,4-DP; neither of the evaluated parameters was affected, independently of spraying date or concentration used. After these results, it is possible to conclude that, under mean producing conditions of 'Ellendale' in Uruguay, treatments with these auxins are not to be recommended given the poor results that can be expected. | |
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