|Authors: ||F. Camacho Ferre, E.J. Fernández Rodríguez, M. Díaz Pérez|
|Keywords: ||citokinins, auxins, 2,4 dichlorophenoxyacetic acid, 1-(2-chloro-4-pyridyl)-3-phenylurea, plant growth regulators, fruit setting.|
A trial was conducted growing diploid watermelon cv.
Sweet Marvel (S&G) without honeybee pollination in a typical ´parral´ greenhouse in Campo de Níjar, Almería, Spain.
The area of the trial was completely isolated by means of a photoselective 50 mesh anti-insect net.
The effects of two different plant growth regulators, 2,4 dichlorophenoxyacetic acid (2,4 D) (amine salt) and forchlorfenuron [1-(2-chloro-4-pyridyl)-3-phenylurea or CPPU] on yield and seedless fruit induction were analysed.
Experimental design consisted of completely randomised blocks.
Six treatments were used: 8, 12 and 16 ppm of 2,4 D, and 50, 100 and 200 ppm of CPPU. CPPU treatments were sprayed only over female flowers at two different moments whereas 2,4-D was sprayed over the entire plant in a single treatment.
Yield was significantly affected by the treatments.
As the dosage of 2,4 D increased yield was reduced, though the opposite trend was found when considering CPPU. The highest yield was found at 200 ppm CPPU with 5.14 kg m-2, and the lowest at 50 ppm CPPU. The highest proportion of seedless fruits was found in 200 ppm CPPU, 97.8 %, showing statistical differences with 50 and 100 ppm CPPU which only yielded 58.1 % and 60.2 % respectively, but not with any of the 2,4 D treatments.
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