Giberelina e tempo de embebição na emergência e crescimento de plântulas de Melancieira Triploide.

Abstract

The triploid watermelon has been gaining more and more space in the fruit sales market in Brazil. One of the main problems faced by producers is the low percentage of seed germination, which directly influences their productivity. Therefore, this present work aims to evaluate the effect of gibberellic acid (GA3) concentration and water imbibition time on the emergence and growth of triploid watermelon seedlings. The experiments were carried out at the Laboratory of Plant Physiology and Vegetation House of the Academic Unit of Agrarian Sciences of the Center for Agro-Food Science and Technology at the Federal University of Campina Grande, campus of Pombal - PB, from 07/28 to 09/15/ 2021, using the watermelon hybrid 'Lola'. In experiment 1, treatments consisted of four concentrations of gibberellic acid (0, 200, 400, 800 mg L1). In experiment 2, the treatments consisted of four times of imbibition in water (0, 6, 12, 24 h). The experimental design used was completely randomized, with three replications, with 25 seeds each. After applying the treatments, the seeds were sown in polypropylene trays (styrofoam) with 128 cells containing commercial substrate Tropstrato HT Hortaliças® and placed in a greenhouse covered with plastic and 30% shade. The characteristics evaluated were: Percentage of germination at five and twelve days, emergence speed index, plant height, number of leaves, root length, dry mass of leaf, stem, root and total. The collected data were submitted to analysis of variance and regression. There was an increase in plant height and a reduction in the germination of watermelon seeds with the increase in the concentration of gibberellic acid. The other characteristics evaluated were not influenced by the application of gibberellin. For the soaking time, there was an increase of 23.3% in the number of plants emerged in 24 hours. According to the behavior of the results obtained in this research, we can conclude that gibberellin does not improve germination in triploid seeds and that the positive response to imbibition in water is related to physical limitations in the tegument, not yet possible to be clarified in this work.