Fitomassa da planta e caracterização físico-química de abóbora produzida com aplicação de citocinina e auxina.

Abstract

The culture of the pumpkin is of great economic and social expression in Brazil. However, its initial productive potential, as in most curcubitaceae, is dependent on proper pollination. Synthetic hormones are used in order to increase the yield of crops, especially those that act to stimulate fruiting, such as cytokinins and auxins. Since it is known that the pumpkin culture depends on pollinating agents and that these hormones can collaborate with parthenocarpic fruiting, it was objectified by means of this study induce fruiting in squash by means of different forms of application in the plant and combinations of cytokinin CPPU and auxin AIB. The work was carried out in the premises of the Agro-Food Science and Technology Center, Federal University of Campina Grande, Campus Pombal-PB, between the months of March and June 2018. Atlas pumpkin seeds were sown in Styrofoam trays of 128 cells for the production of seedlings and after reaching two final leaves, were transplanted in pots with a capacity of 2 L, filled with coconut fiber and Tropstrato HT Hortaliças® commercial substrate in the proportion 3: 1. The treatments were composed of six proportions associated with the growth regulators, corresponding to 0/0 (control); 0/100; 25/75; 50/50; 75/25; 100/0% of the concentrations 2.5 and 10.0 mg L-1 of CPPU/AIB, respectively, and of two forms of application: via ovary and foliar. The experimental design was a randomized block design, with four replications. At 72 days after transplanting (DAT), leaf pigment, growth and dry matter accumulation analyzes were performed in the plants: chlorophyll a, b, total and leaf carotenoids, leaf area, leaf number, stem diameter, number of leaves roots, root and root length, dry mass of leaves, branches, roots, fruits and total, the fruit growth and quality characteristics were also evaluated: fresh mass, bore diameter, neck diameter, and neck, firmness, soluble solids, titratable acidity, hydrogenation potential, total sugars, vitamin C, carotenoids and starch. It was concluded that the proportion 50/50% by foliar raises the content of carotenoids in the leaves. The proportions 25/75 and 50/50% applied by foliar route were the ones that favored plant growth parameters. The use of 0/100% via ovary stimulates the growth and accumulation of root mass, but does not promote fruiting. The proportions 50/50% via foliar and 75/25% via ovary, respectively, were the ones that increased the growth and fruit quality parameters. The application of CPPU via foliar in higher concentration in proportion (100/0%) decreases quality characteristics such as vitamin C, carotenoids and starch.