WATERMELON INITIAL GROWTH UNDER DIFFERENT HYDROGEL CONCENTRATIONS AND SHADING CONDITIONS

Breno De Jesus Pereira,Franciele Medeiros Costa,Gustavo Araújo Rodrigues,Gilvanda Leão Dos Anjos,Anacleto Ranulfo Dos Santos

doi:10.1590/1983-21252019v32n407rc

Abstract

ABSTRACT Watermelon (Citrullus lanatus) belongs to the plant family Cucurbitaceae. It is cultivated in many regions of Brazil, particularly in rainfed areas; thus, it is subject to the problems arising from irregular rainfall. Hydrogel is a soil conditioner used to retain and provide water to plants for long periods of time. Therefore, incorporating hydrogel into the soil should increase water availability for watermelon cultivation, and may be an alternative method to reduce the risk of water deficit. This study evaluated the effect of different concentrations of hydrogel on the initial growth of watermelon cv. 'Crimson Sweet' under different shading conditions. The experiment was carried out in a greenhouse with completely randomized design with a 4×3 factorial scheme. The treatments consisted of four hydrogel doses (0.0; 1.5; 3.0; and 6.0 g L-1 substrate), three shading conditions (under full sun; black shade net, and red shade net, both with 50% shading), and five replicates per treatment. The variables evaluated were plant height; stem diameter; shoot, root, and total dry matter; and leaf area. The best hydrogel dose for watermelon cultivation was 1.5 g L-1, but the higher doses impaired plant growth, regardless of shading conditions. The black net improved biomass accumulation in 'Crimson Sweet' watermelon, whereas the red net induced plant etiolation.

Highlights

Watermelon (Citrullus lanatus) is a cucurbit cultivated in various regions of Brazil and accounts for around 105,491 ha of cultivated land
There was isolated effect of shading condition and hydrogel dose on plant height; stem diameter; root length; shoot, root, and total dry weight; and leaf area of ‘Crimson Sweet’ watermelon plants
The stem diameter of plants under full sun was larger than the stem diameters of the plants grown under black and red net shading (Table 1) at 1.5 g L–1 hydrogel and black net shading at 3.0 g L–1

Summary

INTRODUCTION

Watermelon (Citrullus lanatus) is a cucurbit cultivated in various regions of Brazil and accounts for around 105,491 ha of cultivated land. The largest producing states in the country are Rio Grande do Sul (346,310 tons), São Paulo (291,846 tons), Goiás (267,896 tons), Bahia (239,177 tons), and Tocantins (232,907 tons) (IBGE, 2018) The cultivation of this vegetable is of great economic and social importance because it is mainly carried out by family farmers. Some of the challenges faced by growers are producing quality fruits while maintaining high production levels throughout the year, which is difficult because watermelon is mainly grown in dryland areas (OLIVEIRA et al, 2015b). This means that it is subject to irregular rainfall, which influences its yield. This study evaluated the effect of different concentrations of hydrogel on the initial growth of watermelon under different shading conditions

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS