Eficiência no uso da água na produção de mudas de genótipos de pitaieira

Abstract

Different factors can limit the initial growth of pitaya seedlings, emphasized the scarcity of water. Therefore, the objective of this study was to evaluate the effect of water deficit factors, water depth and irrigation shifts, on the growth of pitaya genotype seedlings in an environment. In this research, three experiments were carried out in the experimental area of Universidade Estadual do Oeste do Paraná, campus Marechal Cândido Rondon. In the first experiment, the design used was completely randomized, arranged in a 2x4x2 triple factorial scheme, with two dragon fruit genotypes, four days of evaluation (15, 30, 45, 60 days) and with and without irrigation. After acclimatization, they were subjected to water deficit and evaluated at the end of periods of 15, 30, 45, 60 days and subjected to determination of relative water content, height, diameter, fresh mass of the aerial part, dry mass of the aerial part and root, in addition to biochemical analyses, including proline, total soluble sugars. The water deficit negatively influenced the height, diameter, fresh mass of the aerial part, dry mass of the aerial part and dry mass of the root, which had lower growth after 60 days without irrigation. In the second experiment, a completely randomized design was used, in a 2 x 5 factorial scheme. The first factor consisted of two dragon fruit genotypes and the second factor consisted of five irrigation depths, including, without irrigation, 25, 50, 75 and 100% of the actual irrigation required. The evaluations began 60 days after planting, collecting data on the variables plant height, plant diameter, number of cladodes, length of cladode 1, length of cladode 2, diameter of cladode 1, diameter of cladode 2. After 150 days of implementation of the experiment, fresh mass of the aerial part, dry mass of the aerial part, length of the largest root and dry mass of the root were obtained. The different irrigation depths significantly influenced the height, plant diameter and plant height, fresh mass of the aerial part, dry mass of the aerial part, obtaining the highest averages when the depths 75 and 100% were applied. In the third experiment, a completely randomized design was used, in a 2 x 6 factorial scheme, with the factors being two dragon fruit genotypes and six irrigation shifts, which occurred at 48, 96, 144, 192, 240 and 288h. The interaction between genotype factors and irrigation shifts was significantly changed for most of the variables evaluated, namely, height, cladode sum length, fresh mass of the shoot, dry mass of the shoot, dry mass of the root, total dry mass, length of the largest root. The irrigation shifts that provided the greatest gains for these variables were 48 h for genotype 1 and 96 h for genotype 2.