EFFECTS OF GLYPHOSATE SUBDOSES ON GERMINATION OF WATERMELON (Citrulus lanatus) SEEDS

Abstract

Introduction: Although watermelon is a very important crop for the Acrean region, there are not many studies reporting the use of herbicides in it. This culture is sensitive to growth inhibitory herbicides when applied at commercial doses; However, little is said about the use of underdoses in watermelon production. Objective: The objective was to evaluate the germination and initial development of watermelon seeds submitted to different glyphosate underdoses. Material and methods: The experiment was carried out in a phytotechnic laboratory located at the Federal University of Acre (UFAC), Campus Floresta, in the municipality of Cruzeiro do Sul-AC, from December to January 2018. Fully randomized design (DIC), with 5 treatments and 4 repetitions, totaling 500 sample elements. The treatments consisted of the application of glyphosate underdoses in the following concentrations: 0 (T0); 4.5 (T1); 9 (T2); 18 (T3) and 36 (T4) g.a.ha-1. Over germiest leaves, saturating them. Twenty-five watermelon seeds were distributed over the germiest leaves. Evaluations were performed at 2-day intervals for a total of 10 days. The data were submitted to analysis of variance (ANOVA), at a significance level  = 0.05, when previously assumed the assumptions for its application, such as normality of errors and homogeneity of variances and regression analysis. Results: The sub-doses that caused the best significant effects for the evaluated variables were the Witness and T1 with 0 to 4.5 g e.a.ha-1 respectively. Final considerations: It was concluded that underdoses greater than 4.5 g e.a.ha-1 caused inhibition of watermelon plant development.