Gas exchanges and biochemical analysis in watermelon varieties under organic cultivation in the semi-arid

Abstract

The objective of this work was to evaluate, on a temporal scale, the effects of doses of biofertilizer on the variables related to gas and biochemical exchanges in three varieties of watermelon in organic cultivation in the semiarid region. The experiment was conducted in the Bebedouro (CEB) experimental field of EMBRAPA Semiarid in Petrolina-PE, in experimental design was in randomized blocks, in a factorial scheme in sub-divided plot (3x6x3), containing in the plots three varieties of watermelon (Explorer; Red Heaven, and Majestic); in the subplots six doses of biofertilizer (0; 80; 160; 240; 320 and 400 mL plant^-1) and in the subsubplots three collections throughout the crop cycle (30, 45 and 60 DAS), with four replications. The intermediate doses, between 120 and 250 mL plant^-1, of the biofertilizer provided the best values ​​of photosynthesis, stomatal conductance, transpiration, total soluble sugars and activity of the enzyme nitrate reductase in the watermelon varieties, especially the Explorer variety. Gas exchange and biochemical parameters were higher in the initial and intermediate phases of the cultivation cycle, 30 and 45 days after sowing.