Efeito fisiológico do fungicida boscalida na atividade da nitrato redutase e nas características fitotécnias de pepineiro japonês enxertado e n?o enxertado.

摘要

The present study aimed to evaluate physiological effect of the fungicide boscalida in the activity of nitrate reductase in the plant parameters characteristics of Japonese cucumber grafted and non grafted. The experiment was carried out under protected cultivation at S?o Manuel Experimental Farm, Faculty of Agronomical Sciences ( FCA), S?o Paulo State University (UNESP), Botucatu Campus, S?o Paulo State, Brazil. Both the cucumber hybrid ‘Tsuyataro’ grafted onto the pumpkin ‘Excite Ikky’ and ungrafted plants were subjected to different levels (0, 25, 50, 75 and 100 g a.i. ha -1 ) of the boscalida fungicide through leaf application at weekly intervals. Experimental design was in randomized blocks, in a 5x2 factorial arrangement, with four replicates and six plants per plot, so that the four central plants were considered in the evaluation. Higher activity of nitrate reductase was observed in grafted plants and a linear response according to the fungicide level was detected at 81 D.A.T. There was also a linear effect according to the fungicide level for leaf area and plant dry matter and there was no difference between plant types . On the other hand, the two highest levels led to increased number of commercial, non-commercial and total fruits. G rafted plants had higher non-commercial production, but with no difference relative to commercial and total production. The lowest levels together with the treatment without boscalida had the lowest productivities. Conversely, the two highest levels led to an increase in commercial, with increases of 15.90 and 62.37% relative to the treatment without boscalida. In conclusion, the physiological effect of boscalida was obtained by using the levels 75 and 100 g a.i. ha -1 in both grafted and ungrafted cucumber plants.