Growth and physiological response of coffee seedlingsruela,treatedv. M. et awith fungicides

Abstract

Research has shown that, in addition to the fungicidal action already known, strobilurins have positive physiological effects on the yield of some crops. Boscalid has also shown positive effects on plants, applied together or associated with strobilurin. The objective in this study was to evaluate the effect of fungicide application on growth and physiological behavior of coffee seedlings. The experimental design was in randomized blocks, with five replicates. There were five treatments: T1-Control, T2-Boscalid, T3-Pyraclostrobin, T4-Boscalid+ Pyraclostrobin and T5-Azoxystrobin applied in coffee seedlings. The application was at the “orelha de onça” stage (two round-shaped leaves), repeated every 15 days, counting 5 applications in total. Were evaluated shoot length, root length, stem diameter, shoot and root fresh matter, shoot and root dry matter, leaf photosynthesis, stomatal conductance, transpiration, intercellular CO2 concentration, water use efficiency and carboxylation efficiency. The application of fungicides promotes greater vegetative growth of coffee seedlings due to increased CO2 assimilation rate, reduced transpiration rates and increased water use efficiency, associated to the increased levels of auxin and cytokinins in leaves.