Evolution of quality parameters of different lettuce (<i>Lactuca sativa</i> L.) varieties under unheated plastic tunnel

Abstract The plastic tunnel can ensure a positive effect on the yield and quality of vegetables. In our experiment, we evaluated following types varieties lettuce – heading type (‘Great Lakes 659’, ‘King May’), non-heading (‘Lollo Rossa’, ‘Lollo Bionda’), cos (‘Romaine lettuce’). highest head weight was detected in ‘Great 659’ (373.97 g plant −1 ) ‘Romaine lettuce’ (266.79 under an unheated springtime. Higher nitrate content (565.0 mg kg measured for ‘cos lettuce’, while lower values (425.50 were Bionda’. Among varieties, one dry matter also (8.52%). According to results production, as having higher accumulation.