Impact of varieties and production methods on yield and vitamin C content in winter lettuce produced under greenhouse conditions

Abstract

This paper describes the effects of different varieties and production methods on yield and vitamin C content in lettuce leaves produced in the winter period. A threeyear study was conducted in a randomized block design under greenhouse conditions without additional heating. The trial included three varieties of lettuce (‘Archimeds RZ’, ‘RZ Santoro’, ‘Kibo RZ’). Each row planted with these varieties was exposed to the following covering treatments: control treatment on bare soil, pre-sowing mulching with PE-black foil, post-planting covering with agro textile (17 grams), a combination of mulching + agro textile. The results show that the different methods of production affected the yield of lettuce. The highest yield was recorded in the agro textile treatment (14 kg/10 m²), and the lowest in the control (9.31 kg/10 m²). Throughout the three years of the trial, it was continuously evidenced that ‘Santoro’ had the biggest heads and the highest yield (15.33 kg/10 m²), suggesting that the yield of lettuce is a varietal characteristics. Vitamin C content was found to differ, depending on the method of production, i.e. on the covering treatment applied. In average, the mulching + agro textile combination (26.77 mg/100 g) had the highest content while the control treatment had a significantly lower vitamin C content (21.10 mg/100 g).