The objective of the present study was to assess productive responses of beetroot cropped under natural conditions and under low tunnel covered with black net during the summer. The experimental design was a randomised complete-block arranged in a split-split-plot with 4 replications. The primary factor was cropping environment (protected and natural conditions), the secondary factor was beetroot cultivars (Itapuã 202 and Tall Top Early Wonder) and harvest time (13, 26, 39, 52 and 65 days after the transplant) was the tertiary factor. The characteristics assessed were the number of leaves, fresh and dry phytomass of leaves, fresh phytomass of tubers, leaf area index, plant height and presence or absence of white concentric lines in the tubers at each harvest time. Sensors were installed to measure photosynthetically active radiation and air temperature. Beetroot crop under tunnel resulted in lower fresh phytomass of the tuber and greater fresh phytomass of leaves when compared to the natural environment. The use of tunnel with black shade 70% did not show advantage over cultivation under natural environment in relation to production characteristics and beetroot qualities.
Beta vulgaris; tunnel; shade cover; radiation; temperature
