Irrigation of radish cultivars in the region of Viçosa, Minas Gerais, Brazil

ABSTRACT The region of Viçosa in Brazil stands out for vegetable production. For success in this activity, the correct choice of cultivar with the correctly applied irrigation are necessary. As such, the aim of this study was to evaluate the agronomic performance of radish cultivars submitted to different irrigation depths. The radish crop was grown in a protected environment over three cycles, for periods of 38 to 40 days. The experimental design was of randomised complete blocks in split plots with five replications, comprising five irrigation depths (50, 75, 100, 125 and 150% of crop evapotranspiration-ETc) in the plots, with three radish cultivars in the subplots. (Hybrid no 25 - Sakata, Crunchy Royale - Sakata and Vip Crimson - Feltrin). A drip irrigation system was used, with the ETc obtained by means of the GESAI method. The following parameters were evaluated: root depth, plant water potential, leaf temperature, leaf weight, root diameter and length, number and weight of commercial and non-commercial roots, and water use efficiency. Since the experimental soil presented high water retention and availability, greater than 1.8 mm cm-1, an irrigation depth of 50% ETc is recommended, provided that the soil is at field capacity at the start of the cycle. When considering productivity and quality, the Crunchy Royale cultivar is recommended when cultivating the radish in Viçosa, Brazil.摘要 巴西维索萨（Viçosa）地区以蔬菜生产著称。要保障该产业的成功，需正确选择栽培品种并合理应用灌溉技术。为此，本研究旨在评估不同灌溉深度下萝卜品种的农艺表现。本试验在保护地环境下开展，共完成3个生长周期，周期时长为38至40天。试验采用裂区随机完全区组设计，设置5次重复：主区包含5个灌溉梯度，分别为作物蒸发蒸腾量（crop evapotranspiration, ETc）的50%、75%、100%、125%及150%，副区则设置3个萝卜品种，即杂交种25号（Hybrid no 25）——坂田（Sakata）、Crunchy Royale——坂田（Sakata）以及Vip Crimson——Feltrin。试验采用滴灌系统，通过GESAI方法获取ETc。本研究测定的指标包括：根深、植株水势、叶温、叶重、块根直径与长度、商品与非商品块根的数量及重量，以及水分利用效率。鉴于试验土壤持水性与供水能力较强，达1.8 mm·cm⁻¹以上，若种植周期初始阶段土壤处于田间持水量状态，则推荐采用50% ETc的灌溉深度。综合产量与品质表现，在巴西维索萨地区开展萝卜种植时，推荐选用Crunchy Royale品种。