Performance of crisphead lettuce cultivars under protected environment in different times of production

ABSTRACT The objective of this work was to evaluate the behavior of Crisphead lettuce as a function of production seasons under different forms of protected environment. Two experiments were carried out in the field at different times: September to December 2017 and June to August 2018, in a randomizaed blocks desing, in a 4 x 7 factorial scheme, the first one being production environments under shade nets: red screen, chromatinet® screen, black screen and full sun, and the second, lettuce cultivars: Winslow, Irene, Balsamo, Rafaela, Iron Wood, Great Lakes and Delícia. The harvest was carried out at forty-two days after transplanting, where the following variables were analyzed: stem length (cm), total production and commercial productivity (t ha-1). The data were submitted to analysis of variance, and a joint analysis was performed to analyze the treatments effect, then the means were compared by the Scott-Knott test, at 5% probability. The microclimate was altered in the shaded beds, which affected the cultivars development. The cultivation in protected environment provides higher productivity of Crisphead lettuce from September to December, at that time the cultivars Balsamo and Delicia were highlighted under chromatinet®. In the period of mild temperatures, a better performance was observed for cv. Balsamo in full sun.

摘要
本研究旨在评估不同保护地栽培模式下，脆叶结球莴苣（Crisphead lettuce）的生长表现随生产季的变化规律。试验于2017年9月至12月、2018年6月至8月分两期在田间开展，采用随机区组设计，设置4×7析因试验方案：第一因素为遮阳栽培环境，包含红色遮阳网、chromatinet®遮阳网、黑色遮阳网及全光照4个水平；第二因素为莴苣品种，涵盖Winslow、Irene、Balsamo、Rafaela、Iron Wood、Great Lakes及Delícia共7个品种。于移栽后42天进行收获，测定的性状指标包括茎长（单位：厘米）、总产量与商品产量（单位：吨·公顷⁻¹）。对数据进行方差分析，并通过联合分析评估处理效应，随后采用斯科特-诺特检验在5%显著水平下开展多重比较。遮阳栽培床内的小气候发生改变，进而影响各品种的生长发育。9月至12月期间，保护地栽培可获得更高的脆叶结球莴苣产量，其中Balsamo与Delícia品种在chromatinet®遮阳网下表现突出。在温度温和的时段，全光照条件下的Balsamo品种表现更佳。