Photoperiod manipulation using supplemental lighting enables double-season production of hops (Humulus lupulus L.) under subtropical climatic conditions. In Florida, United States, the spring growing season (Spring) is from February to June, and the fall growing season (Fall) is from June to November. To develop the optimum trellis for this unique hop production system, we examined the effects of two trellis designs (straight trellis and V-trellis) and three trellis heights (3.7, 4.6, and 5.5 m) on growth, morphology, yield, and cone quality of 'Cascade' hops grown in west central Florida. The straight trellis had two twines per hill installed on a top middle cable, whereas the V-trellis had four twines per hill installed on two top parallel cables. We trained 16 bines per hill for both trellises. Data were collected during establishment years: Year 1 and Year 2. Yield showed significant season × trellis height interaction effects. Surprisingly, yield was highest in Year 1 Spring and decreased by 45–74 % in the subsequent seasons. Increasing trellis height from 3.7 to 5.5 m increased yield by 78–215 %. On average, the V-trellis produced 24 % higher yield than the straight trellis. The 5.5-m V-trellis produced the highest annual yield of 1807 kg ha–1 in Year 1. Yield had a significant positive correlation with stem dry weight in Year 1 Spring and Year 2 Spring, but it had no significant correlation with bine number per hill, stem diameter, and internode length in any season. Cone quality showed significant seasonal variations. Total α acid concentration decreased from Spring to Fall in both years and recorded the highest value in Year 2 Spring. Similarly, total essential oil content was highest in Year 2 Spring. Except in Year 2 Fall, total α acid concentration (5.35–8.25 %) was within or above the normal range for ‘Cascade’. Compared to these seasonal variations, trellis design and height effects on cone quality were relatively small. These results suggest that, during establishment years, adopting a V-trellis design and increasing trellis height can maximize yield in subtropical hop production without compromising overall cone quality. Ongoing research will validate these findings in mature hop plants.

中文翻译：

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亚热带气候下双季啤酒花 （Humulus lupulus L.） 生产的棚架设计和高度优化：建立期间的生长、形态、产量和球果质量


使用补充照明的光周期操作可以在亚热带气候条件下实现啤酒花 （Humulus lupulus L.） 的双季生产。在美国佛罗里达州，春季生长季节（Spring）为2月至6月，秋季生长季节（Fall）为6月至11月。为了为这种独特的啤酒花生产系统开发最佳棚架，我们研究了两种棚架设计（直棚架和 V 形棚架）和三种棚架高度（3.7、4.6 和 5.5 m）对生长、形态、产量和锥体质量的影响在佛罗里达州中西部种植的“级联”啤酒花。直格子每山有两根麻绳安装在顶部中间电缆上，而 V 型格架每山有四根麻绳安装在两条顶部平行电缆上。我们为两个棚架训练了每座山 16 个 bines。数据是在建立年份收集的：第 1 年和第 2 年。产量显示出显著的季节×棚高交互效应。令人惊讶的是，第 1 年春季的产量最高，随后的季节下降了 45-74%。将棚架高度从 3.7 m 增加到 5.5 m 可将产量提高 78-215%。平均而言，V 型棚架的产量比直棚架高 24%。5.5 米的 V 型棚架在第 1 年产生了 1807 公斤公顷-1 的最高年产量。1 年春和 2 年春产量与茎干重呈显著正相关，但与任何季节每山的 bine 数、茎粗和节间长均无显著相关性。蛋果质量表现出显著的季节性变化。α酸总浓度在这两年的春季到秋季都有所下降，并在第 2 年春季录得最高值。同样，第 2 年春季的总精油含量最高。除 2 年级秋季外，总酸浓度 （5.35-8） α。25 %）在或高于 'Cascade' 的正常范围内。与这些季节性变化相比，棚架设计和高度对蛋果质量的影响相对较小。这些结果表明，在建立年份，采用 V 型棚架设计和增加棚架高度可以最大限度地提高亚热带啤酒花生产的产量，而不会影响整体球果质量。正在进行的研究将在成熟的啤酒花植物中验证这些发现。