The evaporative cooling effects of overtree microsprinkler irrigation on ‘Mondial Gala’ apples
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- 作者：Iglesias ; Ignasi ; Salvia ; Jordi ; Torguet ; Laura ; Montserrat ; Ramó ; n
- 关键词：Apple ; Gala ; Anthocyanin ; Colour ; Overtree cooling ; Microsprinkler ; Temperature ; Fruit quality ; Economical performance
- 刊名：Scientia Horticulturae
- 出版年：2005
- 出版时间：January 30, 2005
- 年：2005
- 卷：103
- 期：3
- 页码：267-287
- 全文大小：598 K
文摘
Microsprinkler irrigation for evaporative cooling of ‘Mondial Gala’ apples (Malus x domestica Borkh.) was evaluated over a 3-year period in Lleida (NE Spain). Cooling irrigation was applied continuously for 2h on a daily basis for 25–30 days prior to commercial harvest. Three treatments were evaluated: (1) control without overtree microsprinkler irrigation; (2) microsprinkler irrigation applied at sunset; (3) microsprinkler irrigation applied at mid-day (year 2) or at sunrise (year 3). Fruit and orchard temperature were significantly reduced by cooling irrigation, especially when applied at mid-day and at sunset. Fruit colour, as measured with a Minolta CR-200 portable triestimulus colourimeter using the CIE [1976] L*a*b* system, and anthocyanin concentration were significantly affected by both the cooling irrigation and the weather of each specific year. The years 1998 and 1999 were warm years typical of the region and cooled fruits had better colour than in the control. In 1997, on the other hand, low temperatures and rainfall prior to harvest masked the effects of cooling irrigation on fruit colour and quality parameters. Microsprinkler irrigation, especially when applied at sunset, increased the red colour, providing greater surface colouration and higher anthocyanin content on both sides of the fruit. A linear regression of anthocyanin content on L*, a*/b* ratio and hue angle provided R2 values of 0.58, 0.52 and 0.58, respectively. These values are low for estimating fruit anthocyanin content in situ from chromaticity values. Based on the colour required to meet EU grade standards, 13–22 % more fruits were harvested at first pick from trees receiving cooling irrigation than from the control.