VEGETATIVE STAGE OF STRAWBERRY DURATION DETERMINED BY THE CROP YEAR

ABSTRACT Over the years, strawberry growth has shown alterations in its phenology, involving mainly the beginning of flowering and fruiting. The aim of this study was to verify whether the growth years influence the duration of strawberry vegetative and reproductive stages in protected environment. The development of the Camarosa strawberry cultivar was observed between 2007 and 2014. The crops were settled in a greenhouse in the Horticulture Sector at the University of Passo Fundo, RS. Data like transplant date, in the beginning and end of the fruits harvest; temperature data (maximum, average and minimum) were recorded in the growth environment. These data were used for the thermal sum calculation (daily, accumulated). The data analyses were carried out in a descriptive manner, relating the temperature data with the phenological stage of each year. The accumulated thermal sum that is necessary to begin the harvest was variable throughout the years, where it was between 383 and 438 degrees days-1 for plants with interval between transplant and harvest of 73 days (2008 and 2009) at 816 degrees days-1, where the interval was 111 days (in 2014). In the first case, it accumulated 5.2 ºC/day, in 2008 and 6 ºC/day, in 2009. In the second case, it was 7.3 ºC/day, in 2014. Seedlings which were transplanted in the first fortnight of May began fruiting in the beginning of August and September. Seedlings transplanted in July 2011 and 2012 began fruiting in similar periods, that is, in the first and second fortnight of September. It was found that, because of the temperatures recorded in different periods of growth and transplant time, there is alteration mainly in the strawberry vegetative stage.

摘要 多年来，草莓的生长物候（phenology）发生了改变，主要涉及开花与坐果的起始阶段。本研究旨在验证保护地栽培环境下，生长年份是否会影响草莓营养生长与生殖生长阶段的时长。研究于2007至2014年间，对‘卡玛罗莎’（Camarosa）草莓品种的生长发育情况进行了观测。试验作物种植于巴西南里奥格兰德州（RS）帕索丰杜大学（University of Passo Fundo）园艺学部的温室中。研究记录了定植日期、果实采收的起止时间，以及栽培环境内的温度数据（最高温、平均温与最低温）。上述数据被用于每日与累积积温的计算。数据分析采用描述性统计方法，将温度数据与各年份的物候阶段进行关联分析。启动采收所需的累积积温在各年份间存在差异：当定植至采收的间隔天数为73天时（2008年与2009年），累积积温介于383至438度日（℃·d）；而当间隔天数为111天时（2014年），累积积温达816度日。其中，2008年的日均积温为5.2℃·d，2009年为6.0℃·d，2014年则为7.3℃·d。于5月上半月定植的秧苗，于8月初和9月初进入结果期。2011年与2012年7月定植的秧苗，结果始期较为相近，即9月的上半月与下半月。本研究发现，由于不同生长阶段的温度条件与定植时间存在差异，草莓的物候变化主要体现在营养生长阶段。