In west–central Florida, strawberries (Fragaria ×ananassa Duch.) are harvested from early December to late March. The peak harvest occurs at the end of the season and lasts ≈1 month, usually from late February to mid-March. As the peak harvest progresses and temperatures increase, fruit become smaller and the soluble solids content (SSC) of fruit declines. The main objective of this study was to determine whether the progression of peak harvest results in a decline in SSC independent of temperature. In 2007 and 2008, recently opened flowers were tagged in the field on the first week into the peak bloom (WPB) and for 3 additional weeks thereafter. Three days after tagging, plants were transplanted to one of two constant temperature environments (15 or 22 °C). At maturity, the weight, SSC, and fruit development period (FDP) of tagged fruit were recorded. Fruit SSC was lower at the higher temperature (5.2% at 22 °C versus 6.5% at 15 °C) in both years. In 2007, SSC was not correlated with WPB, and in 2008, SSC was positively correlated with WPB at constant temperatures. In addition, the coefficient of determination (r 2) for a regression of SSC on mean temperature over the period 8 days before harvest was 0.73 for fruit harvested from fields between 2003 and 2009. These results indicate that rising temperature is a major factor responsible for the late-season decline of SSC in strawberry fruit in a subtropical production system.
Steven J. MacKenzie, Craig K. Chandler, Tomas Hasing and Vance M. Whitaker
R.J. McAvoy and H.W. Janes
Tomato seedlings (Lycopersicon esculentum Mill. cv. Laura) were grown in an environmental chamber. In two separate experiments, plant growth from emergence to anthesis was divided into three equivalent segments based on either the actual number of days or the stage of plant development. In both experiments, plants were exposed to a high PPF (300 μmol·s-1·m-2)2) treatment (H) for one segment and a lower PPF (150 μmol· s-1·m-2) treatment (L), for the other two segments, resulting in three light treatment combinations (i.e., HLL, LHL, and LLH). Total dry weight and dry weight per unit of leaf area increased significantly in response to high PPF during all three treatment periods. Final plant weights and plant heights differed significantly between treatments, resulting in distinct plant growth characteristics. Plants from the HLL treatment began to flower 1 day before the LHL treatment and 2 days before the LLH treatment. The HLL plants initiated fewer leaves before initiation of the floral axis than the LHL and LLH plants. The light environment following the initial segment of seedling development most influenced final truss position at anthesis.
Brian A. Mitchell, Mark E. Uchanski and Adriane Elliott
—Fort Collins. 8 Aug. 2018. < https://www.colorado . gov/pacific/sites/default/files/Old%20Town%20season%20ave%202015.pdf> Fanasca, S. Martino, A. Heuvelink, E. Stanghellini, C. 2007 Effect of electrical conductivity, fruit pruning, and truss position on quality