Influence of high tunnel and field conditions on strawberry growth and development

Abstract

Plant growth, yield, and fruit quality of two strawberries (Fragaria xananassa Buch.) - 'Chandler' and 'Sweet Charlie' - grown under high tunnels (HTs) were compared with that of field plants during 2002-03 and 2003-04 growing seasons. Plug plants were planted in mid-October 2002 and mid-September 2003 on raised beds covered with black polyethylene mulch. Microclimate of the HTs protected strawberry crowns from winter damage and advanced fruit production 5 weeks earlier than that of plants grown under field conditions. From December to February, average minimum and maximum crown temperatures under the HTs were 5 and 12°C warmer than those of the field crowns, respectively. The earliest HT fruit were harvested on 7 Apr. 2003 and 11 Mar. 2004. Yield and fruit quality under the HTs were superior to that of field-grown plants. HT plants, especially 'Sweet Charlie', bloomed earlier than did field plants, but 'Chandler' produced higher yield than 'Sweet Charlie' late in the season. Larger fruit with higher soluble solids concentration (SSC) were produced inside the HTs than outside. HT 'Sweet Charlie' fruit were sweeter than 'Chandler' fruit, but 'Chandler' produced larger fruit. Larger leaf area, greater number of leaves and shoot biomass, more branch-crowns, and fewer runners were developed under HTs than field conditions. Total leaf area, leaf production, total shoot biomass, and number of branch-crowns of HT 'Chandler' were greater than HT 'Sweet Charlie'. Results of this study indicate that strawberry plants under HTs were not only precocious, but also produced higher yields and superior quality to that of field plants. HT conditions suppressed runner growth, but enhanced branch-crown development.