Temperature and photoperiod effects on growth and development of day-neutral, junebearing and everbearing strawberries

Abstract

Responses of day-neutral (DN) strawberries (Fragaria X ananassa Duch.) to photoperiod and temperature under controlled environment conditions were studied and compared to those of Junebearers (JB) and everbearers (EB). At a constant 21°C, DN cultivars flowered under 9 hour days (SD), night interrupted SD (NI) and 16 hour days (LD). Runner production occurred under NI and LD but not SD. Net photosynthesis (Pn) expressed on a leaf area basis, tended to be higher for DN than JB or EB. Pn on a whole plant basis, was greater under NI than SD due to increased leaf area under NI. Pn under LD was not considered. Under fluctuating temperatures (18°/14°, 22°/18°, 26°/22° or 30°/26° C day/night combinations), responses to SD and NI varied. At 18/14, DN cultivars flowered under either NI or SD. At 22/18 and 26/22, flowering was greater under NI than SD. At 30/26, flowering did not occur. At 18/14, 22/18, or 30/26, runner production was unaffected by photoperiod and occurred under NI and SD. At 26/22, runner production was enhanced by NI compared to SD. Data for the Junebearers and everbearers is also presented and discussed.