VEGETATIVE GROWTH ATTRIBUTES OF NORTH AMERICAN CULTIVARS WITH DIFFERING TEMPERATURE REGIMES.
Runner plants from 23 strawberry cultivars and selections (genotypes) were grown in controlled environment chambers to test for differences in vegetative growth traits with simulated fall/winter temperatures. Genotypes were included from germplasm adapted to four geographic origins: California, northwestern US, northeastern US, and mid-atlantic or southeastern US. The California genotypes were further divided into June bearing and day-neutral categories. To normalize for potential regional differences in vernalization requirement, runners received at least 1,000 hours below 7.2°C before the experiment began. Growth chamber treatments were 11, 14, and 17°C day temperatures, with a common night temperature of 11 C. Short days(11 hours) with relatively high irradiation (650–700 of μmol/m2/s PAR) were used to normalize flowering responses and to ensure that available light was not limiting. Statistically significant temperature and genotypic effects were detected for all growth traits, but no significant differences were detected among groups of genotypes from different geographical regions. Further, no significant temperature x genotype interaction or temperature × region interactions effects were detected. These results suggest that differences in regional adaptation of strawberry cultivars is a consequence of complex interactions, rather than a simple response to growing temperature, and that vigor in fully-vernalized strawberry plants is expressed uniformly among genotypes at low to moderate temperatures.
Rariden, John M. and Shaw, D. V. (1993). VEGETATIVE GROWTH ATTRIBUTES OF NORTH AMERICAN CULTIVARS WITH DIFFERING TEMPERATURE REGIMES.. Acta Hortic. 348, 109-116