Temperature affects dry matter production and net carbon exchange rate of lower-ploidy Fragaria species and species hybrids

Abstract

Wild species can contribute to a breeding program through their wide adaptability to a range of habitats. In interspecific crosses it is not known how these species may interact in the hybrids. The dry matter production and net carbon exchange rates (NCER) of four lower-ploidy Fragaria species, four species hybrids (synthetic octoploids, SOs) and two cultivars (Allstar and Jewel) were compared under three day/night temperature regimes, low (15°C/10°C), medium (23°C/18°C) and high (30°C/25°C) in growth cabinets. Light intensity was maintained at 425 µmol m-2 s-1 and day length at 14 h. The wild Fragaria species had the highest NCERs across all temperature regimes. High temperatures had a depressing effect on plant dry weight for most genotypes. However, F. nubicola and SO 8245 produced 15 and 33%, respectively, higher plant dry weight at the high temperature compared with the low temperature treatment. Net carbon exchange rates for most species and synthetic octoploids were not significantly affected by high temperature. However, SO 8212 did not survive the high temperature treatment. The lower ploidy Fragaria species can be used to create synthetic octoploids that can maintain net carbon exchange rates and produce plant dry weights that are comparable with those of Fragaria cultivars. The ecological background of the species did not have a negative impact on the plant dry weight and NCER of the synthetic octoploids. Some of the SOs may be sources for improvement of Fragaria cultivars for dry matter production at higher temperatures.