PGPR Improves Yield of Strawberry Species under Less-Fertilized Conditions

Abstract

Plant growth promoting rhizobacteria (PGPR) is applied as biofertilizer to expect better production potential on commercial crops while keeping sustainability, but their function is dependent on the combination of PGPR and target crops. It has been reported that the application of PGPR in the soil resulted in the increment of strawberry yield, but other reports argue that PGPR has no effect on the yield potential. In addition, it is not clear whether the application timing of PGPR affects in a forcing cultivation system which usually requires transplanting. In this study, responses of diploid wild strawberry (Fragaria vesca) and garden strawberry (F.×ananassa Duch.) varieties to PGPR application were examined. Application of PGPR, Bacillus cereus KI-2, during the flower induction increased the total yield and number of fruits in F. vesca ‘Hawaii-4’, and in garden strawberry ‘Hoko-wase’. The application resulted in earlier flowering in ‘Hoko-wase’ while no difference was observed in ‘Tochi-otome’. Sucrose content was also altered in cultivar dependent manner so that it was increased in ‘Hawaii-4’, while it was decreased in ‘Tochi-otome’. These results indicate that PGPR has a potential to improve the yield factors while keeping the quality of the fruits, but the effect is cultivar dependent.