Arbuscular mycorrhizal inoculation and shading enhance crop performance and quality of greenhouse Begonia semperflorens

Mycorrhizal fungi are gaining interest in the floriculture sector due to the beneficial effects on a crop performance and ornamental quality. The aim of the current study was to assess the effect of inoculation with the arbuscular mycorrhizal (AM) fungi Rhizophagus irregularis on ornamental quality of Begonia × semperflorens-cultorum grown in two different protected cultivation systems: a shadehouse or glasshouse. The inoculated plants incurred a significant increase of plant height by 34.6%, lateral shoot length by 27.9%, number of lateral shoots by 41.2%, number of flowers per plant by 102.9%, flower diameter by 27.5%, and stems dry weight by 263.6%. High temperatures in the glasshouse negatively affected the AM root colonization. On the contrary, shading induced higher mycorrhizal colonization (48.6%) and increased plant height, number of lateral shoots, number of flowers per plant and flower diameter compared to the glasshouse environment. Taking all together, our results clearly demonstrated that mycorrhizal inoculation at transplanting and shading may be beneficial to floriculture growers wishing to produce high quality B. semperflorens-cultorum plants during the spring-summer season.