Effects of CyMV–infected on Growth, Yield and Quality of Dendrobium Sonia ‘Earsakul’ under Difference Greenhouse

Abstract

Thailand is the world’s largest producer and exporter of Dendrobium orchid cut flowers. The most popular cultivated variety is Dendrobium Sonia ‘Earsakul’. However, an outbreak of disease caused by Cymbidium mosaic virus (CyMV) has increased during the long cultivation for 10 years and orchids were also repeatedly propagated by pseudobulb cutting. Therefore, this research aims to compare the growth, yield, flower quality, leaf pigment content and photosynthetic parameters in new pseudobulb of 1.5 year–old free–virus and CyMV-infected Dendrobium Sonia ‘Earsakul’ after transplanting from tissue culture under net shading greenhouse and plastic greenhouse at Thai Orchids company in Ratchaburi, Thailand. The experimental design was a 2×2 factorial in CRD. The results demonstrated that the CyMV virus infection reduced pseudobulb height, pseudobulb diameter and leaf number, but the leaf greenness was increased. Nevertheless, the chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, CO2 exchange rate, stomatal conductance, transpiration rate and water use efficiency in the virus-infected plant were not significantly different with the free–virus plants in both greenhouses. For the flower quality and quantity, the results found that the inflorescence number of the virus-infected plant was similar to the free-virus plants under two types of greenhouses. However, the inflorescence number in net shading greenhouse was higher than in plastic greenhouse. Virus infection plants had the longer vase life with 18 and 20 days, while free–virus plants had only 12 days.