Influence of invections of mild isolates of different grapevine viruses on berry colour, texture, flavour and storage life of 'Crimson seedless' table grapes
‘Crimson Seedless’ grape is an economically important cultivar of table grapes with superior eating characteristics due to firmer berries, colour and good flavour. The aim of this research project was to investigate the influence of infection of mild isolates of grapevine leafroll associated viruses (GLRaV) 3, 5, 9 and grapevine virus A (GVA) on berry colour, texture, SSC, TA and SSC: acid ratio in ‘Crimson Seedless’ grapes during maturation, ripening and cold storage life and quality. The infection of GLRaV and GVA viruses in clone 3215 (LRV3 (E) + LRV3 (RT-PCR) + GVA + LRV9 + LRV5), clone 3236 + 3215 (LRV3 (E) + GVA + LRV9 + LRV5) reduced berry colour, SSC, SSC: acid ratio; improved berry springiness and gumminess without influencing acidity during maturation and ripening in comparison to virus free control. During cold storage, berries from viral infected clones 3236 + 3215 and 3215 showed improvement in berry colour and SSC and retained good quality until 140 days of storage but, there was no effect on acidity.Berry hardness, gumminess, springiness and cohesiveness were also higher in viral infected clone 3236 + 3215 and clone 3215 than virus free control during cold storage. In sensory evaluation, virus infected clones 3236 + 3215 and 3215 obtained higher scores for berry crispiness, flavour and overall acceptability during cold storage when compared to the virus free controls. In conclusion, the infection of mild isolates of GLRaV and GVA viruses reduced berry colour and SSC but, improved berry textural properties in clones 3236 + 3215 and 3215 of ‘Crimson Seedless’ grapes during maturation and ripening. The quality parameters such as berry colour, textural properties, SSC, TA and sensory scores also remained acceptable for these clones till 140 days cold storage at 0 ± 0.5oC
