GRAY MOLD (BOTRYTIS CINEREA) INDUCED BERRY CRACKING IN 'FUJIMINORI' TABLE GRAPES (VITIS SP.)
Tetraploid grape cultivars including Fujiminori are cultivated for higher quality and marketability in table grape production using a protected rain-shelter cultivation system in Korea. Gray mold (Botrytis cinerea) is one of the serious diseases affecting tetraploid grape cultivation. To research the berry cracking symptoms caused by B. cinerea infection, morphological and cellular characteristics were observed using cracking susceptible Fujiminori grapevines. The intact berry rate indicative of marketability was decreased to 62.7% after the inoculation compared to 89.3% in the control vines. Cluster weight and numbers of berries per cluster on inoculated vines was also significantly decreased; 535.6 g and 28.2 compared with 842.2 g and 40.2 in non-inoculated controls. The decrease in berry firmness from 1.31 to 1.08 kg∙5 mm-1 ⌀ with gray mold inoculated vines induced a three-fold higher berry cracking rate under critical turgor pressure from 18.0 to 52.0%. The cell wall content per 10 g of pericarp, which can be an indicator of the strength of cell wall structure, was reduced 45.9% from 453.7 to 245.3 mg in gray mold infected Fujiminori vines. The increase in polygalacturonase activity from 0.143 to 0.204 units∙ml-1 after the infection of B. cinerea could also accelerate cell wall degradation and berry cracking. Though there are no visible disease symptoms on the surface of berry in the early berry growth stage before veraison, invaded hyphae of B. cinerea infection were already promoting cell breakdown between the sub-epidermal and the epidermal layer by secreting cell wall degrading enzymes. Therefore, the susceptibility and infection of B. cinerea before veraison can be an important trigger for berry cracking.
Daeil Kim, , Sung-Il Oh , and In-Chang Son, (2014). GRAY MOLD (BOTRYTIS CINEREA) INDUCED BERRY CRACKING IN 'FUJIMINORI' TABLE GRAPES (VITIS SP.). Acta Hortic. 1046, 133-138
cell wall, degradation, gray mold, infection, splitting