The influence of rootstock on postharvest chilling injury susceptibility

Citrus rootstocks directly influence tree vigor and size, tolerance to numerous biotic and abiotic threats, yield, and various fruit quality factors.
However, the impact on a complex postharvest disorder, which is a distillation of environmental conditions, production practices, and genetic origin, is not well documented.
Chilling injury severity (CIS) of fruit sampled from ‘Star Ruby’ grapefruit (Citrus paradisi Macf.) grafted on 24 rootstocks and ‘Delta’ and ‘Midknight’ Valencia (C. sinensis (L.) Osbeck) on seven rootstocks was determined to ascertain the role of rootstocks on chilling injury (CI). Tree vigor and canopy volume were the most notable effects of rootstock, although these differences had limited effects on fruit quality.
In ‘Delta’ Valencia, the rootstock effect on CI was a direct effect rather than an indirect one mediated through differences in fruit quality characteristics.
The inconsistencies in fruit susceptibility from trees on X639 (‘Cleopatra’ mandarin × trifoliate), with a high CI incidence in ‘Midknight’ and a low incidence in ‘Delta’ Valencia, demonstrated the interactive effects between rootstock and scion.
Rootstocks do not impart the same postharvest chilling tolerances across different scion cultivars.
The mechanism by which rootstocks influence fruit quality and, to an even greater degree, CI, still needs to be elucidated; however, the direct or indirect impact of the rootstock on rind condition and susceptibility is clear.

XV International Citrus Congress

P.J.R. Cronje, J.J. North

cold storage, internal and external quality

https://doi.org/10.17660/ActaHortic.2026.1448.85