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Cold quarantine treatment (1°C for 21 days) induces chilling injury (CI) in sweet orange fruit. We investigated the effects of different treatments such as hot water dip (HWD, 50 °C) alone or combined with thiabendazole (TBZ) five-minute, different concentrations of salicylic acid (SA), methyl jasmonate (MJ) one-minute dip and fumigation of nitric oxide (NO) two-hour and ethylene (ET) (six-hour) on CI and fruit quality following 21 days cold quarantine treatment and 10-day at ambient temperature in 'Lane Late' and 'Midknight Valencia' fruit. The experiment was laid out by following completely randomised design included three replications. HWD alone or combined with TBZ, or MJ significantly reduced CI in both cultivars. NO (5 μL L-1) fumigation significantly reduced weight loss in 'Lane Late' only as compared to all other treatments except SA (1, and 3 mM). SCC/TA ratio was significantly reduced with ethylene, HW alone or combined with TBZ or MJ (0.25 mM) as compared to all other treatments in 'Midknight Valencia', but not in 'Lane Late'. The NO (10 μL L-1) fumigation resulted in the significantly highest level of vitamin C only in 'Midknight Valencia'. SA (3 mM) dip treatment resulted in the significantly highest levels of total antioxidants as compared to all other treatments in 'Lane Late' but not in 'Midknight Valencia'. In conclusion, HWD alone or in combination with TBZ (20 mg L-1) or MJ (0.50 mM) effectively reduced CI caused after cold quarantine treatment without adversely affecting fruit quality.

Poor rind colour in cv. M7 Navel (Citrus sinensis L. Osbeck) at harvest time severely affects the profits of the growers in Western Australia. The effects of the preharvest spray application of different concentrations (0, 1.25, 2.5, 5.0 and 7.5 mM) of methyl jasmonate (MJ) on the rind colour development and fruit quality of M7 Navel were investigated at 6 or 3 weeks before anticipated harvest (WBAH) during 2015 and 2016. The preharvest spray application of MJ (5.0 or 7.5 mM) resulted in enhanced rind colour, reduced hue angle (ho) angle (55.7, 54.3) as well as increased citrus colour index (CCI) (11.0, 12.0) and total carotenoid levels (35.3, 58.3 mg kg-1) of flavedo, respectively in M7 Navel, during 2015 and 2016. During 2015, comparatively higher levels of total carotenoid (40.4 mg kg-1) were recorded when MJ was applied at 3 WBAH as a single spray. However, the time of MJ application did not influence hue angle (h°) and CCI. In 2015, all the preharvest MJ treatments except (1.25 mM) exhibited reduced fruit firmness. Furthermore, soluble solids concentration (SSC) in the fruit juice was reduced after MJ treatment. All the MJ treatments showed reduced levels of total sugars and organic acids in the juice, during 2015. In conclusion, MJ (5.0 or 7.5 mM) reduced h° but increased the total carotenoids levels and CCI in the flavedo of M7 Navel orange, when applied as a preharvest spray at 3 WBAH