الفهرس 
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Abstract
The current study was carried out through 2021 and 2022 seasons on peach trees (Prunus persica) cv. Swelling. Trees are grown in a private orchard at El-Shaarawy village, El-Behera Governorate, Egypt (latitude, 30̊70` N; longitude, 30̊27`E). And picked fruits were placed in plastic boxes (7kg capacity) and transferred immediately after harvesting to Horticulture Research Institute (HRI) located in Giza, Egypt in order to evaluate the effectiveness of pre-harvest appli-cations of CaNi, SA and OA as individual and combined treatments on retaining quality parameters along the storage duration at (0±1°C and 90-95% RH) and during shelf life period at (20±3°C and 60-65% RH) of peach fruits cv. Swelling. The obtained results could be summarized as following: V.1- Effect of pre-harvest applications of calcium nitrate, salicylic acid, ox-alic acid and their combinations on fruits physical characteristics during cold storage and shelf life V.1.1- Physiological weight loss percentage (PWL %) The advancement of cold storage duration from zero to 30 days resulted in significant losses in peach fruit weight Moreover, transferring fruits to the ambi-ent conditions after each storage interval led to additional increase in fruit weight loss. Pre-harvest spraying of ‘Swelling’ peach fruits with SA at 2mM, OA at 5mM and CaNi at 2% as singular and combined treatments resulted a significant reduc-tion in fruit weight loss as compared with controlled fruits during cold storage period as well as during shelf life after each storage interval. Moreover, the com-bined treatments were better than individual ones in reducing the weight loss percentage. CaNi at 2% combined with SA at 2mM was the best treatment at all in reducing weight loss. Additionally, among the singular treatments SA was 117 more effective than OA and calcium nitrate in controlling weight loss during the two seasons of study. V.1.2- Decay incidence (%) and decay index The elongation of cold storage period led to a significant increase in decay incidence and decay index. Moreover, shelf life for 3 days after each storage pe-riod resulted in further decay incidence and decay index. All pre-harvest treatments resulted in significant decrease in decay incidence and decay index as compared with un-treated fruits during cold storage period as well as during shelf life subsequent to each storage period. Moreover, the com-bined treatments were more effective than singular ones in reducing the increase in these parameters. Fruits treated with CaNi at 2% plus SA at 2mM recorded the lowest decay incidence and decay index. V.1.3-Visual appearance score The visual appearance score of peach fruits showed a declining pattern along the cold storage period as well as during ripening at ambient conditions after each storage period. Peach fruits obtained from trees sprayed with SA at 2mM, OA at 5mM and CaNi at 2% along with their combinations recorded a higher visual appearance score in comparison to control during cold storage period and during shelf life after each storage period. Specially, combined treatments were better than indi-vidual ones in maintaining the fruits visual appearance. Among the entire treat-ments CaNi at 2% plus SA at 2mM was the most favorable one in retarding the decrease in visual appearance score. V.1.4- Flesh firmness The peach fruit flesh firmness recorded a significant and gradual reduction with the advancement of cold storage period as well as during ripening at ambi-ent conditions after each storage period. 118 All pre-harvest treatments maintained higher firmness in comparison to con-trol during cold storage period and during shelf life following each storage period. Moreover, combined treatments maintained the fruit firmness better than indi-vidual treatments. CaNi at 2% combined with SA at 2mM was the best treatment in retarding the decrease in the fruit flesh firmness. V.2- Effect of pre-harvest applications of calcium nitrate, salicylic acid, ox-alic acid and their combinations on fruit chemical properties of ‘Swelling’ peach fruits V.2.1- Total soluble solids (TSS) With the advancement of cold storage period as well as shelf life subsequent to each storage period, the TSS of ‘Swelling’ peaches showed a significant in-creasing trend. With respect to pre-harvest applications of peach fruits with SA at 2mM SA, OA at 5mM OA and CaNi at 2% as well as their combinations, all treatments ex-ceeded the control in delaying the increase in TSS during cold storage period and after ripening subsequent to each storage interval. Moreover, the combined treatments were better than singular ones in delaying this increase in TSS. Fruits sprayed with CaNi at 2% combined with SA at 2mM recorded the lowest fruit contents of TSS in both seasons of study. Moreover, SA alone was more effective than OA alone and calcium nitrate alone in retarding the increase in TSS till the end of storage period and shelf life. V.2.2- Titratable acidity (TA) contents As the storage period increased, TA of ‘Swelling’ peach fruits significantly and gradually decreased to reach its minimum levels at the end of 30 days of cold storage as well as after 30 days of cold storage plus 3 days of shelf life. All treatments were better than the control in maintaining TA along cold stor-age period and during shelf life period. Furthermore, the combined treatments effectively maintained the TA level better than individual treatments. Among all 119 treatments, combination of CaNi at 2% with SA at 2mM recorded the highest contents of TA in both seasons of study. Moreover, SA alone was more effective than OA alone and calcium nitrate alone in maintaining fruit content of TA until the end of storage period and shelf life. V.2.3- TSS/Acid ratio TSS/TA ratio of ‘Swelling’ peach fruits gradually and significantly increased with increasing of cold storage period and along shelf life after each storage in-terval. Regarding pre-harvest applications, all treatments significantly delayed the in-crease in TSS/Acid ratio during cold storage period and after ripening subsequent to each storage interval. Additionally, the combined treatments were more effec-tive than individual ones in slowing this increase TSS/Acid ratio. Furthermore, CaNi at 2% combined with SA at 2mM treatment recorded the lowest TSS/Acid ratio. Moreover, SA alone was more effective than OA alone and calcium nitrate alone in retarding the increase in TSS/TA ratio up to the end of storage period and shelf life. V.2.4- Total sugars content (TS) Results revealed that the total sugars content gradually and significantly in-creased till 20 days of cold storage and followed by a slight increase in the 2021 season, whereas a slight decrease in 2022 season up to 30 days of cold storage. Moreover, transferring fruits from cold storage to the ambient conditions for 3 days led to additional increase in TS contents till 20 days of cold storage periods plus 3 days of shelf life followed by a decline up to 30 days of storage periods plus 3 days of shelf life. As for the effect of treatments, all treatments were better than the control in delaying the increase in TS content of ‘Swelling’ peach fruits Moreover, com-bined treatments significantly lowered the TS contents of ‘Swelling’ peach fruits as compared to individual ones. Pre-harvest application of ‘Swelling’ peach fruits with CaNi at 2% combined with SA at 2mM showed the significantly lowest TS contents during cold storage periods at (0±1°C and 90% RH) in 2021 and 2022 seasons. The significantly highest TS contents were obtained under the individual treatment of CaNi at 2% treatment which followed by OA at 5mM singular treatment during cold storage periods in both seasons. With respect to the effect of shelf life on TS contents of ‘Swelling’ peach fruits, the significantly lowest TS contents were recorded in fruits treated with CaNi at 2% combined with SA at 2mM followed by a combination between CaNi at 2% and OA at 5mM treatment during 30 days of cold storage plus 3 days of shelf life in both seasons. However, individual treatments showed the highest TS contents with no significant differ-ence between them during 3 days of shelf life subsequent to cold storage period. The control fruits followed the individual treatments in TS contents during 3 days of shelf life after each cold storage period in the two seasons. V.2.5- Ascorbic acid (AsA) content AsA content of ‘Swelling’ peach fruits gradually and significantly decreased with the advancement of cold storage periods as well as during shelf life after each storage interval in both seasons. Our investigations revealed that all pre-harvest treatments of ‘Swelling’ peaches significantly restricted the decline in AsA content relative to control during cold storage as well as during shelf life at ambient conditions. In addition, combined treatments were more effective in this aspect than individual treatments in the two seasons of the study. During cold storage and during shelf life subse-quent to each storage period, CaNi at 2% plus SA at 2mM treatment significantly maintained the highest fruit contents of AsA followed by CaNi at 2% combined with OA at 5mM treatment in the 1st and 2nd seasons. 121 V.2.6- Total anthocyanin content The total anthocyanin content of ‘Swelling’ peach fruits gradually and signifi-cantly increased till 20 days of cold storage period followed by slight increase after 30 days of cold storage in the 1st and 2nd seasons of study. Regarding the effect of treatments, all pre-harvest applications significantly delayed the increase in total anthocyanin content relative to untreated peach fruits during 30 days of cold storage and during 3 days of shelf life subsequent to each storage period in 2021 and 2022 seasons. Additionally, combined treatments were more effective in delaying the increase in total anthocyanin content of peach fruits. The maximum total anthocyanin content was observed in the peach fruits obtained from control trees during cold storage periods and during shelf life in the two seasons. In contrast to this, peach fruits sprayed with a combined treat-ment of CaNi at 2% with SA at 2mM showed the minimum total anthocyanin content in the 1st and 2nd seasons. IV.2.7- Total phenolic contents (TPC) TPC of ‘Swelling’ peach fruits showed a significant increasing pattern along 20 days of cold storage period as well as during 3 days of shelf life after 20 days of cold storage period subsequently decreased till the end of 30 days the cold storage and till the end of 3 days of shelf life after 30 days of cold storage in 2021 and 2022 seasons. Results also showed that, all pre-harvest applications of ‘Swelling’ peach fruits significantly increased TPC as compared to control during cold storage as well as after shelf life for 3 days at ambient conditions subsequent to each storage interval in both seasons. Additionally, combined treatments were more effective in this aspect as compared with singular ones. Peach fruits treated with CaNi at 2% plus SA at 2mM recorded the significantly highest TPC along 30 days of cold storage as well as during shelf life subsequent to each cold storage period in the 1st and 2nd seasons. 122 IV.2.8- Total antioxidant activity (TAA) As for TAA during cold storage periods, TAA of ‘Swelling’ peaches signifi-cantly increased up to the end of cold storage period in 2021 and 2022 seasons. However, during shelf life, a gradual and significant increase in the TAA oc-curred till 20 days of cold storage plus 3 days of shelf life followed by a reduc-tion after 30 days of cold storage plus 3 days of shelf life at ambient conditions in the two seasons. All pre-harvest applications of ‘Swelling’ peach fruits significantly maintained TAA as compared to control during cold storage as well as after shelf life for 3 days after each storage period in both seasons. Moreover, combined treatments were better than individual treatments in reserving TAA. The significantly max-imum TAA was observed in fruits treated with a combination between CaNi at 2% and SA at 2mM during 30 days of cold storage as well as during shelf life fol-lowing each cold storage period in the 1st and 2nd seasons.