The peach industry faces serious economic losses because of the short “green” life of the fruit at postharvest. In the present study, we investigated the effects of putrescine (PUT) application on the quality characteristics, pattern of ripening, storage behaviour and shelf life of peach fruit during low-temperature storage. The aqueous solution of PUT (0, 1, 2 and 3 mM) was applied to the peach trees at three distinctive stages of fruit growth and development. The fruits, harvested at the commercial stage of maturity, were stored at 1 ± 1 °C and 90 ± 2% relative humidity for 6 weeks. The data for fruit firmness, total soluble solids (SSC), titratable acidity (TA), ascorbic acid (AsA) content, rate of ethylene production, chilling injury (CI) index and colour perception were collected at harvest and then on a weekly basis throughout the storage period. The results showed that spray application of PUT significantly reduced the incidence of CI and reduced the rates of fruit softening, loss in fruit weight, SSC, TA, AsA content and fading of skin colour during storage, regardless of the doses of PUT applied, or the time of application. However, the positive effects on the quality characteristics of peach fruit, including CI, were more pronounced with the higher doses of PUT, specifically when applied at 2 mM. In conclusion, CI in peach fruit may be substantially alleviated by the spray application of 1–3 mM PUT during fruit growth without compromising the quality of the fruit for up to 6 weeks in low-temperature storage.

Owing to the high degree of perishability of the fruit, the peach industry faces serious challenges tackling physiological disorders, microbial/chemical decay, and the suboptimal quality of the fruit during and following cold storage. The present study was aimed to investigate the effects of spray applications of calcium chloride (CaCl₂) at various physiological stages of fruit growth and development, on ripening, flesh softening, chilling injury (CI) and nutritional quality of peach fruit cv “Flordaking” during low-temperature storage. The aqueous solutions of CaCl₂ [0, 1, 2, and 3% (w/v)] were sprayed on peach trees during cell division, pit hardening and cell expansion stages in 2011 and 2012. At commercial harvest, the fruit were hand-picked and were subjected to cold storage at 1 ± 1°C (RH: 90 ± 5%) for 6 weeks. The data on CI index and other quality characteristics of the fruit were recorded at harvest and then weekly for up to 6 weeks. The results showed that the pre-harvest spray application of CaCl₂ substantially reduced the incidence of chilling injury (CI) and delayed climacteric ripening seemingly by lowering the rates of ethylene production and fruit softening during storage as compared to control, regardless the doses of CaCl₂ and its application time, however higher doses of calcium chloride proved to be toxic causing blemishes on the surface of “Flordaking” peaches. In conclusion, pre-harvest spray application of CaCl₂ @ 1% may be a successful production management tool to maintain the quality and to extend storability of peach fruit during cold storage.

Peaches are well-liked amongst the stone fruits in Pakistan. The peach industry faces significant losses, from harvesting to marketing. The objective of this study was to investigate the effectiveness of foliar sprays of salicylic acid (SA) on the fruit quality of peaches (cv. ‘Flordaking’) at the harvest and postharvest life or stages. Different concentrations of SA (control, 1, 2 and 3 mM) were sprayed on the plants at three growth stages of fruit, i.e., the cell division, cell enlargement and pit-hardening stages. In general, all the SA treatments improved the fruit quality at harvest and maintained higher levels of flesh firmness, titratable acidity and ascorbic acid during storage. However, fruit weight loss, soluble solid contents, membrane leakage, chilling injury, color development, disease and decay incidence and the climacteric peak of ethylene were lowered by SA treatment after six weeks of low-temperature storage. SA at a 3-mM concentration was proven to be the most effective in maintaining the quality for a longer period of time during low-temperature storage. Based on the results, it can be concluded that the application of SA at fruit development stages can improve the harvest quality and storability of ‘Flordaking’ peaches.

‘ Kinnow’ mandarin (Citrus nobilis L.× Citrus deliciosa T.) is an important marketable fruit of the world. It is mainstay of citrus industry in Pakistan, having great export potential. But out of total production of the country only 10% of the produce meets the international quality standard for export. Pre-harvest fruit drop and poor fruit quality could be associated with various issues including the plant nutrition. Most of the farmers do not pay attention to the supply of micro nutrients which are already deficient in the soil. Furthermore, their mobility within plants is also a question. Zinc (Zn) is amongst those micronutrients which affect the quality and postharvest life of the fruit and its deficiency in Pakistani soils is already reported by many researchers. Therefore, this study was carried out to evaluate the influence of pre-harvest applications of zinc sulfate (ZnSO4; 0, 0.4%, 0.6% or 0.8%) on pre-harvest fruit drop, yield and fruit quality of ‘Kinnow’ mandarin at harvest. The treatments were applied during the month of October i.e. 4 months prior to harvest. The applied Zn sprays had significant effect on yield and quality of the “Kinnow” fruit. Amongst different foliar applications of ZnSO4applied four months before harvest, 0.6% ZnSO4 significantly reduced pre-harvest fruit drop (10.08%) as compared to untreated control trees (46.45%). Similarly, the maximum number of fruits harvested per tree (627), fruit weight (192.9 g), juice percentage (42.2%), total soluble solids (9.5 °Brix), ascorbic acid content (35.5 mg 100 g-1) and sugar contents (17.4) were also found significantly higher with 0.6% ZnSO4 treatment as compared to rest of treatments and control. Foliar application of 0.6% ZnSO4 also significantly improved total antioxidants (TAO) and total phenolic contents (TPC) in fruit. In conclusion, foliar spray of ZnSO4 (0.6%) four months prior to harvest reduced pre-harvest fruit drop, increase yield with improved quality of ‘Kinnow’ mandarin fruit.

Micronutrient (iron, zinc and boron) deficiencies are a basic and prominent factor affecting grape quality and yield in the Pothwar region. To overcome these deficiencies, different levels of micronutrients were applied foliarly on grapevines at five different berry developmental stages during two consecutive growing seasons (2018 and 2019). The data suggested that foliar treatment of micronutrients significantly increased the yield, number of bunches per vine, bunch weight, yield per vines, bunch length, berry number per cluster, berry diameter, berry weight and cluster compactness. The biochemical quality attributes of berries, including sugars (reducing, non-reducing as well as total sugars), ascorbic acid content, pH and TSS values, were at their highest levels in grapevines supplemented with Fe, Zn and B treatment at 200 ppm, respectively, i.e., the highest concentrations used. Biochemical leaf values, including chlorophyll a and b and leaf micronutrient content (Fe, Zn and B), were also highest in grapevines that were sprayed with Fe, Zn and B at 200 ppm. Overall, the results revealed that the performance of grapevine cv. ‘Flame Seedless’ growing in agroclimatic conditions of the Pothwar region was improved as a result of the foliar application of Fe, Zn and B at 200 ppm. The results also suggested that a further increase in the concentration of each nutrient might be helpful to obtain berries of improved quantity and quality.

Transplanting time and genotype contribute to improving crop yield and quality of eggplant (Solanum melongena L.). A field experiment was conducted to investigate the impact of foliar applied of triacontanol (TRIA) and eggplant genotypes 25919, Nirala, 28389 and Pak-10927,transplanted on 1 March,15 March, and 1 April on exposure to high air temperature conditions. The experiment was performed according to Randomized Complete Block Design and the data was analyzed by using Tuckey,s test . The TRIA was applied at 10µM at flowering stage; distilled water was used as the control. Rate of photosynthesis and transpiration, stomatal conductance, water use efficiency, and effects on antioxidative enzymes (superoxide dismutase, catalase and peroxidase) were evaluated. The 10µM TRIA increased photosynthesis rate and water use efficiency and yield was improved in all genotypes transplanted at the different dates. Foliar application of 10µM TRIA increased antioxidative enzyme activities (SOD, POD & CAT) and improved physiological as well as biochemical attributes of eggplant genotypes exposed to high heat conditions. Highest activity of dismutase enzyme 5.41mg/1g FW was recorded in Nirala genotype in second transplantation. Whereas, lowest was noted in PAK-10927 (2.30mg/g FW). Maximum fruit yield was found in accession 25919 (1.725kg per plant) at 1^st transplantation with Triacontanol, whereas accession PAK-10927 gave the lowest yield (0.285 kg per plant) at control treatment on 3^rd transplantation. Genotype, transplanting date and application of TRIA improved growth, yield and quality attributes under of heat stress in eggplant.