الفهرس 
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Abstract
This study was conducted during two successive seasons of 2020 and 2021 on Manfalouty pomegranate cultivar grown at the Experimental Orchard of the Faculty of Agriculture, Assiut University. Twenty-eight uniform trees were selected. The experiment was set as a complete randomized blocked design (CRBD) including seven treatments and four replicates per each treatment. Combined analysis over seasons was used. The treatments were carried out as following foliar application with calcium chloride (2 and 4% CaCl2) and potassium nitrate (250 and 500 ppm KNO3) alone or combined with flower thinning (CaCl2 4% + KNO3 500 ppm + Flower thinning) and control. The spraying treatments took place three times, at the beginning of flowering (during April), after fruit set completion (first July) and before harvesting (first September), during the two seasons of study. Hand flower thinning was down to all the flowers that appeared during the last week of May till the end of flowering period as recommended by El-Sese (1988a,b) and (El-Sese and Mohamed 2005). The following parameters were recorded:
1- Yield components
At harvest, the fruits of all the treated trees were picked at mid-October in the two seasons. Fruits were counted and weighted to estimate the total yield weight (kg/tree) and calculate the average fruit weight (g). As well the cracked fruits were sorted, counted, weighted and the percentage of fruit cracking was calculated relative to the total number of fruits.
2- Physical properties
Samples of four fruits per tree replications were collected randomly for determining the physical properties. Fruit length (cm) and fruit diameter (cm) were estimated and then the ratio between them was calculated. In order to determine arils weight (g), fruits were manually peeled and the weight of total arils were measured. Also, the juice weight of 100 g arils (g) and the juice volume of 100 g arils (cm3) were calculated.
3- Chemical properties
3-1- Fruit sensory attributes
Total acidity was determined using titration by NaOH at 0.1 N and phenolphthalene as an indicator then, expressed as citric acid, according to following equation (A.O.A.C., 1995)
Total soluble solids (TSS %) was measured using the hand refractometer and then, TSS/Acid ratio was calculated. The percentage of reducing sugars in juice was determined, according to A.O.A.C. (1995).
3-2- Total anthocyanin content (TAC) of juice
The extracts were prepared and then absorbance of the solution was measured at a wave length of 530 nm, using spectrophotometer.
The obtained results can be summarized as following:
1- Yield components and fruit cracking %
1-1- The yield weight (kg/tree)
The results displayed the extent to which all the treatments were positive in their effect on the total yield/tree compared to the control during the two seasons of the study. In addition, the best influencing treatment on the yield was KNO3 at 500 ppm followed by the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4% which gave an average yield 69.5, 66.5 and 61.4 (kg/tree) with an increment of 43.0, 36.8 and 26.3% over the control treatment, respectively, while the lowest impact influence was the control treatment.
1-2- Fruit weight (g)
The results showed that there were no significant differences between the two CaCl2 concentrations and KNO3 at 250 ppm, however, the concentration of CaCl2 at 4% was more effective than the two other treatments in its effect on fruit weight. Moreover, the best treatment in its effect on the average fruit weight was KNO3 at 500 ppm which gave the highest enormousness of average fruit weight 475.5 g with an increment of 26.3%, followed by the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4% which gave an average fruit weight of 450.6 and 442.4 g with an increment of 19.6 and 17.5% over the control, respectively, whereas, the control treatment gave the lowest value as an average of the two seasons of study.
1-3- Fruit cracking %
The results exposed all treatments caused a reduction in the percentage of fruit cracking compared to the control treatment, and these differences were significant as an average of two successive seasons. Likewise, the KNO3 at 500 ppm treatment is considered the best in obtaining the least fruit cracking compared to other spraying treatments and the control. It gave 2.8% of fruit cracking as an average of two seasons with a decrement of 70.5% than the control, followed by each of the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and KNO3 at 250 ppm, while, the control treatment gave the highest values (9.5%) as an average of the two successive seasons.
2- Fruit physical properties
2-1- Fruit length (cm)
There were no significant differences between the two concentrations of calcium chloride (CaCl2), potassium nitrate (KNO3) and the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) in its effect on fruit length. Furthermore, the data showed that the KNO3 at 500 ppm and CaCl2 at 4% treatments gave the highest values of the fruit length with no significant differences between them. They gave 8.0 and 7.8 cm with an increment of 8.1 and 5.4% over the control treatment, respectively, followed by each of the CaCl2 at 2% and KNO3 at 250 ppm which gave the same value 7.7 cm with an increment of 4.1%. Whereas the control treatment recorded the lowest value of average fruit length 7.4 cm as an average of the two season of study.
2-2- Fruit diameter (cm)
The results showed that there were no significant differences between the two concentrations of CaCl2 in the two seasons of study, also between the flower thinning and the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) in its effect on fruit diameter. Furthermore, the best treatment in its effect on the fruit diameter was KNO3 at 500 ppm treatment, which gave the highest value of fruit diameter 8.7 cm with an increment of 7.4% over the control, followed by CaCl2 at 2% and CaCl2 at 4% which gave the same value of fruit diameter 8.4 cm with an increment of 3.7% over the control treatment as an average of the two successive seasons. Whereas, the control treatment gave the lowest value.
2-3- L/D ratio
There were no significant differences between all treatment and the control in its effect on the L/D ratio, whereas, each of CaCl2 at 4%, KNO3 at 250 ppm and the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) gave the best values.
2-4- Aril weight (g)
The results showed that there were no differences significant between the flower thinning, KNO3 at 250 ppm and CaCl2 at 2% treatments in its effect on the aril weight. In addition, the KNO3 at 500 ppm treatment gave the highest significance of aril weight (g) followed by the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4% treatments. They gave 291.3, 274.9 and 270.1g with an increment of 25.5, 18.4 and 16.4% over the control, respectively. Whereas the control treatment recorded the lowest value which gave an average aril weight 232.1g as an average of the two seasons of study.
2-5- Juice weight/100g aril (g)
The data presented that there were no significant differences between the two concentration of CaCl2 and the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) in its effects on average juice weight/100g aril, while the flower thinning treatment gave the lower effect. Furthermore, the best treatment in this respect was KNO3 500 ppm followed by each of the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4%. They recorded 76.2, 74.4 and 73.5 g with an increment of 17.1, 14.3 and 12.9%, respective, whereas, the control treatment gave the lowest value.
2-6- Juice volume/100g aril (cm3)
It was clear significance of each of KNO3 at 500 ppm and the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4% treatments in its effects on juice volume/100g aril compared to the control. They recorded values of 55.6 and 54.0 and 52.8 cm3 with an increment of 13.4, 10.2 and 7.8%, respectively, followed by CaCl2 at 2% treatment which recorded the value of 50.3 cm3 with an increment of 2.7% over the control, while the control treatment recorded the lowest value (49.0 cm3) as an average of the two successive seasons.
3- Fruit chemical constituents
3-1- Total soluble solids percentage (TSS%)
There were no significant differences between CaCl2 at 4% and the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) in its effects on TSS%, which, gave a value of 16.5%. Similarity, there were no significant differences between CaCl2 at 2% and KNO3 at 250 ppm treatments in its effects on TSS%, which, gave a value of 16.0 and 15.7%, respectively as an average of the two seasons of study. Moreover, the best treatment in its respecting the TSS% was KNO3 at 500 ppm followed by each of the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4%. The percentages of these later treatments were 16.9, 16.5 and 16.5% as an average of the two seasons of study, respectively, while the flower thinning and the control treatments gave the lowest value of the TSS%.
3-2-Total acidity percentage
The presented data suggested that all the treatments provided a significant lower acidity percentage compared to the control as an average of the two studied seasons. Furthermore, KNO3 at 500 ppm treatment gave the lowest acidity percentage (0.93%) compared to the other treatments, followed by the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) which gave a total acidity of 1.00%, while the control gave the highest value of total acidity 1.37% as an average of the two seasons of the study.
3-3- TSS/acid ratio
There were no significant differences between the two concentration of CaCl2, as well as between KNO3 at 250 ppm and flower thinning treatments in its effects on TSS/acid ratio as an average of the two successive seasons. In addition, the highest ratio was taken from KNO3 at 500 ppm treatment followed by the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning). They gave a value ratio of 18.4 and 16.9, respectively, while the control treatment gave the lowest ratio 12.3 as an average of the two studied seasons.
3-4- Reducing Sugars %
The results showed that all treatments had a positive effect and caused a significant increase in reducing sugars % compared to the control treatment during the two seasons of study. Likewise, the best influencing treatment on the reducing sugars % was KNO3 at 500 ppm which gave an average of 14.51% with an increment of 49.1% over the control followed by the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4% treatments which gave an average of 12.44 and 11.63% with an increment of 27.9 and 19.5% over the control, respectively, with no significant differences between them, whereas the lowest value was the control treatment which gave 9.73% as an average of both seasons of the study.
3-5-Total anthocyanin (mg/100g fruit)
All treatments showed superiority in their effect on the total anthocyanin content compared to the control treatment during the two seasons of study. Also, the results represented that there were no significant differences between the most of the treatments in their effects on the total anthocyanin content, while the flower thinning treatment gave the lower effect. Likewise, the KNO3 at 500 ppm gave the highest value of total anthocyanin content. It gave a value of 14.51 mg with an increment of 112.8% followed by the combined treatment (CaCl2 4% + KNO3 500 ppm + Flower Thinning) and CaCl2 at 4% treatment, which gave an average of 11.50 and 11. 29 mg with an increment of 68.2 and 65.5% over the control, respectively, whereas, the control treatment gave the lowest values.
CONCLUSION
On the light at previous results under the environmental condition of Assiut Governorate, it could be concluded that spraying 500 ppm KON3 or 4% CaCl2 alone or combined with flower thinning (during the last week of May till the end of flowering) are considered the best treatments in its effects on the yield components, fruit quality, anthocyanin content and decreasing the fruit cracking.