Plant Productions

Evaluation of the Effects of Calcium Nitrate and Potassium Phosphite on the Storage Life and Some Quality Traits of Thomson Navel Orange

Amirali Mohammadi; Mehrdad Shahabian; Mahmoud Reza Ramezanpour; Shokrollah Hajivand

Volume 45, Issue 2 , September 2022, , Pages 181-192

https://doi.org/10.22055/ppd.2021.35965.1959

Abstract

IntroductionOranges belong to the Citrus (family Rutaceae) and are an important source of antioxidants, including phenolic compounds and vitamin C. These compounds have a protective ... Read More IntroductionOranges belong to the Citrus (family Rutaceae) and are an important source of antioxidants, including phenolic compounds and vitamin C. These compounds have a protective effect against various diseases such as cancer and cardiovascular. Since there is a possibility of decay and rot of Citrus in all stages of harvest and post-harvest, the use of mineral elements may have an important effect on increasing the quality of the fruit and its shelf life. This effect varies depending on the species and cultivar of Citrus. Mineral elements, especially potassium and calcium, affect fruit growth and Citrus fruit quality. Materials and MethodsTo investigate the effect of spraying, a research was conducted in Qaemshahr city in 2019, which in this study, manual foliar application of calcium nitrate (0, 2 and 4 g / l) and potassium phosphite (0, 1.5 and 3 g / l) was done in the late October in three stages with a week interval. Then, one week after the last treatment, the harvesting operation was performed with garden shears. After washing, the fruits were kept in normal temperature for 3 months. Various parameters such as morphology (percentage of weight loss, firmness, percentage of decay, etc.), biochemical (total soluble solids (TSS), titratable acidity (TA) and acidity of fruit juice (pH)), antioxidant (percentage of inhibition and vitamin C), enzyme (ascorbate peroxidase and superoxide dismutase) and marketability traits were evaluated. Results and DiscussionThe results showed that the application of higher concentrations of calcium nitrate and potassium phosphite improved the measured traits at harvest day. The use of these materials has also increased the shelf life and quality of the fruit during storage. Fruits treated with calcium nitrate and potassium phosphite had more antioxidant properties on the day of harvest. The highest amount of vitamin C and inhibition percentage were observed in the treatment of 4 g / l calcium nitrate and 3 g / l potassium phosphite at harvest day. Treated fruits were more firm and less rotten during storage than control ones. Also, the treated fruits had more soluble solids and titratable acidity. Also, during storage, the quality of the fruit and its marketability decreased, but fruits treated with calcium nitrate and potassium phosphite received higher scores from the evaluators. The use of calcium increases the strength of the membrane and reduces the activity of enzymes that relax the cell wall, which therefore increases the firmness of the fruit and reduces the weight loss and rot of fruits during storage. The use of potassium phosphite has also been effective in reducing caries. Calcium along with potassium play a role in photosynthesis and cause the accumulation of sugars. Vitamin C is associated with a decrease during storage, due to the use of ascorbic acid as an ascorbate peroxidase cofactor. Finally, it seems that the marketability of the fruit has increased due to the increase of quality traits such as sugars, due to the use of calcium nitrate and potassium phosphite. ConclusionThe storage of Thomson Novel oranges was affected by the treatments used, and the highest firmness, weight and quality characteristics of the fruit were obtained in the highest amount of calcium nitrate and potassium phosphite. Also, the rate of caries has decreased significantly with the use of these treatments.

Predicting the Final Fruit Size of Kiwifruit cv. 'Hayward' Using Mathematical Equations

Ebrahim Abedi Gheshlaghi

Volume 44, Issue 3 , December 2021, , Pages 433-446

https://doi.org/10.22055/ppd.2020.30831.1818

Abstract

AbstractIntroductionFruit size is an important attribute of all fruit crops and harvest fruit weight has a major influence on market acceptance and returns for many fruit crops like ... Read More AbstractIntroductionFruit size is an important attribute of all fruit crops and harvest fruit weight has a major influence on market acceptance and returns for many fruit crops like kiwifruit (Actinidia deliciosa 'Hayward'. The purpose of this study was to develop a non-destructive technique by measuring fruit dimensions and fruit volume by water displacement to measure fruit growth and using this information to develop a method for predicting fruit weight at different stages of its development. Materials and MethodsThis experiment was conducted using the mature vines of ‘Hayward’ kiwifruit. The kiwifruit vines were grown in an orchard located in Astara, Guilan province, Iran (latitude 38.22°N and longitude 48.51°E), trained to a T-bar system with plants spaced of 4×5 m. Fruits were destructively harvested at one-two weeks after fruit set during the season to obtain measurements of individual fruit volume by water displacement, fruit fresh weight, circumference of fruit and three linear measurements of fruit size, from which a correlation relation was derived to enable estimation of fruit volume, fruit fresh weight from the fruit measurements (r> 0.995). This enabled the growth of tagged fruit on the vine to be followed by nondestructive measurements of the fruit dimensions and the growth curves of each mean were estimated at each measurement step.Results and DiscussionThe increase in the fresh weight or volume of 'Hayward' fruit over the season was a double sigmoid in shape. The fruit density was less than one in about three months after the fruit set and then increased to more than one unit. Correlation analysis between the data of different stages of measurement with fruit harvesting data showed that with the progress of fruit growth, the correlation between fruit size and its final size increased, and about 55 days after fruit set reached to more than 0.95. The standard deviation of fruit size at this stage was 11.55 cm3. The correlation coefficient above 0.95 between fruit weight and its length with fruit weight and length at harvest time was calculated 72 and 89 days after fruit set, respectively. Fruit size in kiwifruit is affected by various factors and the final size and weight of the fruit is likely to be determined by the rapid fruit growth period. This period that results from cell division and cell size enlargement took about 50-60 days after fruit set for Hayward cultivar when the fruit reaches approximately half of its volume in this period. Applying any stress at the cell division stage will affect the final fruit size. Given the high correlation between the dimensions of the fruit with the final fruit size at the end of the rapid growth period, it is possible to predict the final fruit size at the end of this period with great accuracy. Therefore, using the obtained mathematical equations, the final size of the fruit can be estimated by the measurement of the length and circumference of fruit in one and a half months to two after the fruit set. ConclusionBased on the results of this study, with a simple and practical method and with a high and significant correlation coefficient, by measuring the length and circumference of the fruit about one and a half months to two after fruit formation, the final fruit size at harvest can be predicted in order to take the necessary measures to export, sell and/or store the fruit.

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Keywords = Weight

Evaluation of the Effects of Calcium Nitrate and Potassium Phosphite on the Storage Life and Some Quality Traits of Thomson Navel Orange

Abstract

Predicting the Final Fruit Size of Kiwifruit cv. 'Hayward' Using Mathematical Equations

Abstract