عنوان مقاله [English]
Introduction: Cucumis melo L. is a plant from the Cucurbitaceae family. Many researchers consider the early habitat of this plant to be African, which has gradually become domesticated in Iran and Egypt. Melon fruit has undergone many physical and chemical changes during the growing season from the flowering to the maturity. Since these changes have a direct impact on the fruitfulness of fruit juices, the knowledge of process of these changes can be helpful in farm management include fertilizers, irrigation, and so on. The use of X-ray radiation in study of fruits quality and other agricultural products has always been of interest to researchers. The purpose of this study is to provide a method that is able to inspect melon fruits in non-destructive and accurate.
Materials and Methods: In this research, two local populations of melon, ‘Ghasri’ and ‘Khatooni’, were used. In summer of 2017, the specimens were collected from two adjacent farms from Abrvan village with a geographical position of 59° 58′ 40″ and 36° 4′ 34″ and an approximate height of 930 m above sea level. With the advent of flowers, a number of them were plated and harvested in 15, 30 and 45 days after flowering. In the ‘Khatooni’ population, as the fruit reaches its full maturity earlier than the ‘Ghasri’, the harvesting time was considered 40 days after flowering. In this research, the Optima-CT540, CT-Scan made by GE Healthcare was used. This device can display up to 16 cuts per round. All selected melons are in the direction of longitudinal diameter, which is the largest diameter of the fruit and entered into the device on the head. The images were loaded in the Microview medical software (v. 21), and the volume of seed cavity and the total volume of melon fruit were calculated. In this research, the quantitative change factor was a percentage of cavity volume percentage (Cavity) along with factors such as moisture content percentage, soluble solids, volumetric weight, and pH, with simultaneously changing two qualitative variables of "Melon variety " (with two levels of ‘Ghasri’ and ‘Khatooni’). The nominal variable "harvesting stage" (with three levels) was performed using multivariate analysis of variance (MANOVA) and combined with Duncan's multiple range test using SPSS (v. 24) software. Normality of data was also evaluated by the SPSS software. Data was analyzed at 1% of probability level.
Results and Discussion: The results of this study showed that as the fruit grows, the volume of seed cavity increases, but the rate of this increase is lower than the increase in total fruit volume. This causes the percentage of seed cavity to decline during the growing season. Meanwhile, there is a decrease in the amount of ‘Ghasri’, which has a larger lateral mass compared to the ‘Khatooni’. By decreasing the volume of seed cavity during the growth period, the percentage of moisture content and specific gravity of fruit is reduced. The moisture content decreased from 94.04 to 90.61% in ‘Ghasri’ and from 93.52 to 89.12% in ‘Khatooni’, which showed a significant difference (p ≤ 0.01) at each stage. The percentage of soluble solids increased from a minimum of 4.97% in the type of ‘Khatooni’ to a maximum of 12.74% in the ‘Ghasri’ type during the growing season, and the pH value in this experiment was from a minimum of 4.53 in the type of ‘Khatooni’ to the maximum value of 5.98 has changed in ‘Ghasri’.
Conclusion: The results of this study showed correlation between the dependent variables of moisture content, the percentage of soluble solids, volumetric weight and pH with independent variable of seed cavity volume in ‘Ghasri’ population. In addition, the apparent impact of two harvesting stages and the variety on other factors was evident. In the meantime, the use of X-Ray Computed Tomography Techniques as a non-destructive method to observe the internal variation of the fruit has helped to study the intrinsic properties of melon fruit.