The Relationship Between Soil Physicochemical Properties and Fruit Quality of Certain Quince Varieties and Genotypes During Postharvest Storage

Introduction
A noteworthy aspect of quince trees is their susceptibility to chlorosis caused by iron deficiency in calcareous soils. Most of the quince genotypes identified in Iran are found in central regions (Tehran, Alborz, Isfahan, etc.) (Abdollahi, 2019), where soil lime content varies significantly. In the Tehran province, particularly in Damavand, soil lime content ranges from 10% to 44% (Fallahi, 1977). Unfortunately, there are no precise estimates of iron chlorosis damage in fruit trees in Iran. However, given the widespread distribution of calcareous soils in the country, lime-induced soil issues can potentially affect many fruit orchards. Some sources report up to 70% yield loss in pome fruit trees under calcareous soil conditions in Iran (Pirmoradian, 2019). Moreover, extensive genetic diversity in quince trees has been reported in Iran. Several studies on soil science and agricultural land classification in Iran over the past 40 years, conducted by the Soil and Water Research Institute, have shown that high to very high levels of soil calcium carbonate and alkaline pH are major limiting factors for the productivity of many fruit orchards (Jamshidi et al., 2014). In central regions, soil calcium carbonate levels range between 10% and 44% for soils with medium to heavy textures (Nurbbakhsh, 1999; Fallahi, 1977; Banaei, 2017). The genetic diversity of quince trees and varying levels of soil lime can significantly influence the physicochemical changes in quince fruit during storage (Mirabdulbaghi et al., 2023). Although valuable information is available in scientific literature regarding the appropriate harvest time, storability, and fruit quality of quince varieties/genotypes (Gunes et al., 2012; Radović et al., 2020), there is a lack of documented research in Persian on the relationship between soil physicochemical properties and fruit quality. Therefore, this study aims to investigate the physicochemical properties of soils with varying lime levels in loamy, loamy-clay, and silt-loamy-clay textures, with alkaline pH, and their impact on the quality indices of quince fruit during storage.
 
Materials and Methods
The research was conducted at the Kamelabad research orchard in Karaj, belonging to the Horticultural Research Institute/Central Research Institute for Temperate Fruits Research Center during the years 2020 and 2021. In 2020, the experiment was conducted on the fruits of the KVD1 genotype (variety 'Vidoja'), KVD3 genotype (variety 'Esfahan Quince'), PH2 genotype (variety 'Behta'), as well as promising genotypes (NB4, NB2, KVD2). In 2021, the genotypes KVD3 (variety 'Esfahan Quince') and PH2 (variety 'Behta'), along with the promising genotypes NB4 and NB2, were subjected to statistical calculations. At the start of the project, the trees were in their ninth year of planting. As per regional practice, the fruits were harvested on November 3rd (in 2020) and November 1st (in 2021), packed in five-fruit packages, and stored at a temperature of 1 to 2°C with 80-90% relative humidity in a cold storage facility for quality testing at storage durations of 0, 60, and 120 days. The study area is classified as having a Mediterranean climate with hot, dry summers and cold winters. Soil physicochemical properties were measured to assess soil lime content (%), total nitrogen (%), available phosphorus and potassium (mg/kg), pH, organic matter (%), and soil texture (%) before the experiment (Table 1). Physicochemical characteristics, i.e., the pH, total acidity (TA, %), total soluble solids (TSS, Brix), fruit flavor index (TSSA/TA) and moisture content (MC, %), , as well as the contents of some fruit mineral elements were measured at harvest and in two-month intervals during cold storage. The experiment was performed in a split-plot arrangement on the basis of the Randomized Complete Block Design (RCBD) with 3 replications, 10 trees per replicate, and 6 seedling quince cultivarsThe main plots were the different levels of soil lime equivalent (10%, 12%, 14%, 16%, and 18%) and the subplot consisted of the seedlings of 6 cultivars/promising genotypes.The SPSS statistical software was utilized to assess the surveyed data.
 
Results and Discussion
When examining the obtained results and comparing them with domestic and foreign scientific sources, it can be acknowledged that in areas with soils of varying degrees of lime, as well as semi-heavy to heavy texture and alkaline pH, the length of the storage period in cold storage can significantly improve the quality and shelf life of fruits. Accurately adjusting the storage period in these areas can have significant positive effects on maintaining the quality characteristics of fruits. Scientific sources recommend a storage period of up to five months for quince cultivars (Tatari et al., 2019). However, the results of this research showed that the physicochemical characteristics and nutrient concentrations in the fruit of quince cultivars (Vidoja, Beh Isfahan, Behta) and promising genotypes (NB4, NB2, KVD2) varied during the storage period, influenced by the amount of lime and soil texture.
 
Conclusion
Our research findings indicated that fruit quality during cold storage is influenced by varying levels of soil calcium carbonate equivalent, cultivar, and storage duration. Although in terms of taste index, the promising genotype NB4 and the cultivar Behta can be considered as genotypes and cultivars tolerant to soils with up to 18% calcium carbonate equivalent. Additionally, this study revealed that at high soil lime levels (18% calcium carbonate equivalent), one cannot expect a suitable ratio of nutritional elements such as Ca/Mg+K, N/Ca, and Bˣ10-3/Ca, which play a crucial role in the manifestation of physiological nutritional disorders. They exhibited (brown spots on the fruit, water-soaked areas, reduced sweetness, discoloration, and tastelessness) during the storage period.