The purpose of waste reduction and cleaner production is achieved by properly managing crop production including efficient fertilization and subsequent crop marketing. In recent years, the issue of colorless arils has turned to a critical damage in the pomegranate orchards of Iran resulting in the probable loss of pomegranate export market. Accordingly, finding suitable methods, which may alleviate such a disorder, is of significance. The foliar application of Fe and Zn mineral fertilization as well as chelated Fe (total of 12 treatments) on pomegranate quality along with genotype effect (two genotypes) was hypothesized. The experiment was a factorial on the basis of a completely randomized block design with three replications, conducted in Bajestan city of Khorasan-Razavi province, Iran. Fruit Fe and Zn content, anthocyanin, sugar, titratable acidity (TitA), pH and colorless arils (PCA) disorder were determined. The results showed the significant interactions of fertilization treatments on Fe and Zn contents compared with the single effects. Fertilization treatments also increased anthocyanin concentrations. Fe fertilization affected fruit taste by significantly affecting fruit sugar, TitA and pH. Some fertilization treatments significantly alleviated the disorder of colorless arils (16.17e14.17%), compared with the other treatments. G1 (higher Fe concentration) was the more tolerant genotype to PCA than G2. The results confirms the necessity of Fe and Zn (both mineral and organic) for alleviating PCA disorder and enhancing pomegranate quality using Fe and Zn mineral and chlelated fertilization, along with the proper genotype. The results are promising and can be used for the further research in this respect.

Introduction

Pomegranate (Punica granatum) is one of the most consumed fruits in different parts of the world including Iran (Jamali, and Bonyanpour, 2017); among the European countries Spain is the main producer of pomegranate (Viuda-Martos et al., 2010). The importance of pomegranate fruit is because of its many desirable traits, taste, medicinal properties, and organic production (Melgarejo-Sanchez et al., 2015
; Zinatloo-Ajabshir et al., 2018). The pomegranate fruit has a major role in human nutrition and health, because it is a source of minerals such as iron (Fe), zinc (Zn), and manganese (Mn), and it also contains vitamin C, A and antioxidants such as anthocyanin. The fruit is also of industrial significance as it is used for the production of different products including the favorable pomegranate juice. It must be noted that the efficient use of pomegranate requires the proper utilization of resources such as the macro and micronutrients required for the plant growth and fruit production (Ozlekci et al., 2013; Ben-Ali et al., 2017; Houshyar et al., 2017). Siebielec et al. (2018) indicated that the use of sewage sludge can enhance the fertility of soil by increasing the population and activities of soil microbes resulting in the higher rate of microbial enzyme production. The essential nutrients such as Fe and Zn can significantly enhance pomegranate fruit quality, which is both of economical and marketing significance, and can considerably decrease the rate of waste in the environment resulting in a cleaner production. Iron and zinc deficiency, especially under calcareous conditions, causes disorders in plant metabolic processes (Sabet and Mortazaeinezhad, 2018).