The aim of this work was to study patterns of growth and of fibre aggregation in four cultivars of pomegranate (Punica granatum), ‘Torsh-e-Zabol’ (TZ), ‘Malas-e-Yazdi’ (MY), ‘Zagh-e-Yazdi’ (ZY), and ‘Bihast-e-Dane Sefid-e-Ravar’ (BDSR), classified as hard-, semi-hard-, semi-hard-, and soft-seeded genotypes, respectively.To investigate patterns of lignification and seed characteristics, fruit were sampled at nine developmental stages: 0, 7, 14, 21, 28, 42, 56, and 105 d after fruit set (DAFS) and at harvest (156 DAFS). The results showed that the fruit growth curve for the cultivar BDSR was sigmoidal, while the other three cultivars showed some variation in their patterns of growth. Rapid increases in seed diameter and length were observed up to 28 DAFS in all cultivars, and these continued at a slower rate up to 56 DAFS. Measuring seeds with a high content of fibre showed that fibre formation and aggregation began in the seed coat during the early weeks of fruit development and continued for 56 DAFS. Among the four cultivars tested, TZ had the highest values for aril weight, seed fresh weight (FW) and dry weight (DW), and woody index (i.e., the FW of the woody portion/seed FW), while BDSR had the lowest values of these parameters. The results of this study indicate that hard-seeded pomegranate cultivars with larger seed contained a higher percentage of fibre in their seed coat, whereas soft-seeded cultivars, such as BDSR, showed less fibre aggregation in their seed coat.
