Effects of different scion-rootstock combinations on vigor, tree size, yield and fruit quality of three Iranian cultivars of pomegranate. Abstract-Introduction. Probably because pomegranate trees are established in orchards as own-rooted plants, there are no studies regarding scion-rootstock combination effects on growth, tree size, yield and fruit quality of this fruit tree. Thus, the main aims of our experiment were to study the effects of some pomegranate rootstocks on growth and yield characteristics of Iranian commercial cultivars used as scions. Materials and methods. Our research was carried out between the 1999 and 2007 growing seasons at a collection of 760 pomegranate cultivars in the Yazd Province of Iran. Rootstocks were provided via clonal propagation using stem cuttings similar in height, diameter and age (2 years old) from '

Chilling and heat requirements can affect agroclimatic distribution, growing season, and the marketing period of pomegranate (Punica granatum L.) cultivars in commercial production. This study was carried out to determine the chilling and heat requirements of 20 Iranian pomegranate cultivars/accessions, and to also examine the correlation of these features with tree and fruit characteristics, as well as geographic and climatic parameters of the original environment the plant materials came from. One-year-old stem cuttings from mature trees were used for measurements of chilling and heat requirements. The results showed a range of variation in chilling requirement among cultivars from 233 to 633 hours and heat requirement from 4096 to 7928 growing degree hour (GDH). Based on chill hours accumulated, cultivars including Bihaste Ravar, Bihaste Sangan Khash, and Anar Siah were categorized as very low chill (233–266 hours), whereas cultivars Poost Nazok Torosh Abarkuh, Malas Yazdi, Jangali Poost Ghermez Roodbar, Rabab Poost Ghermez Neyriz, and Makhmal Malas Shahreza were grouped as low chill (600–633 hours). Variation in seed hardness from 15 to 78 N was also recorded. Chilling requirement showed a moderate correlation with stomatal density, seed hardness, and wind speed (r = 0.42, 0.44, and −0.39, respectively), whereas stomatal density showed correlations of r = −0.34 and −0.57 with altitude and wind speed, respectively. We suggest taking chilling and heat requirements into account when selecting individual’s cultivars and/or accessions suitable for cultivation in different agroclimatic regions.