Chilling and Heat Requirements of 20 Iranian Pomegranate Cultivars and Their Correlations with Geographical and Climatic Parameters, as well as Tree and Fruit Characteristics

Abstract

<jats:p>Chilling and heat requirements can affect agroclimatic distribution, growing season, and the marketing period of pomegranate (<jats:italic>Punica granatum</jats:italic> 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 (<jats:italic>r</jats:italic> = 0.42, 0.44, and −0.39, respectively), whereas stomatal density showed correlations of <jats:italic>r</jats:italic> = −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.</jats:p>

Assessment of Climate Change Impacts on Chilling and Forcing for the Main Fresh Fruit Regions in Portugal

“…It is clear that under future climates and lower overall chilling, some of these varieties will tend to migrate to other regions, depending on the regional climate conditions. The importance of variety selection for crop adaptation has been highlighted by several studies ( Soloklui et al, 2017 ; Rodriguez et al, 2019 ).…”

Pomegranate freezing tolerance evaluation and its relationship with biochemical parameters

“…Moreover, despite the ambiguous role of physiological parameters in relation to FT, the correlation of their changes seems to be an effective indicator in interpreting the results. Despite the spreading of commercial pomegranate cultivars to new areas, their low chill requirements (~200-600 h) [23], and high vulnerability to untimely warming and deacclimation in mid-winter [19], information about their physiological responses to freezing stress is limited. Accordingly, the present study aimed to (i) identify the relative FT of four Iranian pomegranate cultivars based on different freezing laboratory tests, (ii) compare different tests, and consequently detect the best fitting method, and (iii) analyze the correlation between some physiological indices and FTs.…”