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Alireza Talaie*, Ahmad Ershadi and Ali Vezvaei

In order to study pollination and fruit set and determine the best pollinizers for two Iranian apple cultivars, Golab Kohanz and Shafiabadi, experiments were conducted during two years. Different pollen sources including pollen of cultivars Golab Isfahan, Golab Kohanz, Mashhad Nouri, Shafiabadi and also open pollination were used. Pollen sources had significant effects on fruit set, fruit weight, diameter, shape, dry weight, total soluble solids (TSS), sugar and seed contents in cv. Golab Kohanz. Trees pollinated by pollen of Shafiabadi had highest fruit set, fruit weight, diameter, shape, dry weight, TSS., sugar, and seed content. Pollen sources significantly affected fruit set, fruit weight, diameter, shape, and seed content in cv. Shafiabadi. The highest fruit set, fruit weight, diameter, and seed content was resulted from flowers pollinated by Golab Kohanz. Golab Kohanz and Shafiabadi had 3.3% and 0.5% fruit set from self pollination, respectively, and seemed to be completely incompatible. Fruit resulted from self pollination were generally small and of low quality. Regardless to fruits obtained from pollination, different pollen sources had small effects on fruit quality. The results indicated that cvs. Shafiabadi and Mashad Nouri are the best pollinizers for Golab Kohanz and Golab Kohanz was superior pollinizers for Shafiabadi.

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Ali Akbar Ghasemi Soloklui, Ahmad Ershadi and Esmaeil Fallahi

Freezing injury is one of the most important limiting factors in commercial pomegranate production. The objectives of this study were to compare cold hardiness of seven Iranian pomegranate cultivars at three stages: November, January, and March, and to investigate the relationship between freezing tolerance and soluble carbohydrate and proline changes of shoots during acclimation and deacclimation. LT50 values, estimated by both electrolyte leakage measurement (EL LT50) and tetrazolium stain test (TST LT50), allowed us to discriminate between the cultivars in terms of freezing tolerance. Acclimation and deacclimation did not occur simultaneously in different cultivars, having a key role in cold tolerance of cultivars, especially in fall and late winter. Post Sefid Bafgh cultivar showed high cold tolerance early in fall, but it was susceptible to cold during winter. ‘Naderi’, ‘Yusef Khani’, ‘Malas Saveh’, and ‘Robab Neyriz’ had the highest midwinter cold hardiness; ‘Mahabadi’ showed an intermediate hardiness, whereas ‘Post Sefid Bafgh’ and ‘Shishe Kap’ were found to be cold-susceptible in this period. Freezing tolerance estimated by TST corresponded to those measured by the EL method in all cultivars, but in November and January, higher variation in freezing tolerance was observed among the cultivars through TST compared with EL measurement. However, LT50 values, estimated by EL measurement, were lower than those estimated through TST in November and March. Soluble carbohydrate concentrations of stem samples increased during cold acclimation from November to January; then it decreased in March. Proline had a narrow range of variation among the cultivars in November, but an increase in the amount of proline was observed during the period of hardening. In general, stronger correlations were observed between LT50 values and the amounts of soluble carbohydrates compared with proline, particularly from fall to midwinter.

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Rohollah Karimi, Ahmad Ershadi, Kourosh Vahdati and Keith Woeste

The genetic structure and diversity of natural populations of Juglans regia L. in Iran were characterized using 11 microsatellite loci. A total of 105 individuals from seven populations were sampled. A high level of genetic diversity was observed within populations with the number of alleles per locus (A) ranging from three to 11 (average = 5.73), the proportion of polymorphic loci was 100%, and the expected heterozygosity ranged from 0.598 to 0.848 (average = 0.707). The proportion of genetic differentiation present among populations accounted for 12% of the total variation. Such considerable interpopulation differentiation detected in J. regia L. could have resulted from several factors, including restricted gene flow between populations. Significant departures from Hardy-Weinberg equilibrium were observed for WGA276, WGA32, and WGA321 loci. The deviations were primarily the result of the surplus of heterozygotes. The unweighted pair group method with arithmetic mean cluster analyses based on Nei's unbiased genetic distances separated the seven populations into two main groups.