با همکاری انجمن علمی منظر ایران
نوع مقاله : مقالات پژوهشی
نویسندگان
1 استاد دانشکده کشاورزی دانشگاه زنجان
2 گروه علوم باغبانی، دانشکده کشاورزی، دانشگاه زنجان، ایران
3 موسسه تحقیقات علوم باغبانی، سازمان تحقیقات ، آموزش و ترویج کشاورزی، کرج ، ایران
4 موسسه تحقیقات علوم باغبانی، سازمان تحقیقات، آموزش و ترویج کشاورزی، اهواز، ایران
کلیدواژه‌ها
عنوان مقاله English
نویسندگان English
Introduction: The walnut is one of the most important fruits which has been defined as a "superfood" in recent years, garnering significant attention for its high nutritional value, flavor, and aroma. Walnut production and productivity have increased significantly over the past two decades in leading walnut-producing countries such as China, Türkiye, and Iran. In Iran, although the area under cultivation has expanded more rapidly than in competing countries, yield per unit area has declined; this trend is attributed to the use of seedling-derived trees for orchard establishment and increasing climatic stresses specifically damage caused by late spring frosts. Today, top-working (crown grafting) is employed as the optimal and fastest method to modify tree canopies and convert seedling-based orchards into high-yielding orchards featuring improved cultivars that are tolerant to late spring frosts and other biotic and abiotic stresses. In recent years, the practice of replacing walnut tree canopies with improved cultivars has expanded rapidly, with numerous projects currently underway through government support or orchardists' own initiatives.
Material and methods: To monitor and evaluate the growth of top-worked walnut trees in Hamedan Province, the county of Tuyserkan designated as the "Global Walnut City" and the site of the most extensive walnut top-working activity was selected as the pilot area. In this project, several orchards grafted with the 'Chandler' cultivar were selected across various elevations. Over a four-year period (2021–2024), the phenological, vegetative, and fruiting characteristics of the top-worked trees were evaluated across different locations within the county, ranging from 1500 to 2100 meters above sea level. Measurements included the timing of leaf emergence, the number of catkins, the number of female flowers, fruit count and fruit set percentage per tree, tree canopy radius and cross-sectional area, as well as the timing of physiological maturity and harvest.
Results and discussion: The results of this study during 2021–2024 showed that with increasing altitude (1500–2100 m aboves sea level) harvest (up to October 19) were delayed. Based on the results, both of site and cultivar showed significant effects on the characteristics of leafing time, harvest time, yield and quality. Based on the results, the altitude of the orchard location showed significant effects on the characteristics of leafing time, harvesting time, yield and quality. The number of fruits per tree and the percentage of fruit formation, which varied between 21 and 45 percent, increased with increasing tree age and reaching maturity of the grafted trees. The latest physiological ripening time occurred at an altitude of 2100 meters and the earliest physiological ripening time was at an altitude of 1500. The largest cross-sectional area of the tree crowns was obtained at an altitude of 1500 meters above sea level and the lowest amount of these traits was also obtained at an altitude of 2100 meters above sea level. In Hamadan province and other parts of the country, the greatest concern arises from the incorrect location of the late-leaved walnut orchards and incorrect orchard management (mixed cultivation with forage and summer crops) or without considering the proportion of pollinating varieties planted. Unfortunately, thousands of seedlings without pollinators are distributed every year. Although the production of grafted seedlings of the Late leafing cultivars was started in the region 20 years ago (2005), the production of grafted seedlings has peaked in the past 10 years, and unfortunately, unauthorized people without knowledge of the fruiting behavior of these cultivars are also trying to propagate and distribute these seedlings, so that the production of grafted walnut seedlings has reached saturation point from zero in 2001 to 2024. Walnut cultivation in Tuyserkan is possible up to an altitude of 2100 meters above sea level, but at higher altitudes, achieving optimal productivity requires appropriate management methods that are compatible with climatic conditions.
Conclusion: Based on the overall results, both of site and cultivar showed significant effects on the characteristics of leafing time, harvest time, yield and quality. the latest physiological ripening time occurred at an altitude of 2100 meters and the earliest physiological ripening time was at an altitude of 1500. In West Hamadan province and other parts of the country, the greatest concern arises from the incorrect location of the late-leaved walnut orchards and incorrect orchard management (mixed cultivation with forage and summer crops) or without considering the proportion of pollinating varieties planted. Unfortunately, thousands of seedlings without pollinators are distributed every year. Walnut cultivation in Hamadan Province is feasible up to an altitude of 2100 meters above sea level, but at higher elevations achieving optimal productivity requires more precise and improved management practices.
کلیدواژه‌ها English
