Karamatlou Issa, Navabpour Saeid, Nezhad Khalil Zaynali, Mariotti Roberto, Mousavi Soraya, Hosseini-Mazinani Mehdi
Department of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
Department of Plant Breeding and Biotechnology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Front Plant Sci. 2023 May 9;14:1140270. doi: 10.3389/fpls.2023.1140270. eCollection 2023.
Olive ( L.) is one of the most cultivated tree species in Iran. This plant is characterized by its tolerance to drought, salt, and heat stresses while being vulnerable to frost. During the last decade, periods of frost have occurred several times in Golestan Province, in the northeast of Iran, which caused severe damage to olive groves. This study aimed to evaluate and individuate autochthonous Iranian olive varieties with regard to frost tolerance and good agronomic performance. For this purpose, 218 frost-tolerant olive trees were selected from 150,000 adult olive trees (15-25 years old), following the last harsh autumn of 2016. The selected trees were reassessed at different intervals, i.e., 1, 4, and 7 months after the cold stress in field conditions. Using 19 morpho-agronomic traits, 45 individual trees with relatively stable frost-tolerance were reevaluated and selected for this research. Ten highly discriminating microsatellite markers were used for the genetic profiling of the 45 selected olive trees, and, ultimately, five genotypes with the highest tolerance among 45 selected ones were placed in a cold room at freezing temperatures for image analyses of cold damage. The results of morpho-agronomic analyses evidenced no bark splitting or symptoms of leaf drop in the 45 cold-tolerant olives (CTOs). The oil content of the cold-tolerant trees comprised almost 40% of the fruit dry weight, highlighting the potential of these varieties for oil production. Moreover, through molecular characterization, 36 unique molecular profiles were individuated among the 45 analyzed CTOs that were genetically more similar to the Mediterranean olive cultivars than the Iranian ones. The present study demonstrated the high potential of local olive varieties, which would be promising and more suitable than commercial olive varieties, with regard to the establishment of olive groves under cold climate conditions. This could be a valuable genetic resource for future breeding activities to face climate changes.
油橄榄(Olea europaea L.)是伊朗种植最为广泛的树种之一。这种植物的特点是耐旱、耐盐、耐热,但易受霜冻影响。在过去十年中,伊朗东北部的戈勒斯坦省多次出现霜冻期,给橄榄园造成了严重破坏。本研究旨在评估和鉴定具有抗冻性且农艺性能良好的伊朗本土油橄榄品种。为此,在经历了2016年最后一个严酷的秋季后,从15万株成年油橄榄树(15 - 25岁)中挑选出了218株抗冻油橄榄树。在田间条件下,对选定的树木在冷胁迫后的不同时间间隔(即1个月、4个月和7个月)进行了重新评估。利用19个形态农艺性状,对45株抗冻性相对稳定的单株进行了重新评估并选作本研究对象。使用10个高度有鉴别力的微卫星标记对45株选定的油橄榄树进行基因分型,最终,在45株选定的油橄榄树中,将耐受性最高的5个基因型置于冷冻温度的冷藏室中进行冷害图像分析。形态农艺分析结果表明,45株抗冻油橄榄(CTO)均未出现树皮开裂或落叶症状。抗冻树的油含量几乎占果实干重的40%,突出了这些品种在油脂生产方面的潜力。此外,通过分子特征分析,在45株分析的CTO中鉴定出36个独特的分子图谱,这些图谱在遗传上与地中海油橄榄品种比与伊朗品种更为相似。本研究证明了当地油橄榄品种的巨大潜力,在寒冷气候条件下建立橄榄园方面,它们比商业油橄榄品种更有前景且更合适。这可能是未来应对气候变化的育种活动的宝贵遗传资源。