ارزيابي تنوع ژنتيكي ژنوتيپ‌هاي مختلف زيتون در برخي از شهرستان‌هاي استان خوزستان با استفاده از نشانگر مورفولوژيكي

Evaluation of Genetic Diversity of Different Olive Genotypes in Some Cities of Khuzestan Province Using Morphological Marker

ژوهشها نشان دادهاند كه برخي از صفات مورفولوژيكي ميوه، هسته و برگ گياه زيتون نظير كمتر تحت تأثير محيط قرار مي‌گيرند و هر گونه تغييري در اين صفات نتيجه تغيير در خزانه‌ژني گياه است لذا پژوهشي به ‌منظوربررسيتنوعژنتيكي 50 ژنوتيپ زيتون در شهرستان‌هاي باغملك، انديكا، ايذه و لالي استان خوزستان با استفاده از خصوصيات مورفولوژيكي ميوه، هسته و برگ در قالب طرح آماري لانه آشيانه‌اي در سال 1395-1394 به اجرا درآمد. نتايج نشان داد كه دامنهوسيعيازتغييرات مورفولوژيكيدر بينژنوتيپ‌ها وجود داشت. نتايج تجزيه به عامل‌ها نيز نشان داد كه 12 مؤلفه در مجموع 78/7 درصد از واريانس كل صفات را توجيه نمودند. اولين مؤلفه 13/42 درصد از واريانس كل را توجيه نمود و در اين عامل، طول ميوه (0/63)، عرض ميوه 0/61)، وزن‌تر ميوه (0/61)، شكل هسته (0/7-)، عرض هسته (0/66)، طول هسته (0/44-)، تعداد شيار (0/40) و طول برگ (5/0) ضريب بالايي داشتند. همچنين صفاتي نظير طول و عرض ميوه، هسته و برگ، شكل هسته و برگ، خمش برگ، تعداد شيار هسته، قاعده ميوه در موقعيت A، وزن هسته، سطح هسته در موقعيت B، تقارن هسته در موقعيت A، اندازه عدسك روي ميوه، توزيع شيار روي هسته، تقارن هسته در موقعيت B از جمله مهم‌ترين صفات در تفكيك ژنوتيپ‌ها و گروه‌بندي شهرستان‌هاي مورد مطالعه از يكديگر بودند. بر اساس نتايج حاصل از تجزيه خوشه‌اي، ژنوتيپ‌ها به شش گروه مجزا تقسيم شدند. ژنوتيپهاي متعلق به شهرستان باغملك داراي بيشترين يكنواختي اما ژنوتيپهاي متعلق به شهرستان لالي، ايذه، انديكا داراي بيشترين غيريكنواختي بودند.

Background and Objectives Olive (Olea europaea) is compatible with Mediterranean and Mediterranean-like climates. Due to its high adaptability to different environmental conditions, this plant has adapted well to the varied climates in the world. It has extensively been cultivated in some regions of Iran to the extent that some cultivars do not have any identification. Therefore, a genotype/variety may be classified under several names and several varieties under a single name. Also, lack of garden information, re-naming of imported cultivars, and non-standard morphological traits for naming has led to fundamental problems in the pomology industry. Accordingly, it is necessary and inevitable to eliminate these ambiguities and accurately identify different olives’ genotypes in Iran. Hense, the first step in identifying the genotype is morphological identification. To this aim, the present research was conducted to investigate the genetic diversity and the relationship between the olive trees cultivated in some of the cities of Khuzestan through exploring morphological traits. Materials and Methods This study was conducted in Indica, Baghmalek, Izeh, and Lali in 2015-2016. Fifty genotypes were collected from the orchards of the Andika, Baghmalek, Izeh and, Lali. The morphological traits of fruit, stone, and leaf were measured according to the IOOC guidelines and the Seed and Plant Certification and Registration Institute for Research (2007) guidelines. The variance analysis of the traits was performed using SAS 9.1 software as a nested design. Cluster analysis was used for the determination of the degree of relationship between genotypes. The main components and biplot analysis were used to reduce the number of variables. Results The results showed that there was a wide range of morphological variations among genotypes. Factor and principal components analysis showed that 12 components could justify 87.7% of the variation among genotypes. The first component explained 13.42% of the total variance. In this factor, fruit length (0.63), fruit width (0.61), fruit weight (0.61), stone shape (-0.7), stone width (0.66), stone length (-0.44), and leaf length (0.5) had a high coefficient. Moreover, traits such as length and width of fruit, stone and leaf, stone and leaf shape, curvature of leaf, stone number grooves, fruit base in position A, stone weight, stone surface in position B, stone symmetry in position A, fruit size of lenticels, stone distribution of grooves, stone symmetry in position B, were the most important traits in genotyping and grouping of the cities studied. Based on the results of cluster analysis, the genotypes were divided into six distinct groups. Discussion In general, it was found that most of the genotypes in Baghmalek city are located in a separate cluster. In contrast, several genotypes in Lali, Izeh, and Indica are situated in a single cluster, which can be due to atmospheric differences in precipitation rates in these cities. Izeh, Lali, and Indica have lower temperatures and more atmospheric precipitation than Bagmalek. This important difference can cause the genotypes of these cities to be different compared to Baghmalek city.