۲۸۱پ
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بررسی تنوع ژنتیکی گونه‌های اژیلوپس (Aegilops) شمال غرب ایران از طریق روش های نواربندی کروموزومی و الکتروفورز ایزوزیم ها
/رسول اصغری زکریا
: کشاورزی
۱۵۲ص
جدول، نمودار، عکس
چاپی
واژه نامه بصورت زیرنویس
کتابنامه ص.: ۱۳۹-۱۵۲
دکتری
مهندسی کشاورزی-اصلاح نباتات
۱۳۸۲/۰۶/۲۵
تبریز
گونه‌های اژیلوپس از مهمترین خویشاوندان وحشی گندم و یکی از غنی‌ترین منابع ژنی در اصلاح گندم به شمار می‌آیند .منطقه شمال غرب ایران از جمله مناطقی در جهان است که از لحاظ رویش این گونه‌ها خیلی غنی بوده و از مراکز تنوع آنها می‌باشد .به منظور ارزیابی تنوع ژنتیکی در چند گونه از جنس اژیلوپس، پژوهشی بر اساس مطالعه ویژگی‌های کاریولوژیکی و الگوی نواربندی C کروموزوم‌ها و نیز الکتروفورز ایزوزیم‌ها با ۲ سیستم آنزیمی GOT و EST در ۳۵ جمعیت طبیعی از ۵ گونه مختلف اژیلوپس شامل ۱۲ جمعیت از گونه Ae. tauschii، ۱۰ جمعیت از هریک از گونه‌های Ae. cylindrica وAe. triuncialis، یک جمعیت از گونه Ae. crassa
Aegilops species, the most important wild relatives of wheat, are the rich genetic resources in wheat breeding. The northwest of Iran is rich in growth of these species. In order to analyse genetic variation in some species of this genus, an experiment was conducted based on karyological characteristics and C-banding patterns of mitotic chromosomes and isozyme electrophoresis of GOT and EST isozymes using 35 natural populations from 5 species including 12 populations of Ae. tauschii, 10 populations from each of the Ae. cylindrica and Ae. triuncialis, 2 from Ae. umbellulata and one from Ae. crassa species, collected from different geographical regions of northwestern Iran. Aceto-iron-hematoxilin staining and C-banding technique were used to study karyological characteristics and C-banding patterns in eight different genomes of these species. The karyogram of each genome was constructed and chromosome characteristics including long arm, short arm and chromosome lengths, arm ratio, and relative length indices from at least ten plants were then measured and number of bands and banding patterns as also evaluated in at least five plants in each population. Karyotype analysis revealed that D genome of Ae. tauschii, Ae. cylindrica and Ae. crassa species consisted of 7 pairs metacentric chromosomes, which one pair of them was SAT chromosome (5D chromosome). Minor variations were observed for karyological characteristics such as arm ratios and relative lengths of chromosomes between different populations of Ae. tauschii and Ae. cylindrica species. However, a considerable polymorphism (heteromorphism) as to possessing or lacking some C-bands among different populations of these species was observed. The two varieties of Ae. tauschii (Eusquarrosa and Strangulata) showed minor differences for karyological characteristics and C-banding patterns. Three species of Ae. tauschii, Ae. cylindrica and Ae. crassa showed a great amount of variation for karyological characteristics and C-banding patterns of their common D genomes, as they grouped in separate clusters. C genome of Ae. cylindrica and Ae. triuncialis consisted of one metacentric, two sub-metacentric and four acrocentric chromosomes. In this genome there were two chromosomes with NOR regions (1C and 3C). Significant differences for arm ratio indices of 3C, 5C, 6C and 7C chromosomes and also for relative length of 1C and 7C chromosomes among of different populations of Ae. cylindrica were observed. The differences for arm ratio indices of 2C, 3C, 4C, 6C and 7C chromosomes as well as for relative length of 1C, 4C, 5C and 6C chromosomes among population of Ae. triuncialis species were also significant. A great number of polymorphic bands were also observed among different populations of each species and between these species. As for D genome, each chromosome of C genome had also monomorph bands, which were effective in recognizing of the chromosomes. Ae. cylindrica were different from Ae. triuncialis for karyological characteristics and C-banding patterns of C genome, as they clustered in two separate groups. The chromosome formula of U genome in Ae. umbellulata and Ae. triuncialis were as 2m: 2sm: 3st and 3m: 2sm: 2st, respectively, with two SAT chromosomes (1U and 5U).There were minor differences between two populations of Ae. umbellulata, however, a great amount of polymorphism were observed among different populations of Ae. triuncialis for karyological characteristics and C-banding patterns of U genome chromosomes. The average allele per locus at 5 loci studied in GOT and EST enzymes was 1.7, ranged 1.00 to 2.60 allele per locus in Ae. crassa and Ae. columnaris, respectively. the mean value of observed heterozygosity in all species was 0.12. Its highest value (H0=0.38) was observed in Ae. speltoides which is an open-pollinated species. It ranged 0 to 0.23 in other species. This shows that except for Ae. crassa, which seems to be completely self-pollinated, other self-pollinated species such as Ae. tauschii and Ae. cylindrica exhibited some degree of open-pollination. Gene diversity in polyploid species was greater than its amount in diploid species (0.15 in diploid and 0.25 in polyploid species). The average gene diversity in all populations was 0.23. The coefficient of differentiation (GST) values among different populations of Ae. cylindrica, Ae. tauschii and Ae. triuncialis showed that in these species about 84.5, 77.9 and 65.7 percent of total gene diversity is related to inter-populations component (DST) and rest to that of within-populations component (HS). Likewise, the average inter-population component of total gene diversity in all populations studied was about 59.9 and that of within-population component was about 40.1 . Genetic distance between diploid species was greater than of distance between diploid and polyploid species. The genetic distance between species exhibited their genomic relationships, in some manner.
اصغری زکریا، رسول
کاظمی، حمداله، استاد راهنما
آقایف، یوسف، استاد راهنمای همکار
ولیزاده، مصطفی، استاد مشاور
مقدم، محمد، استاد مشاور همکار
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