نوع مقاله : کامل علمی - پژوهشی
نویسندگان
1 دانشیار مؤسسه تحقیقات اصلاح و تهیه بذر چغندرقند- سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران
2 دانشجوی دکتری بیماری شناسی گیاهی، دانشگاه آزاد اسلامی، واحد ورامین- پیشوا.
3 استادیار مؤسسه تحقیقات اصلاح و تهیه بذر چغندرقند سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران.
4 استادیار گروه گیاه پزشکی، دانشکده کشاورزی، دانشگاه آزاد اسلامی واحد ورامین- پیشوا، ورامین، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Rhizoctonia root and crown rot is the most important fungal disease in sugar beet fields in the Iran and the most effective way to manage this disease is to develop resistant varieties. For genotypic screening of improved sugar beet lines, molecular markers linked to resistance genes to rhizoctonia pathogen are needed. In this research, the flanking sequences of a SNP molecular marker identified at the university of Padua, Italy were obtained and at the Sugar Beet Seed Institute, a pair of specific primers were designed and converted into a repulsion STS marker called SR2-r with normal PCR capability. This repulsion marker is able to identify homozygous resistant genotypes in the gene locus related to the marker. To check the reproducibility and confirm the repulsion marker SR2-r, first, several populations and breeding lines of the available germplasm of the Sugar Beet Seed Institute (SBSI) were cultivated in microplots or in the greenhouse at different times. Then, the developed roots were inoculated with corn seeds infested to rhizoctonia pathogen. Leaf samples were prepared from the inoculated plants and kept at -70°C until use. After a few weeks of inoculation, single roots were taken from microplots or pots, and the rhizoctonia disease score in each root was recorded and disease index of each genotype calculated and the genotyps classified. In next step, susceptible and resistant plants were selected and DNA was extracted from their frozen leaves. PCR molecular analysis was performed with primers related to the repulsion marker in the DNA of susceptible and resistant plants and the presence and absence of the marker in single plants was determined. In the next step, the relationship between the repulsion molecular marker results and the rhizoctonia disease score was studied in the form of a pairwise comparison in all the tested plants. The results showed 87% agreement between molecular markers and phenotypic resistance in greenhouse or microplot conditions. This repulsion marker was able to identify 48% of rhizoctonia resistant plants. However, due to the unexpected presence of very weak bands in some resistant homozygous genotypes, it is suggested to carry out real-time PCR if possible.
کلیدواژه‌ها [English]
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