1 Ullah et al. Int. J. Biosci. 2020 RESEARCH PAPER OPEN ACCESS Molecular analysis of bacterial blight resistance gene XA7 in advance population of rice using STS markers Irfan Ullah * , Hamid Ali, Muhammad Islam, Wazi Ullah, Muhammad Haris, Muhammad Qasim Khan, Shafiq-ur-Rehman, Kamran Khan, Kabir Khan, Bushra Ghani Department of Genetics, Hazara University Mansehra, Pakistan Key words: BB; Molecular screening; Rice; Xanthomonas oryzae pv. Oryzae. http://dx.doi.org/10.12692/ijb/17.5.1-10 Article published on November 12, 2020 Abstract Rice plays a vital role in achieving world food security. However, it is affected by several biological factors. Among these factors, Bacterial blight (BB) negatively effect rice efficiency and reduce rice production through out the world. In this study a molecular survey was conducted to identify BB resistance gene Xa7 in an advance population of rice using STS markers. An amplicon of 207bp in size was observed in IRBB7 confirming the presence of Xa7 gene. An amplicon of the same size was also observed in 11 other genotypes. The selected genotypes were then evaluated against BB local isolates in the field. Significant differences were recorded for mean lesion length developed by these isolates. However, all the selected genotypes along with the parental variety IRBB7 showed resistant reactions. Therefore, the presence of Xa7 gene in rice will confer durable resistance against different isolates of bacterial blight. * Corresponding Author: Irfan Ullah  irfan.qasami@gmail.com International Journal of Biosciences | IJB | ISSN: 2220-6655 (Print), 2222-5234 (Online) http://www.innspub.net Vol. 17, No. 5, p. 1-10, 2020