Construction and Genetic Background Recovery of Blast-resistant Near-isogenic Lines from Japonica Variety, Yunyin

Construction of near-isogenic lines(NILs) is an effective mean for analyzing blast-resistance genes as well as genetic research in general. This study applied the broad-spectrum blast-resistant japonica variety, Yunyin, as the donor parent and the blast-susceptible variety, LTH, as the recurrent parent. Combining the molecular markers assisted selection and artificial inoculation, 7 blast-resistant NILs were bred with LTH for the genetic background analysis after 4 generations of backcrossing and 8 generations of self-crossing.184 pairs of SSR markers evenly distributed on 12 chromosomes of the rice were selected to evaluate the genetic background of the NILs. The results showed that 72 pairs of SSR primers to be polymorphic with a frequency of 39.1%. The polymorphisms between 7 NILs and LTH were analyzed by markers among the parents. The background recovery rates of W15 and W17 were 97.61%, that of W18, 97.22%, and those of other 4 lines, greater than 98%. It appeared that the construction of NILs carrying Yunyin blast-resistance gene with LTH as background were successful, and that all phenotypic indices of the NILs recovered well in this study.