Improving the resistance of Jinshan S-2 to rice blast through marker-assisted backross breeding.

In this study,blast-resistant gene Pi-2 was introduced into rice sterile line Jinshan s-2,via successive backcrosses using line 5173 as the donor.The marker SRM24 was employed to trace the target gene in every generation until BC3F2.Nine desirable plants were selected in BC3F2 according to their blast resistance markers and other morphological traits.The 4 selected lines were analyzed in BC3F1 by sequence-related amplified polymorphism(SRAP) markers for comparing genetic background with recurrent parent,Jinshan s-2.The result showed they appeared high similarity with recurrent parent.And they maintained also male sterility of the acceptor.It was found that the isogenic lines had resistance of rice blast by artificial inoculation in BC3F1∶2,suggesting that the resistant gene had been really introduced into Jinshan s-2 and so using SRM24 for the selection was reliable.Therefore,near isogenic lines of Jinshan s-2 with improved blast resistance were acquired.