Molecular Detection and Resistance Determination of Rice Blast-resistance Genes

To avoid a possible loss of blast-resistance in rice when a single resistance gene was dependent upon for the disease prevention, new rice varieties with durable rice blast-resistance were cultivated. Forty-eight field materials of advanced-generation were obtained through a multiple-generation selection from the crosses using 4 maintainer lines, 6 restorer lines and 3 conventional rice varieties as receptor parents with 75-1-127 (harboring blast gene Pi9) and U19 (harboring blast resistance gene Pi25) as donor parents. Evaluated by their resistance to the leaf blast disease, 5 lines were classified as highly resistant, 25 moderately resistant, and the remainders moderately or highly susceptible varieties. A marker-assisted selection showed that, among them, 19 advanced-generation lines carried blast-resistance gene Pi9, and 5 had blast-resistance gene Pi25.