Development of Differential Varieties for Blast Resistance in IRRI-Japan Collaborative Research Project

Abstract

In the International Rice Research Institute (IRRI)-Japan Collaborative Research Project, 4 kinds of differential varieties, monogenic lines and near isogenic lines (NILs) with 3 kinds of genetic backgrounds have been developed for the following 24 blast (Magnaporthe grisea) resistance genes Pia, Pib, Pii, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pita, Pita-2, Pit, Piz, Piz-5 (Pi2), Piz-t, Pi1, Pi3, Pi5 (t), Pi7, Pi9 (t), Pi11 (t), Pi12 (t), Pi19 (t) and Pi20. Monogenic lines that have only a single resistance gene in each background, were developed from one to 3 time's backcrosses between donor varieties and a Japonica-type variety Lijianxintuanheigu (LTH) as a recurrent parent, and were distributed as first universal differential varieties and gene sources from IRRI. Two kinds of NILs with LTH and US2 genetic backgrounds have also only one resistance gene each. The NILs of an indica-type variety CO39 are including an additional gene Pia in the genetic background. These NILs are confirming fixations of target resistance gene and morphological characters in the advanced generations BC6F7 or more, and will be released in the near future.