Introgression lines of an Indica-type rice variety IR64 with unique agronomic traits


IR64 was released by the International Rice Research Institute (IRRI) in 1985, and has been widely accepted as a high quality rice variety in many countries. In the late 1980s, a breeding program to develop a new plant type (NPT) of rice was launched at IRRI with the goal of increasing yield potential under tropical environments. In this study, the NPT varieties were chosen for experiments designed to improve the yield potential of IR64.
  A total of 334 introgression lines (INLs) derived from crosses between IR64 and 10 donor varieties (mostly NPT varieties) have been developed as breeding materials for rice yield enhancement under the IRRI–Japan Collaborative Research Project Phases III and IV. The agronomic traits of the 334 INLs were evaluated in IRRI during Phase V of the project from 2005 to 2007 and the genotypes of the 334 INLs were clarified using more than 400 SSR markers. Based on the data of phenotype and genotype for these INLs, a total of 54 regions were detected to be associated with the eight traits:  7 regions for days to heading, 8 for culm length, 8 for leaf width, 4 for leaf length, 6 for panicle length, 3 for panicle number per plant, 7 for 100-grain weight, and 11 for total spikelet number per panicle. The developed 334 INLs with the IR64 genetic background will be useful materials for genetic analysis of agronomic traits as well as breeding for genetic enhancement of yield potential of rice varieties.

Figure, table

  1. Table 1. Donor parents, no. of developed lines and no. of polymorphic DNA markers between the parents of IR64 introgression lines

    Table 1.

    Fig. 1.

Japan International Research Center for Agricultural Sciences Biological Resources Division


Administration A

Term of research


Responsible researcher

KOBAYASHI Nobuya ( Biological Resources Division )

FUJITA Daisuke ( International Rice Research Institute )

Imbe Tokio ( Kyushu Okinawa Agricultural Research Center, NARO )

Kato Hiroshi ( Institute of Crop Science, NARO )

FUKUTA Yoshimichi ( Biological Resources Division )

Publication, etc.

Fujita et al. (2009) Field Crops Res. 114:244-254.

Fujita et al. (2010) JARQ 44:277-290.

JIRCAS Working Report No.66 (2010)

Japanese PDF

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